THE SECRETARY 

OF THE INTERIOR’S 

STANDARDS FOR 

THE TREATMENT 

OF HISTORIC 

PROPERTIES 

WITH 

GUIDELINES FOR 

PRESERVING, 

REHABILITATING, 

RESTORING & 

RECONSTRUCTING 

HISTORIC 

BUILDINGS 

U.S. Department of the Interior 

National Park Service 

Technical Preservation Services 
Under the National Historic Preservation Act (NHPA), the Secretary 

of the Interior is responsible for establishing professional standards 

and for providing guidance on the preservation of the nation’s 

historic properties. The Secretary of the Interior’s Standards for the 

Treatment of Historic Properties apply to all grants-in-aid projects 

assisted through the Historic Preservation Fund (authorized by 

the NHPA) and are intended to be applied to a wide variety of 

resource types, including buildings, sites, structures, objects, and 

districts. The Standards address four treatments: preservation, 

rehabilitation, restoration, and reconstruction. The treatment 

Standards, developed in 1992, were codified as 36 CFR Part 68 in 

the July 12, 1995, Federal Register (Vol. 60, No. 133). They replaced 

the 1978 and 1983 versions of 36 CFR Part 68, entitled The Secretary 

of the Interior’s Standards for Historic Preservation Projects. The 

revised Guidelines herein replace the Guidelines for Preserving, 

Rehabilitating, Restoring, and Reconstructing Historic Buildings, 

published in 1995 to accompany the treatment Standards. 

The Secretary of the Interior’s Standards for the Treatment of Historic 

Properties are regulatory only for projects receiving Historic 

Preservation Fund grant assistance and other federally-assisted 

projects. Otherwise, these Guidelines are intended to provide 

general guidance for work on any historic building. 

Another regulation, 36 CFR Part 67, focuses on “certified historic 

structures” as defined by the Internal Revenue Service Code of 1986. 

The Standards for Rehabilitation cited in 36 CFR Part 67 should 

always be used when property owners are seeking certification for 

federal tax benefits. 
THE SECRETARY OF THE INTERIOR’S STANDARDS 

FOR THE TREATMENT OF HISTORIC PROPERTIES 

WITH 

GUIDELINES FOR PRESERVING, REHABILITATING, 

RESTORING & RECONSTRUCTING HISTORIC BUILDINGS 

Revised by Anne E. Grimmer 

from The Secretary of the Interior’s Standards
 

for the Treatment of Historic Properties with
 

Guidelines for Preserving, Rehabilitating,
 

Restoring & Reconstructing Historic Buildings
 

Kay D. Weeks and Anne E. Grimmer (1995) 

U.S. Department of the Interior 

National Park Service 

Technical Preservation Services 

Washington, D.C. 

2017 
II

 

 

 

 

CONTENTS 

IV	 PHOTO CREDITS 

VI	 ACKNOWLEDGEMENTS 

VII	 PREFACE 

2	 INTRODUCTION 

Using the Standards and Guidelines for a Preservation, 

Rehabilitation, Restoration, or Reconstruction Project 

Choosing an Appropriate Treatment for the Historic 

Building 

4	 HISTORICAL OVERVIEW 

Building Materials 

Masonry • Wood • Metals 

Building Features and Systems 

Roofs • Windows • Entrances and Porches • Storefronts 

• Curtain Walls • Structural Systems • Mechanical

Systems 

Interior Spaces, Features, and Finishes 

Building Site 

Setting (District/Neighborhood) 

Code-Required Work: 

Accessibility • Life Safety 

Resilience to Natural Hazards 

Sustainability 

New Exterior Additions to Historic 

Buildings and Related New 

Construction 

27 STANDARDS FOR PRESERVATION 

& GUIDELINES FOR PRESERVING 

HISTORIC BUILDINGS 

29 INTRODUCTION 

31 

31 

37 

41 

BUILDING MATERIALS 

Masonry 

Wood 

Metals 

44 

44 

46 

49 

51 

53 

55 

58 

BUILDING FEATURES AND SYSTEMS 

Roofs 

Windows 

Entrances and Porches 

Storefronts 

Curtain Walls 

Structural Systems 

Mechanical Systems 
 

 

 

 

 

 

 

60 INTERIOR SPACES, FEATURES, 

AND FINISHES 

63 BUILDING SITE 

66 SETTING (DISTRICT/NEIGHBORHOOD) 

69 CODE-REQUIRED WORK 

69 Accessibility 

71 Life Safety 

72 RESILIENCE TO NATURAL HAZARDS 

74 SUSTAINABILITY 

75 STANDARDS FOR REHABILITATION 

& GUIDELINES FOR REHABILITATING 

HISTORIC BUILDINGS 

77 INTRODUCTION 

80 BUILDING MATERIALS 

80 Masonry 

88 Wood 

93 Metals 

98 BUILDING FEATURES AND SYSTEMS 

98 Roofs 

102 Windows 

110 Entrances and Porches 

113 Storefronts 

117 Curtain Walls 

121 Structural Systems 

125 Mechanical Systems 

128 INTERIOR SPACES, FEATURES, AND FINISHES 

137 BUILDING SITE 

143 SETTING (DISTRICT/NEIGHBORHOOD) 

147 CODE-REQUIRED WORK 

147 Accessibility 

150 Life Safety 

153	 RESILIENCE TO NATURAL HAZARDS 

155	 SUSTAINABILITY 

156	 NEW EXTERIOR ADDITIONS TO HISTORIC 

BUILDINGS AND RELATED NEW 

CONSTRUCTION 

163	 STANDARDS FOR RESTORATION 

& GUIDELINES FOR RESTORING 

HISTORIC BUILDINGS 

165	 INTRODUCTION 

III
IV

 

 

 

 

 

 

 

 

 

Contents Restoration (cont.) 

168 MATERIALS
 

168 Masonry
 

176 Wood
 

180 Metals
 

184 BUILDING FEATURES AND SYSTEMS
 

184 Roofs
 

187 Windows
 

190 Entrances and Porches
 

193 Storefronts
 

196 Curtain Walls
 

199 Structural Systems
 

202 Mechanical Systems
 

204 INTERIOR SPACES, FEATURES, AND FINISHES 

209 BUILDING SITE 

214	 SETTING (DISTRICT/NEIGHBORHOOD) 

218 CODE-REQUIRED WORK
 

218 Accessibility
 

220 Life Safety
 

222 RESILIENCE TO NATURAL HAZARDS 

224 SUSTAINABILITY 

225	 STANDARDS FOR RECONSTRUCTION & 

GUIDELINES FOR RECONSTRUCTING 

HISTORIC BUILDINGS 

227 INTRODUCTION 

230 OVERVIEW 

232 BUILDING EXTERIOR 

234 BUILDING INTERIOR 

236 BUILDING SITE 

238 BUILDING SETTING 

(DISTRICT/NEIGHBORHOOD) 

PHOTO CREDITS 

Front Cover: Spooner Hall, University of Kansas, Lawrence, KS, 

Henry van Brunt, 1894. 

HISTORICAL OVERVIEW 

Masonry. Detail, decorative sandstone door surround.
 

Wood. Detail, Pope-Leighey House, Alexandria, VA, Frank Lloyd Wright,
 

1940. Photo: Courtesy National Trust for Historic Preservation, Paul
 

Burk, photographer.
 

Metals. Detail, Dunbar Molasses Factory, New Orleans, LA, c. 1920.
 

Glass. Detail, St. John’s Abbey, Collegeville, MN, Marcel Breuer, 1958-61.
 
Paint and Other Coatings. Interior detail, Mabel Tainter Memorial 

Theater, Menomonie, WI, Harvey Ellis, 1889. Photo: Miller 

Dunwiddie Architecture. 

Composite Materials. Composite siding, Private Residence,
 

Washington, DC, William Lescaze, 1940.
 

Simulative Materials. Detail, wood used to simulate cut stone.
 

Roofs. Asphalt roof shingles on a 1920s-era house.
 

Windows. Paired wood windows with stained glass lunette on a
 

Romanesque revival-style rowhouse.
 

Entrances and Porches. Decorative stone entrance with etchedglass revolving door on early-20th century office building. 

Storefronts. Ellicott City, MD.
 

Curtain Walls. Simms Building, Albuquerque, NM, Flatow & Moore,
 

1954. Photo: Harvey M. Kaplan.
 

Structural Systems. Boiler Maker Shops, Navy Yard Annex, 

Washington, DC, 1919. 

Mechanical Systems. Historic Radiator.
 

Spaces, Features, and Finishes. Interior, Saenger Theater, New
 

Orleans, LA, Emile Weil, 1927. Photo: Courtesy Saenger Theater.
 

Site. Vineyard, Charles Krug Winery, St. Helena, CA. Photo: Rocco 

Ceselin. Inset: Redwood Cellar, 1872, Charles Krug Winery. Photo: 

Rien van Rijthoven. 

Setting. Late-19th-century residential historic district. 

Accessibility. Gradual slope added to sidewalk and paving for 

accessibility. Schmidt Brewery, St. Paul, MN, late 19th–early 20th 

century. 

Life Safety. Code-required, supplemental stair railing. 

Resilience to Natural Hazards. Farnsworth House, Plano, IL, Mies 

van der Rohe, 1951. Photo: Courtesy Farnsworth, A Site of the 

National Trust for Historic Preservation. 

Sustainability. Traditional sustainable features include deep 

porches and window shutters in southern architecture. 

New Additions and Related New Construction. Private Residence, 

Washington, DC, Cunningham/Quill Architects. Photo: © Maxwell 

MacKenzie. 

CHAPTER HEADS 

Preservation. Old Santa Fe Trail Building (National Park Service 

Intermountain Regional Office), Santa Fe, NM. This adobe building 

was designed by John Gaw Meem in the Spanish-Pueblo Revival 

style, and constructed for the National Park Service through the 

auspices of the Civilian Conservation Corps (CCC) and the Works 

Project Administration (WPA) in 1939. Photo: MRWM Landscape 

Architects. 

Rehabilitation. The Arcade, Providence, RI, 1828. Photo: Northeast 

Collaborative Architects, Ben Jacobson, photographer. 

Restoration. Montpelier, Montpelier Station, VA. National Trust for 

Historic Preservation, Administered by The Montpelier Foundation. 

Photo: Courtesy The Montpelier Foundation. 

Reconstruction. The Cathedral of Saint Michael the Archangel, 

Sitka, AK, built early 1840s, reconstructed 1961. Photo: Barek at 

Wikimedia Commons. 

Photographs not individually credited are from National Park 

Service files. 

V
VI

ACKNOWLEDGEMENTS 

This edition of The Secretary of the Interior’s Standards for the 

Treatment of Historic Properties with Guidelines for Preserving, 

Rehabilitating, Restoring and Reconstructing Historic Buildings has 

been produced in part to ensure that the National Park Service 

continues to fulfill its responsibility to promote the preservation 

of the historic buildings that are part of the nation’s cultural 

heritage. This has been a collaborative effort undertaken by the 

office of Technical Preservation Services (TPS) in the National 

Park Service, with the assistance of other National Park Service 

programs, State Historic Preservation Offices (SHPO), the 

Advisory Council on Historic Preservation, Federal Agency 

Historic Preservation Officers, the National Trust for Historic 

Preservation, and others. The comments and suggestions 

provided by these agencies and organizations, together with 

important contributions from the TPS professional staff, 

have been invaluable in the development of this revised and 

updated guidance on preserving, rehabilitating, restoring, and 

reconstructing historic buildings that accompany The Secretary of 

the Interior’s Standards for the Treatment of Historic Properties. 
 

PREFACE

The year 2016 was significant as the Centennial of the National 

Park Service, which was established as a new bureau within the 

Department of the Interior by the Organic Act on August 25, 1916. 

As directed in this legislation, the National Park Service has served 

for one hundred years as steward of the “Federal areas known as 

national parks, monuments and reservations...to conserve the scenery and the natural and historic objects and the wild life therein and 

to...leave them unimpaired for the enjoyment of future generations.” 

The year 2016 also marked the 50th anniversary of the passage of 

the National Historic Preservation Act on October 15, 1966. The 

Act increased the scope and responsibilities of the National Park 

Service with regard to the preservation of cultural resources. The 

National Historic Preservation Act charges the National Park Service 

(through authority delegated by the Secretary of the Interior) to 

establish and administer a national historic preservation program 

and to develop and promulgate standards and guidelines for the 

treatment of historic properties. 

The Secretary of the Interior’s Standards for Historic Preservation 

Projects were first issued in 1978. In 1979 they were published with 

Guidelines for Applying the Standards and reprinted in 1985. The 

Standards were revised in 1992, when they were retitled The Secretary of the Interior’s Standards for the Treatment of Historic Properties. 

The Standards were codified in the Federal Register in 1995, the 

same year that they were published with guidelines as The Secretary 

of the Interior’s Standards for the Treatment of Historic Properties with 

Guidelines for Preserving, Rehabilitating, Restoring and Reconstructing 

Historic Buildings. These Standards and Guidelines provide a critical 

part of the framework of the national preservation program. They 

are widely used at the federal, state, and local levels to guide work 

on historic buildings, and they also have been adopted by Certified 

Local Governments and historic preservation commissions across 

the nation. 

In 2010 the National Park Service issued A Call to Action: Preparing 

for a Second Century of Stewardship and Engagement, a plan to chart a 

path for its next 100 years. This plan identified a number of actions 

with the goal to “preserve America’s special places in the next 

century,” which included updating National Park Service policies 

and guidance. The project to update The Secretary of the Interior’s 

Standards for the Treatment of Historic Properties with Guidelines for 

Preserving, Rehabilitating, Restoring and Reconstructing Historic Buildings was undertaken as part of this broader effort. 

Since these Guidelines were first published in 1995, a greater number 

of buildings and building types, telling a broader range of stories that 

are part of the nation’s heritage, have been recognized as “historic” 

VII
 

and eligible for listing in the National Register of Historic Places. 

These guidelines have been updated and expanded to address the 

treatment of these buildings constructed with newer materials and 

systems from the mid- and late-20th century. 

The updated Guidelines have the same organization as the prior 

version, beginning with an introduction and a historical overview, 

followed by chapters that focus on each of the four treatments: 

preservation, rehabilitation, restoration, and reconstruction. The 

historical overview has been expanded; not only has the information on historic materials, systems, features, and special issues that 

comprised the previous edition been more fully developed, but new 

entries have been added on glass, paint and other coatings, composite materials, imitative materials, and curtain walls. 

In each of the four chapters, the “Recommended” and “Not Recommended” treatments have been updated and revised throughout to ensure that they continue to promote the best practices in 

preservation. The section on exterior additions to historic buildings in the Rehabilitation Guidelines has been broadened also to 

address related new construction on a building site. A section on 

code-required work is now included in all of the chapters. “Energy 

Efficiency” has been eliminated, since it is more fully covered by the 

guidance provided on sustainability in The Secretary of the Interior’s 

Standards for Rehabilitation and Illustrated Guidelines on Sustainability 

for Rehabilitating Historic Buildings (published in 2011), which has 

general applicability to all the treatments and is incorporated here 

by reference. Sections on “Resilience to Natural Hazards” have been 

added, but these topics will be more fully addressed in separate 

documents and web features. Finally, the updated Guidelines feature 

all new, and many more, illustrations in color. 

Herewith Technical Preservation Services issues the National Park 

Service Centennial edition of The Secretary of the Interior’s Standards 

for the Treatment of Historic Properties with Guidelines for Preserving, 

Rehabilitating, Restoring and Reconstructing Historic Buildings, updated 

and revised in recognition of the 50th anniversary of the National 

Historic Preservation Act, to ensure that the preservation guidance 

for historic buildings provided by the National Park Service continues to be meaningful and relevant in the 21st century. 

Technical Preservation Services 

National Park Service 

VIII
 

 

Technical Preservation Services 

National Park Service 

The office of Technical Preservation Services (TPS) in the Cultural 

Resources directorate of the National Park Service is responsible for 

developing and promulgating preservation standards and guidance 

specifically as it relates to historic buildings. TPS has produced an 

extensive amount of technical, educational, and policy guidance 

on the maintenance and preservation of historic buildings. TPS 

developed the original and current versions of The Secretary of 

the Interior’s Standards for the Treatment of Historic Properties with 

Guidelines for Preserving, Rehabilitating, Restoring and Reconstructing 

Historic Buildings. The many technical publications and web 

features on preserving historic buildings prepared by TPS are well 

known, especially the Preservation Briefs and the Preservation Tech 

Notes series. It is not feasible to include a complete list here of all 

the materials available from TPS because of the sheer volume of 

information. Materials developed by TPS are available in printed 

form and/or online from the TPS website at https://www.nps.gov/ 

tps (or search for Technical Preservation Services at https://www. 

nps.gov). TPS also administers the Federal Historic Preservation Tax 

Incentives Program, which encourages private sector investment in 

the rehabilitation and reuse of historic buildings. 

IX
2

INTRODUCTION

Using the Standards and Guidelines for 

Preservation, Rehabilitation, Restoration, 

and Reconstruction Projects 

The Secretary of the Interior’s Standards for the Treatment of Historic Properties address four treatments: preservation, rehabilitation, 

restoration, and reconstruction. As stated in the regulations (36 CFR 

Part 68) promulgating the Standards, “one set of standards ...will 

apply to a property undergoing treatment, depending upon the property’s significance, existing physical condition, the extent of documentation available, and interpretive goals, when applicable. The 

Standards will be applied taking into consideration the economic and 

technical feasibility of each project.” These Standards apply not only 

to historic buildings but also to a wide variety of historic resource 

types eligible to be listed in the National Register of Historic Places. 

This includes buildings, sites, structures, objects, and districts. 

Guidelines, however, are developed to help apply the Standards to a 

specific type of historic resource. Thus, in addition to these Guidelines for Preserving, Rehabilitating, Restoring and Reconstructing 

Historic Buildings, there are also guidelines for cultural landscapes, 

historic lighthouses, historic vessels, historic furnished interiors, and 

historic covered bridges. 

The purpose of The Secretary of the Interior’s Standards for the Treatment of Historic Properties and Guidelines for Preserving, Rehabilitating, 

Restoring and Reconstructing Historic Buildings is to provide guidance 

to historic building owners and building managers, preservation 

consultants, architects, contractors, and project reviewers prior to 

beginning work. It is always recommended that preservation professionals be consulted early in any project. 

The Guidelines are intended as an aid to assist in applying the Standards to all types of historic buildings. They are not meant to give 

case-specific advice or address exceptions or unusual conditions. 

They address both exterior and interior work on historic buildings. Those approaches to work treatments and techniques that are 

consistent with The Secretary of the Interior’s Standards for the 

Treatment of Historic Properties are listed in the “Recommended” 

column on the left; those which are inconsistent with the Standards 

are listed in the “Not Recommended” column on the right. 

There are four sections, each focusing on one of the four treatment 

Standards: Preservation, Rehabilitation, Restoration, and Reconstruction. Each section includes one set of Standards with accompanying Guidelines that are to be used throughout the course of a 

project. 

Preservation is defined as the act or process of applying measures necessary to sustain the existing form, integrity, and materials of an historic 

property. Work, including preliminary measures to protect and stabilize 

the property, generally focuses upon the ongoing maintenance and repair 

of historic materials and features rather than extensive replacement and 

new construction. The limited and sensitive upgrading of mechanical, electrical, and plumbing systems and other code-required work to make properties functional is appropriate within a preservation project. However, 

new exterior additions are not within the scope of this treatment. The 

Standards for Preservation require retention of the greatest amount 

of historic fabric along with the building’s historic form. 

Rehabilitation is defined as the act or process of making possible a compatible use for a property through repair, alterations, and additions while 

preserving those portions or features which convey its historical, cultural, 

or architectural values. The Rehabilitation Standards acknowledge the 

need to alter or add to a historic building to meet continuing or new 

uses while retaining the building’s historic character. 
Restoration is defined as the act or process of accurately depicting the 

form, features, and character of a property as it appeared at a particular 

period of time by means of the removal of features from other periods in its 

history and reconstruction of missing features from the restoration period. 

The limited and sensitive upgrading of mechanical, electrical, and plumbing systems and other code-required work to make properties functional 

is appropriate within a restoration project. The Restoration Standards 

allow for the depiction of a building at a particular time in its history 

by preserving materials, features, finishes, and spaces from its period 

of significance and removing those from other periods. 

Reconstruction is defined as the act or process of depicting, by means 

of new construction, the form, features, and detailing of a non-surviving 

site, landscape, building, structure, or object for the purpose of replicating 

its appearance at a specific period of time and in its historic location. The 

Reconstruction Standards establish a limited framework for recreating a vanished or non-surviving building with new materials, primarily for interpretive purposes. 

The Guidelines are introduced with a brief overview of the primary materials used in historic buildings; the exterior and interior 

architectural features and systems; the building’s site and setting; 

code-compliance requirements regarding accessibility and life-safety 

resilience to natural hazards; sustainability; and new additions and 

related new construction. This overview establishes the format of 

the Guidelines that follow. 

Choosing an Appropriate Treatment for the 

Historic Building 

The Guidelines are intended to promote responsible preservation 

practices that help protect the nation’s irreplaceable cultural 

resources. For example, they cannot, in and of themselves, be used 

to make essential decisions about which features of the historic 

building should be saved and which can be changed. But, once 

a treatment is selected, the Standards and Guidelines provide a 

consistent philosophical approach to the work. 

Choosing the most appropriate treatment for a building requires 

careful decision making about a building’s historical significance, as 

well as taking into account a number of other considerations: 

Level of Significance. National Historic Landmarks, designated 

for their “exceptional significance in American history,” and other 

properties important for their interpretive value may be candidates 

for Preservation or Restoration. Rehabilitation, however, is the most 

commonly used treatment for the majority of historic buildings 

Reconstruction has the most limited application because so few 

resources that are no longer extant can be documented to the degree 

necessary to accurately recreate the property in a manner that conveys its appearance at a particular point in history. 

Physical condition. Preservation may be appropriate if distinctive 

materials, features, and spaces are essentially intact and convey 

the building’s historical significance. If the building requires more 

extensive repair and replacement, or if alterations or a new addition 

are necessary for a new use, then Rehabilitation is probably the most 

appropriate treatment. 

Proposed use. Many historic buildings can be adapted for a new use 

or updated for a continuing use without seriously impacting their 

historic character. However, it may be very difficult or impossible 

to convert some special-use properties for new uses without major 

alterations, resulting in loss of historic character and even integrity. 

Code and other regulations. Regardless of the treatment, regulatory requirements must be addressed. But without a sensitive design 

approach such work may damage a building’s historic materials and 

negatively impact its character. Therefore, because the ultimate use 

of the building determines what requirements will have to be met, 

some potential uses of a historic building may not be appropriate if 

the necessary modifications would not preserve the building’s historic 

character. This includes adaptations to address natural hazards as well 

as sustainability. 

3
4

HISTORICAL OVERVIEW
 

Masonry 

Stone is one of the more lasting masonry building materials and has 

been used throughout the history of American building construction. Stones most commonly used in historic buildings in the U.S. 

are quarried stone, including sandstone, limestone, marble, granite, 

slate, basalt, and coral stone, and gathered stone, such as fieldstone, 

river rock, and boulders. Types of stone differ 

considerably in hardness, durability, and 

other qualities. Building stones were usually 

laid with mortar, but sometimes they were 

laid without mortar using a dry-stack method 

of construction. Brick varies in size and 

permanence. Before 1870, brick clays were 

pressed into molds and were often unevenly 

fired. The quality of historic brick depended 

on the type of clay available and the brickmaking technique; by the 1870s, with the 

perfection of an extrusion process, bricks 

became more uniform and durable. Architectural terra cotta is also a kiln-fired clay product popular from the late 19th century until 

the 1930s. Its use became more widespread 

with the development of steel-frame, highrise office buildings in the early 20th century. 

Glazed ceramic architectural siding was also 

used as cladding in high-rise buildings somewhat later. Adobe, which consists of sun-dried 

earthen bricks, was one of the earliest building materials used in the U.S., primarily in the 

Southwest where it is still popular. 

Mortar is used to bond together masonry 

units. Historic mortar was generally quite 

soft, consisting primarily of lime and sand with other additives. 

Portland cement, which creates a more rigid mortar, was first manufactured in the U.S. in the early 1870s, but it was not in common use 

throughout the country until the early 20th century. Thus, mortar 

used in buildings from around 1873 until the 1930s ranged from a traditional lime-cement mix to a variety of sand and Portland cement 

combinations. After this time, most mortar mixes were based on 

Portland cement. Like historic mortar, early stucco was also heavily lime based, increasing in hardness with the addition of Portland 

cement in the late 19th century. 

Concrete has a long history. It is composed of sand, crushed stone, or 

gravel bound together with lime and, sometimes, natural hydraulic 

cements. As a construction material concrete is used in a variety of 

forms, including blocks or units, poured or cast-in-place, and precast 

panels. Cast stone and other manufactured products began to be 

used around the 1860s as substitutes for natural stone. There are 

also cementitious materials specific to certain regions, such as tabby, 

which includes crushed shells and is found primarily in coastal areas 

in the southeastern part of the country. In the 20th century, reinforced concrete was developed and has since become one of the most 

commonly used materials in modern building construction. 

While masonry is one of the most durable historic building materials, it is also very susceptible to damage by exposure, improper 

maintenance or repairs, abrasive cleaning, or the application of nonpermeable coatings. 
Wood 

Wood is one of the most essential materials used in American buildings of every period and style. Its many and varied attributes make 

it suitable for multiple uses, including structural members, siding, 

roofing, interior finishes, and decorative features. Many of the first 

structures in the earliest settlements were built with logs, which 

were readily available, did not require much finishing, and could be 

quickly erected with basic tools. 

Water-powered sawmills cut logs into timbers and boards, but 

detailed ornamental features were generally crafted on site using 

hand tools until after the Civil War. Mechanized production 

increased the efficiency of cutting logs into timbers, boards, and 

more intricate components, and the structural and decorative potential of wood’s use in building construction expanded. With more 

efficient production came lower costs, but also the standardization 

of ready-made moldings and assemblies for windows, doors, and 

decorative features. Initially, wood was primarily sourced locally, but 

improved transportation systems made a greater variety of wood 

species more accessible all over the country. With broader availability, a particular wood could be selected for its suitability in a specific 

application; however, local species were used most often. 

The extensive use of wood in buildings can be attributed to its many 

properties that include strength in both tension and compression; 

ease with which it can be cut and shaped; capability to be connected 

using a variety of fasteners and adhesives; ability to be painted or 

varnished; and resistance to wear and weather. All of these characteristics, and some more than others, vary according to the species 

of wood. Although many types and species of wood used historically 

are no longer available, wood selection and construction practices 

have always capitalized on its attributes and compensated for it is 

weaknesses. Their resistance to decay made white oak and cedar 

common choices for roofing shingles, while oak and maple were 

frequently chosen for flooring because of their hardness. Pine and 

yellow poplar have often been used for siding and trim because of 

their straight grain and ease of milling, but they must be painted to 

protect them from decay. 

Plywood is an engineered product formed by laminating thin sheets 

of wood together; it was introduced to the U.S. building industry 

in the early 20th century. Because plywood has greater structural 

potential than wood, and as a sheet can be installed more efficiently, 

it soon replaced boards as sheathing before being replaced itself 

by less-expensive particle board for many applications. By applying 

surface veneers and adhesives, plywood can also be used as siding 

or for fine interior finishes on paneling or cabinetry. Glued laminated timber (glulam), first manufactured in the 1930s, is another 

engineered wood material. It is an important material in mid-20thcentury buildings and often used for massive arches and trusses in 

sports arenas and similar large, open, column-free spaces. 

Many historic buildings have wood structural systems and features, 

such as stairs or columns. The majority of both practical and decorative features, particularly on the interior, are made of wood, such as 

flooring and paneling. 

5
6

Metals 

Metal features—including steps, porches, railings, balconies, and 

entire facades; cornices, siding, cladding, roofs, roof cresting, and 

storefronts; and doors, window sash, entablatures, and hardware— 

are often highly decorative as well as practical and are important in 

defining the overall character of historic American buildings. 

Metals commonly used in historic buildings include lead, tinplate, 

terneplate, zinc, copper, bronze, brass, iron, steel, aluminum, stainless 

steel, and a variety of other alloys. Historic metal building components were often designed by highly-skilled artisans. By the late 19th 

century, many of these components were prefabricated and available 

from catalogues in standardized sizes and designs. 

Wrought iron is the form in which iron was first used in America. In 

the beginning, most wrought-iron architectural elements were small, 

such as nails, tie rods, straps, and hardware. Wrought-iron features 
gradually increased in size to include balconies, railings, porches, 

steps, and fencing. It was not used for structural components until 

around the mid 19th century, when manufacturing equipment 

became more sophisticated. Cast iron was initially imported from 

England. Although there were some iron-casting works established 

before the Revolution, by the early 19th century production had 

expanded to make a variety of cast-iron features. Structural castiron columns were first used in the 1820s, and cast-iron building 

fronts and decorative structural and ornamental features followed 

soon after. Cast and wrought iron are often used on the interior of 

historic buildings as both structural and decorative features, such as 

columns, staircases, railings, and light fixtures. 

Steel, which is an alloy of iron and usually carbon, increased in 

popularity as manufacturing processes and production improved in 

the mid-19th century. Structural steel played an important role in 

the development of high-rise buildings and the skyscraper. 

Lead was first used in historic buildings for roofing. Tinplate or 

terneplate, which was made by applying a lead and tin coating to 

sheet metal or steel, became a common roofing material after it was 

first produced in the 1820s. (Pure tin was rarely used as a building 

material because it is so soft.) The application of a zinc coating on 

sheet metal created galvanized iron, which was used for roofing and 

decorative roofing features, such as steeples and roof cresting, as 

well as other ornamental architectural features, such as door and 

window hood molds, lintels, and oriel and bay windows. Prefabricated Quonset huts constructed of corrugated galvanized steel began 

to be manufactured during World War II for the military on the 

battlefield for housing, storage, and other uses. 

Entire pressed-metal and galvanized-iron storefronts and individual 

decorative features were manufactured to simulate wood, stone, or 

cast iron from the latter part of the 19th century into the early years 

of the 20th century. Copper roofs were installed on many public 

buildings from the 1790s through the first quarter of the 19th century. Copper continues to be used, often for porch roofs as well as 

gutters, downspouts, and flashing. Bronze and brass are both alloys 

of copper. Bronze, which weathers well, appears as entrance doors 

and historic storefronts. Brass, usually polished, is used for decorative interior features, such as grilles and elevator doors. Nickel, 

when employed as a building component, is in the form of an alloy, 

usually nickel silver, Monel, or some stainless steel. In comparison to 

other construction metals, stainless steel is quite new, essentially 

only coming into use in the 1920s when it became a favorite material 

for Art Deco-style buildings. 

Aluminum—lightweight and corrosion-resistant—was not utilized 

much in buildings because it was so expensive until the 1920s, when 

expanded production reduced its cost. Aluminum siding, which was 

advertised as maintenance free, became a popular siding material 

for single-family residences after it was introduced in the late 1930s. 

Some of the uses of aluminum include roofing and roofing features, 

such as gutters, downspouts, and flashing, as well as windows and 

storefront surrounds. 

Porcelain enamel, or vitreous enamel, is composed of a thin coating 

of glass fused to cast-iron or steel sheets, panels, tiles, or shingles. 

Although developed in the late 19th century, it was not commonly 

used in buildings until the late 1920s and 1930s for Art Deco and Art 

Moderne storefronts. Lustron houses, constructed of prefabricated, 

enameled steel panels and intended for mass production, were 

introduced in the late 1940s in anticipation of the need for housing 

after the war. These houses were promoted for their low maintenance, in part because the walls, ceilings, and other interior surfaces 

were also enameled steel panels and easily washable. 

7
8

Glass 

For centuries, only blown cylinder and crown glass in small pieces 

was available and it was expensive. Thus, the glass in early windows 

in American buildings consisted of small panes which gradually 

increased in size over the years. With the invention of cast plate 

glass in 1848, large plates of glass could be manufactured which were 

strong and inexpensive. Plate glass was first used in the early 1850s 

as the primary exterior material (with a cast-iron framework) for 

such structures as international exhibition buildings, worlds’ fair 

pavilions, and greenhouses and conservatories. In the early 20th 

century, architects began using glass curtain walls in Art Modernestyle architecture and, most notably, the International Style. 

Tempered glass is a hardened or toughened glass which began to be 

used in building construction around 1940. By the middle of the 20th 

century, glass as a cladding system became synonymous with curtain 

wall systems. 

In addition to clear glass—flat or sometimes curved—there is also 

stained glass, tinted, patterned, textured, etched, frosted, leaded, 

painted, colored opaque glass and spandrel glass, prism glass, decorative Val de Verre glass (colored art glass), ceramic frit (pigmented 

glass enamel fused to a glass surface), and glass block. Many of 

these types of glass can be found in windows, transoms, doors and 

entrances, and storefront display windows, whereas some of them— 

especially opaque, pigmented structural glass with trade names such 

as Vitrolite, Carrara Glass, and Sani Onyx—are more likely to appear 

as exterior cladding on Art Deco-style or Art Moderne storefronts. 

Spandrel glass was first introduced on mid-20th-century buildings, 

particularly in storefront and curtain wall systems. Glass was also 

used historically in skylights and monitors; in theater, hotel, and 

apartment building marquees and canopies; and as a component of 

lightning rods and weathervanes, address plates, and signage. 

Glass features on the interior of historic buildings include transoms, 

windows, privacy screens, office dividers, wall partitions for borrowed light in office corridors, teller windows in banks, ticket windows in train stations and movie theaters, doorknobs, light fixtures, 

mirrored wall inlay, and also, beginning in the latter part of the 20th 

century, wall mosaics. Pigmented structural glass can be found in 

bathrooms and some kitchens because of its sanitary qualities. 

Low-e (low emissivity) glass, which is primarily used in windows to 

minimize solar gain, was developed in the last quarter of the 20th 

century. Impact-resistant glass is another more-recently developed 

type of glass designed to withstand hurricane-force wind and which 

can also be installed as a blast-resistant security feature. 
Paint and Other Coatings 

Paints and paint-like coatings have been used on historic buildings 

in America as protective coatings and for decorative treatments. 

What is commonly considered to be paint is a liquid consisting of 

a pigment which makes it opaque and colors it, a binder or base 

to hold it together, and sometimes a vehicle to carry the pigment. 

Many historic paints contained lead in the form of lead white, 

included as a “concealing” pigment that provided opacity, although 

zinc oxide was also used as an alternative. Lead increased durability 

and prevented mold and mildew. Titanium dioxide was sometimes 

used as a substitute for lead in the early 20th century, but lead 

continued to be an ingredient in most paints until it was banned 

as a hazardous substance in the U.S. in 1978. Traditional paints 

had an oil base, usually linseed, and the earliest paint colors were, 

for the most part, derived from natural pigments. Like today, both 

glossy and flat (or matte-finish) paints were used historically on 

the exterior and the interior of a building. After 1875, factory-made 

paints were readily available. Masonry and wood stains are traditional coatings which also consist of a pigment, a solvent, and little, 

if any, binder. They have a flat finish and are transparent rather than 

opaque so that the substrate is still visible. 

Other historic paints, such as whitewash, are water based and 

have a flat finish. In addition to water, whitewash is composed of 

hydrated (slaked) lime, salt, and various other materials and sometimes includes a natural pigment. Whitewash was used on interior 

plaster, in cellars, and on wood structural components, but not on 

wood doors, windows, or trim because its flat finish easily rubs off. 

Whitewash was also used on the exterior of brick or stone buildings, wood fences, and farm outbuildings as a protective coating. 

Often it was reapplied on an annual basis when it got dirty or if it 

wore off due to exposure to the weather. Calcimine (or kalsomine) 

and distemper paints were also water based and included natural 

glues, gelatin, gums, and whiting to which colored pigments could 

be added. They were used only on the interior and usually on 

plaster surfaces. Casein is a milk-based paint composed of hydrated 

lime, pigment, often oil, and a variety of additives to increase its 

durability. It was used on both the exterior and the interior of 

buildings. 

The interiors of historic buildings can exhibit a multitude of decorative painted treatments. Marbleized and grained finishes were 

applied to wood, stone, and plaster to give them the appearance 

of more exotic and costly materials. Other interior painted treatments, such as murals and stencils, are purely decorative. Tempera 

and gouache are traditional water-based paints used almost exclusively for decorative painting. 

Experimentation that began early in the 20th century resulted in 

the development of acrylic water-based paint, commonly known 

as latex paint. Oil-based/alkyd paint continues to be used in the 

21st century and is still preferred for certain applications. Latex 

paint tends to be more popular not only because it is water-based 

(making clean up easy during and after painting), but it also has 

fewer toxic vapors and, like solvent-based oil/alkyd paints, is very 

durable. 

Varnish, which is used primarily on interior wood features but also 

on exterior entrance doors, is another traditional coating. Unlike 

paint, varnish is transparent, composed of a resin, a drying oil, and 

a solvent. It has a glossy finish, which dulls over time. 

9
10

Composite Materials: Plastic, Resin, 

and Vinyl; Fiber-Reinforced Cement 

Siding; Fiberboard; and Floor 

Coverings 

Plastic is a malleable material composed of synthetic 

or natural organic materials made from various 

organic polymers, such as polyethylene and polyvinyl 

chloride (PVC), which can be poured into molds or 

rolled in sheets. It is generally agreed that the term 

plastic was introduced into popular usage in 1907 to 

describe the first fully synthetic plastic. Improved 

plastics were available in America by World War I. 

Production soared during World War II because 

plastics were needed to make up for the shortage of 

other materials. In mass production by the 1950s, the 

industry continued to expand with the development 

of increasingly more sophisticated plastics. 

Vinyl siding came on the market in the late 1950s, 

and its use, primarily in residential construction, 

increased as the product improved over the years. Coating canvas 

awnings with vinyl helped to extend their lifespan, evolving, eventually, into awnings manufactured solely of vinyl. Plastic signs on 

the exterior of historic commercial buildings changed and radically 

expanded the role of signage as advertising as well as being important design features themselves. Plastic was used sometimes for 

decorative trim on storefronts. Vinyl-coated wallpaper was used as 

early as the 1920s and is still selected for restaurants, commercial 

spaces, and hospitals because it is durable and washable. Other 

plastic materials became popular in the 1950s in the form of plasticlaminate sheeting and wall tiles. 

Fiber-reinforced plastic (FRP), is made of a polymer matrix mixed 

with fiber, usually fiberglass, to add strength; it is noted for its ability 

to be molded in thin shells. FRP is sometimes used as a substitute 

material to recreate missing or deteriorated architectural features in 

historic buildings. Acrylic plastic is a transparent synthetic plastic, 

generally identified by one of its trade names—Plexiglass or Lucite— 

which was patented in the 1950s as an alternative to glass. Foamed 

polystyrene, better known as Styrofoam, was first used in the mid1950s as building insulation. 

Fiber-Reinforced Cement Siding is a composite material made of 

sand, cement, and cellulose fibers. It was developed in the latter part 

of the 20th century as a less-hazardous replacement for asbestos 

cement siding, which preceded it, and was used for siding and roofing shingles from the early 20th century to the 1970s. Fiber-reinforced cement siding is frequently installed in the form of horizontal 

boards or vertical panels as exterior siding. Fiber-reinforced cement 

is used on both residential and commercial buildings. 

Fiberboard is a composite hardboard material made from pressuremolded wood fibers. It had early precedents in the late 18th century, 

but was first manufactured in large quantities in the 1920s, with its 

use expanding in the 1930s and 40s. Fiberboard (or wallboard, as 

it is commonly known) was marketed by various companies, such 

as Masonite. It was used as sheathing for roofing and siding on the 

exterior, for insulation, and for interior walls. 

The first composite floor covering was Linoleum, made from oxidized linseed oil and ground cork or wood flour. Its manufacture in 

the U.S. began in the late 19th century, about the same time synthetic rubber floor tile was also introduced. Asphalt floor tiles were 

first used in the 1920s and remained popular into the 1950s. Plastic/ 

vinyl replaced asphalt as a binder in floor tiles in the late 1920s, in 

part because plastic, unlike asphalt, could be made in lighter colors 

and a greater variety of colors. Semi-flexible vinyl flooring, manufactured in the form of tiles or rolled sheets, was developed by the 

1930s. After the war, it became more affordable and frequently was 

chosen for both residential and commercial interiors. 
Imitative Materials 

Imitative building materials are generally common and readily available materials used to simulate a more expensive material. They 

have a long history in American building construction. Wood, cut 

and planed and sometimes coated with a sand paint, has been used 

since the 18th century to replicate cut blocks of stone and quoins on 

the exterior of a building. Stucco, applied over any kind of construction (from log to rubble masonry) and scored to resemble stone, 

could make even a log house look elegant. Cast iron and pressed 

metal, whether as a complete façade, a storefront, or an individual 

feature such as a window hood, cornice, or decorative pilaster, were 

also used on the exterior of buildings to replicate stone. Not only 

architectural terra cotta, but cast stone served as a substitute for 

stone. Metal and concrete roofing tiles were used as less-costly alternatives to clay roofing tiles. 

In the 20th century, the use of exterior imitative materials expanded 

as new products were developed. Asphalt roll siding that resembled 

brick could be applied to a wood building, and asbestos composite 

shingles were produced to replace not only wood shingle siding, 

but also slate roofing shingles. Aluminum siding has been used as a 

replacement for wood siding, followed by vinyl siding, pressed wood 

siding, and, more recently, composite or fiber-cement siding. Manufactured faux slate roofing became popular because it costs less than 

slate and is lighter weight. Over the years, imitative materials have 

increased in variety as synthetic materials continue to be introduced, including a substitute, an exterior insulation and finish system 

(EIFS), for another imitative material—stucco. Imitative materials 

are also used to recreate missing or deteriorated architectural features in historic buildings. 

On the interior, imitative materials, such as scored plaster, were historically applied to walls to give the appearance of stone. Painted or 

marbleized finishes on plaster or wood could further simulate stone, 

and decorative graining could transform the surface of a common 

wood into a more exotic species. Scagliola, which is often applied to 

brick columns, is a very old technique that uses a plaster-like composite material to simulate marble. Lincrusta, an embossed wall covering, was developed 

in the late 19th century to simulate pressed metal. Embossed wall coverings continue to be 

produced in the 21st century. Concrete, vinyl, and other manufactured flooring materials are 

designed in many patterns and colors to replicate brick, stone, clay tile, and wood. 

11
12

Roofs 

The roof—with its form; features such as cresting, dormers, cupolas, and chimneys; and the size, color, and patterning of the roofing 

material—is an important design element of many historic buildings. 

In addition, a weathertight roof is essential to the long-term preservation of the entire structure. Historic roofing reflects availability of 

materials, levels of construction technology, climate, and cost. 

Throughout all periods of American history, with only minor exception, wood has been used for roofing; despite the early use of many 

other materials, wood shingles remained the most common roofing 

material throughout much of the 19th century. Initially the species of 

wood used would have been specific to a region, but the quality and 

design of a building were usually the prime determinants in the way 

wood was used, ranging from wide, lapped boards to small, uniform, 

geometrically-shaped shingles. 

Clay tile was used at 

least in a limited way 

in the first settlements 

on the East coast and 

it was manufactured 

in America by the 

mid 17th century. The 

Spanish influence in 

the use of clay roofing tiles is apparent in 

buildings in the south, 

southwest, and western 

parts of the country. 

Slate was also an early 

roofing material, but it 

was imported until the 

end of the 18th century 

when the first slate 

quarry opened. Both 

slate and tile roofs 

provided fire protection, especially important in urban areas. The 

use of slate expanded quickly in the second half of the 19th century 

with the development of the railroads, and it remained a preferred 

roofing material until the middle of the 20th century. 

Lead and copper were the first metals used for roofing, later joined 

by zinc and iron in the beginning of the 19th century. Lead was used 

in the mid 19th century for flashing and sometimes for the roofs of 

bay windows, domed, or steeply-pitched sections of a larger roof, 

and steeples. Copper has continued in use for roofing, gutters, 

downspouts, and flashing. 

Painted iron was initially used in large sheets, but it was replaced 

with smaller sheets of iron plated with tin or terne—a lead-tin mix— 

which were a more successful roofing material. As plated iron and, 

later, steel became widely available, their light weight, fire resistance, 

and low cost made them the ideal alternative to wood shingles. 

Galvanized metal—base steel coated with an alloy of zinc—gained 

widespread popularity in the 20th century. Galvanizing not only 

protects metal from rusting, but it also adds strength; corrugated 

sheet metal, when galvanized, became the preferred metal roofing 

material because it reduced the need for sheathing. Galvanized steel 

also could be stamped into sheets simulating shingles and clay tiles. 

In the late 19th century, concrete roofing tiles began to be produced 

as a substitute for clay tiles. At about the same time, composition 

roofing (built-up or roll roofing) was developed. This is a layered 

assembly of felt sheets and coal tar or asphalt, topped with gravel 

that is suitable for waterproofing flat and low-sloped roofs. Shortly 

after the start of the 20th century, asbestos fiber cement and asphalt 

shingles came into use as less-expensive alternatives to slate. Later 

in the 20th century, sheets of modified bitumen and synthetic rubber 

provided more options for a flat roof. By the end of the 20th century, 

liquid and vinyl membranes were also installed on flat roofs, and 

synthetic recycled materials were used increasingly for both new and 

replacement roofs. 
Windows 

Technology and prevailing architectural styles shaped the history of 

windows in America. The earliest windows were essentially medieval in their form. Small panes of glass, usually diamond-shaped 

and held together with lead, were set in a hinged casement sash of 

wood or iron. By the beginning of the 18th century, the glass had 

increased in size and had become rectangular, with putty holding it 

in place. Wood muntins replaced lead cames between the panes, and 

two sashes were placed in a frame where the lower one could slide 

vertically. Such simple windows remained common in utilitarian 

buildings well into the 20th century. With the introduction of iron 

pulleys, the sash could be hung from cords connected to counterweights, which resulted in single-hung windows, or double hung 

when both sashes were counterbalanced. 

Sash increased in depth as it evolved, providing additional strength 

that allowed narrower muntins. As the production of glass (blown 

initially as a disk and later as a cylinder) improved, larger pieces 

of glass became more affordable, resulting in fewer panes of glass 

in a window. A sash that would have had twelve panes of glass in 

the 18th century often had only two by the mid 19th century. After 

about 1850, with the advent of mass-produced millwork, standard 

profiles and sizes of windows were established with a wide variety 

of designs and glazing configurations that could be purchased from 

catalogues. The Chicago window, which featured a large fixed pane 

of glass in the center with a narrow, double-hung, operable sash 

window on either side of it, was introduced in the last decades of the 

19th century as a feature of the Chicago School-style of architecture. 

The picture window, popular in ranch-style houses in the mid 20th 

century, evolved from this. 

Steel was employed beginning at the end of the 19th century to 

build fire-resistant windows in tight urban environments. These 

hollow-core windows were frequently galvanized. Windows with 

solid, rolled steel sections were first produced in the first decade 

of the 20th century in many forms, ranging from casements (especially popular in domestic construction) to large, multi-pane units 

that provided whole walls of natural light in 

industrial and warehouse buildings. Operable vents in these large windows pivoted on 

simple pins. Their relatively small panes and 

the fact that they were puttied in from the 

interior made the inevitable breakage easy 

and inexpensive to repair. Rolled steel was 

also used for double-hung windows, which 

were common in high-rise buildings in the 

1920s and beyond. Aluminum windows were 

developed in the 1930s and, by the 1970s, 

rivaled wood in popularity, particularly in 

commercial and institutional buildings. They 

were produced in a variety of styles and 

functionality, including casement, hopper, 

awning, and double-hung sash. 

Metal-clad (initially copper) wood windows 

appeared early in the 20th century but 

were not common until the later part of the 

century, when enameled aluminum cladding 

replaced copper. Although used primarily 

as replacements in older buildings, vinyl 

windows were developed in the latter part of the 20th century and 

marketed as inexpensive and thermally efficient. Modern windows 

are also made of fiberglass and polymer-based composites. 

Storm windows were used historically and are still used to help 

regulate interior temperatures. Limited commercial use of thermalpane or insulated glass in windows began in the 1930s, but it was not 

readily available until about 1950. Tempered glass also came into 

use about this time. Since then, work has continued to improve its 

efficiency and to reduce the effect of ultra-violet rays with tinted and 

low-e (low emissivity) glass. Impact-resistant glass is not new, but 

its use in windows continues to expand to meet modern hurricane 

code requirements as well as protection and security requirements. 

13
14

Entrances and Porches 

Entrances and porches are often the focus of historic American 

buildings. With their functional and decorative features (such as 

doors, steps, balustrades, columns, pilasters, and entablatures), they 

can be extremely important in defining the historic character of a 

building. In many cases, porches were also energy-saving features 

and remain so today, shading southern and western elevations. Usually, entrances and porches were integral components of a historic 

building’s design; for example, porches on Greek Revival houses, 

with pediments and Doric or Ionic columns, echoed the architectural elements and features of the building itself. Center, single-bay 

porches or arcaded porches are evident in Italianate-style buildings 

of the 1860s. Doors of Renaissance Revival-style buildings frequently 

featured entablatures or pediments. Porches characterized by latheturned porch posts, railings, and balusters were especially prominent 

and decorative features of Eastlake, Queen Anne, and Stick-style 

houses. Deep porches on bungalows and Craftsman-style houses 

of the early 20th century feature tapered posts, exposed posts and 

beams, rafter tails, and low-pitched roofs with wide overhangs. 

Late 19th- and early 20th-century high-rise buildings are often 

distinguished by highly-ornamented entrances, some with revolving 

doors, which were introduced around the turn of the 20th century. 

Some commercial structures in the early- to mid-20th century have 

recessed entrances with colorful terrazzo flooring. Entrances to 

Art Deco-style residential and commercial buildings often feature 

stylized glass and stainless-steel doors with geometric designs. 

Entrances on modernist buildings may have simple glazing and, 

frequently, projecting concrete or metal canopies. 

Porches can have regional variations, not only in style, but also in 

nomenclature. For instance, in Hawaii, lanai is used to describe a 

type of porch which might be known as a veranda in some parts of 

the South, a piazza in Charleston, or a gallery in New Orleans. 
Storefronts 

The storefront is often the most prominent feature of a historic 

commercial building, playing a crucial role in a store’s advertising 

and merchandising strategy. The earliest storefronts in America, 

dating from the late 18th and early 19th centuries, had small, 

residential-style windows with limited display space. A few featured oriel windows or glass vitrine cases (sometimes added later) 

that projected out from the façade. Early storefront systems were 

frequently wood. In the 19th century, storefront display windows 

progressively increased in size as plate glass became available in 

larger units. This reflected the fact that cast-iron columns and lintels 

were thinner, allowing larger sheets of glazing that became available 

at about the same time. In some regions, storefronts and the entire 

building façade were constructed entirely of cast iron, later followed 

by galvanized metal, copper, bronze, and aluminum. 

Historic storefront systems have many different configurations: 

they may have multiple entrance doors (including one to access an 

upstairs apartment if one exists); they may be symmetrical or asymmetrical; and entrances may be flush or recessed from the shop’s 

windows. Transoms, sometimes with prism glass, are often a component of storefronts. In the 19th century, awnings added another 

feature to the storefront. Permanent metal canopies attached to 

the façade or supported by free-standing posts or columns, as well 

as retractable canvas awnings, provided shelter for customers and 

merchandise alike. As the 20th century progressed, new storefront 

designs were introduced, some with deeply recessed entrances with 

expanded display cases or “floating display islands.” In the 1920s, 

1930s, and later, structural pigmented glass such as Carrara Glass, 

Vitrolite, and Sani Onyx; aluminum and stainless steel; porcelain 

enamel; glass block; neon signs; and other new materials were 

introduced in Art Deco-style and Art Moderne storefronts. Modular 

storefront systems were introduced after World War II. 

Storefronts are typically altered more than any other building feature to reflect the latest architectural styles and appear up-to-date 

to attract customers. Older storefronts were often remodeled with 

a new design and materials by installing pigmented structural glass, 

for instance, and other 20th-century materials. These altered storefronts may have acquired significance in their own right and, in this 

case, should be retained. 

15
16

Curtain Walls 

Curtain wall construction was originally based on a steel framework. 

Today, most curtain wall construction utilizes an extruded aluminum framework, which became popular in the 1930s in the U.S. and 

came into its own after World War II. A curtain wall is not a structural system and, although it is self supporting, does not carry the 

weight of the building. Rather, it is an exterior wall hung or attached 

to the structural system. Curtain wall construction most frequently 

employs glass, metal panels, thin stone veneer, and other cladding 

materials, although louvers and vents, like glass panels, can also 

be set into the metal framework. Newer curtain wall systems may 

incorporate rain screens and glass fiber reinforced concrete panels 

(GFRC). Because curtain wall construction uses relatively lightweight and less expensive materials, it reduces building costs, which, 

in part, explains its popularity. 

There are essentially two types of curtain wall systems: stick systems 

and unitized or modular systems. A stick system is a framing system 

composed of long metal pieces (sticks) put together individually 

using vertical pieces (mullions) between floors and horizontal pieces 

between the vertical members. The framing members may sometimes be assembled in a factory, but the installation and glazing is 

done on site. A unitized or modular curtain wall system consists of 

ready-to-hang, pre-assembled modules which already include glazing 

or other panel infill. These modular units are usually one story in 

height and approximately five- to six-feet wide. Both types of curtain 

walls are attached to floor slabs or columns with field-drilled bolts in 

mated, adjustable anchor brackets. 

Glass panels in curtain wall systems can be fixed or operable and can 

include spandrel glass, clear, or tinted glass. Stone veneer panels may 

be slate, granite, marble, travertine, or limestone. Metal panels can 

be aluminum plate, stainless steel, copper, or other non-corrosive 

types of metal. Other materials used in curtain wall systems include 

composite panels (such as honeycomb composite panels, consisting 

of two thin sheets of aluminum bonded to a thin plastic layer or rigid 

insulation in the middle); architectural terra cotta; glazed ceramic 

tile; and fiber-reinforced plastic (FRP). 
Structural Systems 

Numerous types of structural systems 

have been employed in the construction 

of buildings throughout American history. 

Some systems and building methods 

overlapped, and many remained in 

use for years. These systems—listed 

according to the period when they were 

first introduced—include but are not 

limited to: wood-frame construction 

(17th century), load-bearing masonry 

construction (18th century), balloonframe construction (19th century), brick 

cavity-wall construction (19th century), 

heavy-timber post and beam industrial 

construction (19th century), fireproof 

iron construction (19th century), heavy 

masonry and steel construction (19th 

century), skeletal steel construction (19th 

century), light frame and veneer brick 

construction (20th century), and cast-inplace concrete, concrete block, and slab and 

post construction (20th century). 

Exposed iron and steel structural systems 

are character defining in many utilitarian 

and industrial structures of the late 19th 

and early 20th centuries that have large open interior spaces, such as 

train sheds and armories. Exposed wood structural systems became 

an important interior decorative element during the Arts and Crafts 

period and in Craftsman-style bungalows in the early 20th century. 

Exposed cast-concrete structural systems and system components 

define the character of many industrial interiors and, later, other 

interior spaces in 20th-century buildings. 

If features of the historic structural system are exposed (such as 

load-bearing brick walls, cast-iron columns, roof trusses, posts and 

beams, vigas, and outriggers, or masonry foundation walls), they 

are likely to be important in defining the building’s overall historic 

character. A concealed structural system, although not character 

defining, may still be significant as an example of historic building 

technology. 

17
18

Mechanical Systems 

Mechanical, lighting, and plumbing systems improved significantly 

with the onset of the Industrial Revolution. The 19th-century interest in hygiene, personal comfort, and reducing the spread of disease 

resulted in the development of central heating, piped water, piped 

gas, and networks of underground cast-iron sewers in urban areas. 

The mass production of cast-iron radiators made central heating 

affordable to many. By the turn of the 20th century, it was common 

for heating, lighting, and plumbing to be an integral part of most 

buildings. 

The increasing availability of electricity as the 20th century progressed had a tremendous effect on the development of mechanical 

systems and opened up a new age of technology. Electric lighting 

brightened the interiors of all types of buildings, as well as building exteriors, their sites, and settings. Electricity not only improved 

heating systems, but in the 1920s it also brought central air conditioning to movie theaters and auditoriums, where it was first 

installed. By the middle of the 20th century, forced-air systems 

provided both heat and cooling in many buildings. In the late 20th 

century, as HVAC systems increased in efficiency, they decreased in 

size, with smaller components, such as split ductless systems with 

wall-mounted air handlers, cassette ceiling-mounted diffusers, or 

high-velocity mini duct systems. These systems can be especially 

useful for retrofitting historic buildings because they are small and 

unobtrusive. Heat pumps, another late-20th century invention, can 

help to supplement existing HVAC systems. 

Replacing hydraulic elevators, which were invented in the mid-19th 

century, with electric elevators in the early decades of the 20th 

century resulted in a boom in the construction of taller high-rise 

buildings and skyscrapers. Escalators, also invented in the mid 

19th century, became more and more common as the 20th century 

advanced. By the latter part of the century, moving walkways helped 

facilitate travelers’ passage from one place to another in transportation centers, such as airports. 

The visible decorative features that remain of historic mechanical 

systems (such as grilles, lighting fixtures, elevator doors, and escalators) themselves may contribute to the overall historic character of 

the building and should be retained when feasible. Reusing an existing, functioning system and upgrading it as needed, should always 

be considered when feasible. However, because a mechanical system 

needs to work efficiently, most historic or older systems will likely 

need to be replaced to meet modern requirements. 
INTERIOR SPACES, FEATURES,

AND FINISHES 

Spaces 

The earliest buildings in America were very basic and likely to have 

only one or, perhaps, two rooms. As communities became more 

established and prosperous, buildings—houses in particular— 

increased in size, and construction became more elaborate and 

sophisticated, reflecting the wealth and tastes of individual owners. 

Larger buildings inevitably included multiple rooms designed to 

accommodate a variety of purposes. Thus, the interior floor plan, 

the arrangement and sequence of spaces, and built-in features 

and applied finishes are individually and collectively important in 

defining the historic character of the building. With the exception 

of most historic utilitarian buildings, manufacturing and industrial 

buildings, garages, and maintenance facilities, interiors are typi­

cally composed of a series of primary and secondary spaces. This 

succession of spaces is applicable to many historic buildings, from 

courthouses to cathedrals to cottages and commercial structures. 

Primary spaces, including entrance halls, lobbies, double parlors, 

living rooms, corridors, and assembly spaces, are defined not only 

by their function, but also by their location, features, finishes, size, 

and proportion. 

Secondary spaces in historic interiors are generally more functional 

than decorative and, depending on the building’s use, may include 

kitchens, bathrooms, utility rooms, attics, basements, mail rooms, 

rear hallways, and most office spaces. Although these spaces were 

important to how the building functioned historically, they are 

generally less significant than primary spaces and, thus, are usually 

the most appropriate places to make changes which may be neces­

sary in a historic building, such as those required to meet code or to 

install mechanical equipment. The traditional sequence of interior 

spaces in late 19th- through early 20th-century high-rise build­

ings went from public areas (such as the lobby) on the first floor 

19
20

and corridors on upper floors to the private spaces behind them 

(i.e., offices, apartments, or hotel rooms). This hierarchy of spaces 

continues to define the historic character of many high-rise buildings. However, in commercial structures built on speculation with 

open floor plans, the upper floors, especially, are likely to have been 

reconfigured many times. In some cases, these interiors may have 

little historic character but, in others, the spaces and their appearance may have acquired significance because of a specific tenant, use 

(such as a boardroom or executive office), or an event. 

Features and Finishes 

Historic character-defining features and finishes can range from very 

elaborate to very simple and plain, or from formal to utilitarian. The 

interior features that are important to a particular building generally reflect its original or historic use. Thus, the interior features and 

finishes of industrial and factory buildings are basic and practical, 

with exposed structural systems; wood, brick, or concrete walls 

and floors; large windows or monitors with clerestory windows to 

provide natural light; and minimal or no door and window surrounds. Commercial, office, hotel, and high-rise apartment buildings have public spaces that often include highly-decorated lobbies, 

elevator lobbies with marble flooring, wood or marble wainscoting 

in the upper corridors and, particularly in office buildings, offices 

separated from hallways by heavy doors with glass transoms and 

glass wall partitions for borrowed light. The repetitive pattern itself 

of the corridors on the upper floors in these multi-story buildings is 

also often significant in defining their historic character. Individual 

historic residential structures frequently have painted plaster walls 

and ceilings, door and window trim, fireplaces with mantels, wood 

flooring, and a staircase if the house has more than one story. Some 

mid-to late-20th-century houses that are less traditional in design 

have simpler and less-ornamented interiors. 

Building Site 

The building site consists of a historic building or buildings, structures, and associated landscape features and their relationship 

within a designed or legally-defined parcel of land. A site may be 

significant in its own right or because of its association with the 

historic building or buildings. 
Setting (District/Neighborhood) 

The setting is the larger area or environment in which a 

historic building is located. It may be an urban, suburban, 

or rural neighborhood or a natural landscape in which 

buildings have been constructed. The relationship of 

buildings to each other, setbacks, fence patterns, views, 

driveways and walkways, and street trees and other 

landscaping together establish the character of a district 

or neighborhood. 

21
22

Special Requirements: Code-Required Work 

Sensitive solutions to meeting code requirements are an important part 

of protecting the historic character of the building. Thus, work that must 

be done to meet accessibility and life-safety requirements must always be 

assessed for its potential impact on the historic building. 

Accessibility 

It is often necessary to make modifications to a historic building 

to make it compliant with accessibility code requirements. Federal 

rules, regulations, and standards provide guidance on how to make 

historic buildings accessible. Work must be carefully planned and 

undertaken in a manner that results in minimal or no loss of historic 

exterior and interior character-defining spaces, features, or finishes. 

The goal should be to provide the highest level of access with the 

least impact to the historic building. 
Life Safety 

When undertaking work on historic buildings, it is also necessary to 

consider the impact that meeting life-safety codes (public health, 

occupational health, life safety, electrical, seismic, structural, and 

building codes) will have on both exterior and interior spaces, features, and finishes. Historic building materials that are hazardous, 

such as lead paint and asbestos, will require abatement or encapsulation. Some newer life-safety codes are more flexible and allow 

greater leniency for historic buildings when making them code compliant. It is also possible that there may be an alternative approach 

to meeting codes that will be less damaging to the historic building. 

Coordinating with code officials early in project planning will help 

ensure that code requirements can be met in a historic building 

without negatively impacting its character. 

23
24

Resilience to Natural Hazards 

The potential future impacts of natural hazards on a historic building 

should be carefully evaluated and considered. If foreseeable loss, 

damage, or destruction to the building or its features can be reasonably anticipated, treatments should be undertaken to avoid or 

minimize the impacts and to ensure the continued preservation of 

the building and its historic character. In some other instances, the 

effects may be minimal or more gradual and the impacts unknown or 

not anticipated to affect the property until sometime in the future. In 

all instances, a building should be maintained in good condition and 

monitored regularly, and historic documentation should be prepared 

as a record of the building and to help guide future treatments. 

Some impacts of natural hazards may be particularly sudden and 

destructive to a historic building (such as riverine flash flooding, 

coastal storm surge, an earthquake, or a tornado) and may require 

adaptive treatments that are more invasive. When a treatment is 

proposed for a building that addresses such potential impacts and 

will affect the building’s historic character, other feasible alternatives 

that would require less change should always be considered first. In 

some instances, a certain degree of impact on a building’s historic 

character may be necessary to ensure its retention and continued 

preservation. In other instances, a proposed treatment may have too 

great an impact to preserve the historic character of the building. A 

historic building may have existing characteristics or features that 

help to address or minimize the impacts of natural hazards. Some 

historic buildings may have been altered previously or be in regions 

where it has been traditional to adapt buildings frequently subject 

to damage from natural hazards, such as flooding. All these factors 

should be taken into consideration when 

planning preventive treatments. The goal 

should always be to minimize the impacts to 

the building’s historic character to the greatest extent possible in adapting the building to 

be more resilient. 
Sustainability 

Before implementing any energy improvements to enhance the 

sustainability of a historic building, the existing energy-efficient 

characteristics of the building should be evaluated. Historic building construction methods and materials often maximized natural 

sources of heating, lighting, and ventilation to respond to local 

climatic conditions. The key to a successful project is to identify and 

understand any lost original and existing energy-efficient aspects of 

the historic building, as well as to identify and understand its character-defining features to ensure they are taken into account. The 

most sustainable building may be one that already exists. Thus, good 

preservation practice is very often synonymous with sustainability. 

There are numerous treatments—traditional as well as new technological innovations—that may be used to upgrade a historic building 

to help it operate more efficiently while retaining its character. 

The topic of sustainability is addressed in detail in The Secretary of the 

Interior’s Standards for Rehabilitation & Illustrated Guidelines on Sustainability for Rehabilitating Historic Buildings. Although specifically developed for the treatment Rehabilitation, the Sustainability Guidelines 

can be used to help guide the other treatments. 

25
26

New Exterior Additions and Related New 

Construction 

A new exterior addition to a historic building should be considered 

in a rehabilitation project only after determining that requirements 

for a new or continuing use cannot be successfully met by altering non-significant interior spaces. If the existing building cannot 

accommodate such requirements in this way, then an exterior addition or, in some instances, separate new construction on a site may 

be acceptable alternatives. 

A new addition must preserve the building’s historic character, form, 

significant materials, and features. It must be compatible with the 

massing, size, scale, and design of the historic building while differentiated from the historic building. It should also be designed and 

constructed so that the essential form and integrity of the historic 

building would remain if the addition were to be removed in the 

future. There is no formula or prescription for designing a compatible new addition or related new construction on a site, nor is there 

generally only one possible design approach that will meet the 

Standards. 

New additions and related new construction that meet the Standards can be any architectural style—traditional, contemporary, or 

a simplified version of the historic building. However, there must be 

a balance between differentiation and compatibility to maintain the 

historic character and the identity of the building being enlarged. 

New additions and related 

new construction that are 

either identical to the historic 

building or in extreme contrast to it are not compatible. 

Placing an addition on the 

rear or on another secondary elevation helps to ensure 

that it will be subordinate 

to the historic building. 

New construction should 

be appropriately scaled and 

located far enough away from 

the historic building to maintain its character and that of 

the site and setting. In urban 

or other built-up areas, new 

construction that appears as 

infill within the existing pattern of development can also 

preserve the historic character of the building, its site, 

and setting. 
PRESERVATION PRESERVATION

STANDARDS FOR PRESERVATION & GUIDELINES 

FOR PRESERVING HISTORIC BUILDINGS 

Preservation
 

Preservation is defined as the act or process of applying measures necessary to sustain the existing form, integrity, and materials of an historic 

property. Work, including preliminary measures to protect and stabilize 

the property, generally focuses upon the ongoing maintenance and repair 

of historic materials and features rather than extensive replacement and 

new construction. New exterior additions are not within the scope of this 

treatment; however, the limited and sensitive upgrading of mechanical, 

electrical, and plumbing systems and other code-required work to make 

properties functional is appropriate within a preservation project. 

27
PRESERVATION

28

Standards for Preservation 

1.	 A property will be used as it was historically, or be given a new use that maximizes the 

retention of distinctive materials, features, spaces and spatial relationships. Where a 

treatment and use have not been identified, a property will be protected and, if necessary, 

stabilized until additional work may be undertaken. 

2.	 The historic character of a property will be retained and preserved. The replacement of 

intact or repairable historic materials or alteration of features, spaces and spatial relationships that characterize a property will be avoided. 

3.	 Each property will be recognized as a physical record of its time, place and use. Work 

needed to stabilize, consolidate and conserve existing historic materials and features will 

be physically and visually compatible, identifiable upon close inspection and properly 

documented for future research. 

4.	 Changes to a property that have acquired historic significance in their own right will be 

retained and preserved. 

5.	 Distinctive materials, features, finishes and construction techniques or examples of 

craftsmanship that characterize a property will be preserved. 

6.	 The existing condition of historic features will be evaluated to determine the appropriate 

level of intervention needed. Where the severity of deterioration requires repair or limited replacement of a distinctive feature, the new material will match the old in composition, design, color and texture. 

7.	 Chemical or physical treatments, if appropriate, will be undertaken using the gentlest 

means possible. Treatments that cause damage to historic materials will not be used. 

8. Archeological resources will be protected and preserved in place. If such resources must be 

disturbed, mitigation measures will be undertaken. 
PRESERVATION

 

GUIDELINES FOR PRESERVING HISTORIC BUILDINGS 

INTRODUCTION 

Preservation is the appropriate treatment when the objective of the 

project is to retain the building as it currently exists. This means 

that not only the original historic materials and features will be preserved, but also later changes and additions to the original building. 

The expressed goal of the Standards for Preservation and Guidelines for Preserving Historic Buildings is retention of the building’s existing form, features, and materials. This may be as simple 

as maintaining existing materials and features or may involve more 

extensive repair. Protection, maintenance, and repair are emphasized while replacement is minimized. 

Identify, Retain, and Preserve Historic 

Materials and Features 

The guidance for the treatment Preservation begins with recommendations to identify the form and detailing of those architectural 

materials and features that are important in defining the building’s 

historic character and which must be retained to preserve that character. Therefore, guidance on identifying, retaining, and preserving 

character-defining features is always given first. 

Stabilize Deteriorated Historic Materials and 

Features as a Preliminary Measure 

Deteriorated portions of a historic building may need to be protected through preliminary stabilization measures until additional 

work can be undertaken. Stabilizing may begin with temporary 

structural reinforcement and progress to weatherization or correcting unsafe conditions. Although it may not be necessary in every 

preservation project, stabilization is nonetheless an integral part 

of the treatment Preservation; it is equally applicable to the other 

treatments if circumstances warrant. 

Protect and Maintain Historic Materials and 

Features 

After identifying those materials and features that are important 

and must be retained in the process of Preservation work, then 

protecting and maintaining them are addressed. Protection generally 

involves the least degree of intervention and is preparatory to other 

work. Protection includes the maintenance of historic materials and 

features as well as ensuring that the property is protected before and 

during preservation work. 

Repair (Stabilize, Consolidate, and Conserve) 

Historic Materials and Features 

Next, when the physical condition of character-defining materials and 

features warrants additional work, repairing by stabilizing, consolidating, and conserving is recommended. The intent of Preservation is to 

retain existing materials and features while introducing as little new 

material as possible. Consequently, guidance for repairing a historic 

material, such as masonry, begins with the least degree of intervention possible, such as strengthening materials through consolidation, 

when necessary, or repointing with mortar of an appropriate strength. 

Repairing masonry, as well as wood and metal features, may include 

patching, splicing, or other treatments using recognized preservation 

methods. All work should be physically and visually compatible. 

INTRODUCTION 29
PRESERVATION

30

Limited Replacement in Kind of Extensively 

Deteriorated Portions of Historic Features 

The greatest level of intervention in this treatment is the limited 

replacement in kind of extensively deteriorated or missing components of features when there are surviving prototypes or when the 

original features can be substantiated by documentary and physical 

evidence. The replacement material must match the old, both physically and visually (e.g., wood with wood). Thus, with the exception 

of hidden structural reinforcement, such as steel rods, substitute 

materials are not appropriate in the treatment Preservation. If 

prominent features are missing, such as an interior staircase or an 

exterior cornice, then a Rehabilitation or Restoration treatment may 

be more appropriate. 

Code-Required Work: 

Accessibility and Life Safety 

These sections of the Preservation guidance address work that must 

be done to meet accessibility and life-safety requirements. This work 

may be an important aspect of preservation projects, and it, too, 

must be assessed for its potential negative impact on the building’s character. For this reason, particular care must be taken not to 

obscure, damage, or destroy character-defining materials or features 

in the process of undertaking work to meet code requirements. 

Resilience to Natural Hazards 

Resilience to natural hazards should be addressed as part of a Preservation project. A historic building may have existing characteristics 

or features that help to address or minimize the impacts of natural 

hazards. These should always be used to best advantage when planning new adaptive treatments so as to have the least impact on the 

historic character of the building, its site, and setting. 

Sustainability 

Sustainability should be addressed as part of a Preservation project. 

Good preservation practice is often synonymous with sustainability. 

Existing energy-efficient features should be retained and repaired. 

New sustainability treatments should generally be limited to updating existing features and systems so as to have the least impact on 

the historic character of the building. 

The topic of sustainability is addressed in detail in The Secretary of 

the Interior’s Standards for Rehabilitation & Illustrated Guidelines on 

Sustainability for Rehabilitating Historic Buildings. Although specifically developed for the treatment Rehabilitation, the Sustainability 

Guidelines can be used to help guide the other treatments. 

Preservation as a Treatment. When the property’s distinctive materials, features, and spaces are essentially intact and thus convey the historic 

significance without extensive repair or replacement; when depiction at 

a particular period of time is not appropriate; and when a continuing or 

new use does not require additions or extensive alterations, Preservation 

may be considered as a treatment. Prior to undertaking work, a documentation plan for Preservation should be developed. 

INTRODUCTION 
PRESERVATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving masonry features that are 

important in defining the overall historic character of the building (such as walls, brackets, railings, cornices, window and door 

surrounds, steps, and columns) and decorative ornament and 

other details, such as tooling and bonding patterns, coatings, and 

color. 

Altering masonry features which are important in defining the 

overall historic character of the building so that, as a result, the 

character is diminished. 

Replacing historic masonry features instead of repairing or replacing 

only the deteriorated masonry. 

Applying paint or other coatings (such as stucco) to masonry that 

has been historically unpainted or uncoated. 

Removing paint from historically-painted masonry. 

Stabilizing deteriorated or damaged masonry as a preliminary 

measure, when necessary, prior to undertaking preservation work. 

Failing to stabilize deteriorated or damaged masonry until additional 

work is undertaken, thereby allowing further damage to occur to the 

historic building 

Protecting and maintaining masonry by ensuring that historic 

drainage features and systems that divert rainwater from masonry 

surfaces (such as roof overhangs, gutters, and downspouts) are 

intact and functioning properly. 

Failing to identify and treat the causes of masonry deterioration, 

such as leaking roofs and gutters or rising damp. 

Cleaning masonry only when necessary to halt deterioration or 

remove heavy soiling. 

Cleaning masonry surfaces when they are not heavily soiled to 

create a “like-new” appearance, thereby needlessly introducing 

chemicals or moisture into historic materials. 

Carrying out masonry cleaning tests when it has been determined Cleaning masonry surfaces without testing or without sufficient time 

that cleaning is appropriate. Test areas should be examined for the testing results to be evaluated. 

to ensure that no damage has resulted and, ideally, monitored 

over a sufficient period of time to allow long-range effects to be 

predicted. 

[1] A test patch should 

always be done before 

using a chemical cleaner 

to ensure that it will 

not damage historic 

masonry, as in this 

instance, terra cotta. 

MASONRY 31
PRESERVATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Cleaning soiled masonry surfaces with the gentlest method possible, such as using low-pressure water and detergent and natural 

bristle or other soft-bristle brushes. 

Cleaning or removing paint from masonry surfaces using most 

abrasive methods (including sandblasting, other media blasting, or 

high-pressure water) which can damage the surface of the masonry 

and mortar joints. 

Using a cleaning or paint-removal method that involves water or 

liquid chemical solutions when there is any possibility of freezing 

temperatures. 

Cleaning with chemical products that will damage some types of 

masonry (such as using acid on limestone or marble), or failing to 

neutralize or rinse off chemical cleaners from masonry surfaces. 

Using biodegradable or environmentally-safe cleaning or paintremoval products. 

Using paint-removal methods that employ a poultice to which 

paint adheres, when possible, to neatly and safely remove old 

lead paint. 

Using coatings that encapsulate lead paint, when possible, where 

the paint is not required to be removed to meet environmental 

regulations. 

Allowing only trained conservators to use abrasive or laser-cleaning methods, when necessary, to clean hard-to-reach, highlycarved, or detailed decorative stone features. 

32 MASONRY 
PRESERVATION

 

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Removing damaged or deteriorated paint only to the next sound 

layer using the gentlest method possible (e.g., hand scraping) 

prior to repainting. 

Removing paint that is firmly adhered to masonry surfaces. 

Applying compatible paint coating systems to historically-painted 

masonry following proper surface preparation. 

Failing to follow manufacturers’ product and application instructions when repainting masonry features. 

Repainting historically-painted masonry features with colors that 

are appropriate to the building and district. 

Using paint colors on historically-painted masonry features that are 

not appropriate to the building or district. 

Protecting adjacent materials when working on masonry features. Failing to protect adjacent materials when working on masonry 

features. 

Evaluating the overall condition of the masonry to determine 

whether more than protection and maintenance, such as repairs 

to masonry features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

masonry features. 

Repairing masonry by patching, splicing, consolidating, or 

otherwise reinforcing the masonry using recognized preservation 

methods. 

Removing masonry that could be stabilized, repaired, and conserved, or using untested consolidants, improper repair techniques, 

or unskilled personnel, potentially causing further damage to 

historic materials. 

Repairing masonry walls and other masonry features by repointing the mortar joints where there is evidence of deterioration, 

such as disintegrating mortar, cracks in mortar joints, loose 

bricks, or damaged plaster on the interior. 

Removing non-deteriorated mortar from sound joints and then 

repointing the entire building to achieve a more uniform appearance. 

Removing deteriorated lime mortar carefully by hand raking the 

joints to avoid damaging the masonry. 

[2] Not Recommended: 

The use of inappropriate 

Portland cement mortar 

to repoint these soft 

19th-century bricks has 

caused some of them to 

spall. Photo: Courtesy 

Nebraska State Historic 

Preservation Office. 

MASONRY 33
PRESERVATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Using power tools only on horizontal joints on brick masonry in 

conjunction with hand chiseling to remove hard mortar that is 

deteriorated or that is a non-historic material which is causing 

damage to the masonry units. Mechanical tools should be used 

only by skilled masons in limited circumstances and generally 

not on short, vertical joints in brick masonry. 

Allowing unskilled workers to use masonry saws or mechanical tools 

to remove deteriorated mortar from joints prior to repointing. 

Duplicating historic mortar joints in strength, composition, color, 

and texture when repointing is necessary. In some cases, a limebased mortar may also be considered when repointing Portland 

cement mortar because it is more flexible. 

Repointing masonry units with mortar of high Portland cement content (unless it is the content of the historic mortar). 

Duplicating historic mortar joints in width and joint profile when Using “surface grouting” or a “scrub” coating technique, such as 

repointing is necessary. a “sack rub” or “mortar washing,” to repoint exterior masonry units 

instead of traditional repointing methods. 

Changing the width or joint profile when repointing. 

Repairing stucco by removing the damaged material and patching with new stucco that duplicates the old in strength, composition, color, and texture. 

Removing sound stucco or repairing with new stucco that is different in composition from the historic stucco. 

Patching stucco or concrete without removing the source of deterioration. 

Replacing deteriorated stucco with synthetic stucco, an exterior 

insulation and finish system (EIFS), or other non-traditional 

materials. 

Using mud plaster or a compatible lime-plaster adobe render, 

when appropriate, to repair adobe. 

Applying cement stucco, unless it already exists, to adobe. 

Sealing joints in concrete with appropriate flexible sealants and 

backer rods, when necessary. 

Repointing masonry units (other than concrete) with a synthetic 

caulking compound instead of mortar. 

34 MASONRY 
PRESERVATION

[3] Not Recommended: 

Cracks in the stucco 

have not been repaired, 

thereby allowing ferns 

to grow in the moist 

substrate which will 

cause further damage to 

the masonry. 

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Cutting damaged concrete back to remove the source of deterioration, such as corrosion on metal reinforcement bars. The new 

patch must be applied carefully so that it will bond satisfactorily 

with, and match, the historic concrete. 

Patching damaged concrete without first removing the source of 

deterioration. 

Using a non-corrosive, stainless-steel anchoring system when 

replacing damaged stone, concrete, or terra-cotta units that have 

failed. 

MASONRY 35
PRESERVATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing components 

of masonry features when there are surviving prototypes, such as 

terra-cotta brackets or stone balusters, or when the replacement 

can be based on documentary or physical evidence. The new 

work should match the old in material, design, scale, color, and 

finish. 

Replacing an entire masonry feature, such as a column or stairway, 

when limited replacement of deteriorated and missing components 

is appropriate. 

Using replacement material that does not match the historic 

masonry feature. 

Applying non-historic surface treatments, such as water-repellent 

coatings, to masonry only after repointing and only if masonry 

repairs have failed to arrest water penetration problems. 

Applying waterproof, water-repellent, or non-original historical coatings (such as stucco) to masonry as a substitute for repointing and 

masonry repairs. 

Applying permeable, anti-graffiti coatings to masonry when 

appropriate. 

Applying water-repellent or anti-graffiti coatings that change the 

appearance of the masonry or that may trap moisture if the coating 

is not sufficiently permeable. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

36 MASONRY 
PRESERVATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND OTHER FUNCTIONAL 

AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving wood features that are 

important in defining the overall historic character of the building 

(such as siding, cornices, brackets, window and door surrounds, 

and steps) and their paints, finishes, and colors. 

Altering wood features which are important in defining the overall 

historic character of the building so that, as a result, the character 

is diminished. 

Replacing historic wood features instead of repairing or replacing 

only the deteriorated wood. 

Changing the type of finish, coating, or historic color of wood features 

[4] Hand scraping 

to remove peeling 

paint from wood 

siding in preparation 

for repainting is an 

important part of 

regularly-scheduled 

maintenance. 

WOOD 37
PRESERVATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND OTHER FUNCTIONAL 

AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Stabilizing deteriorated or damaged wood as a preliminary measure, when necessary, prior to undertaking preservation work. Failing to stabilize deteriorated or damaged wood until additional 

work is undertaken, thereby allowing further damage to occur to the 

historic building. 

Protecting and maintaining wood features by ensuring that historic drainage features that divert rainwater from wood surfaces 

(such as roof overhangs, gutters, and downspouts) are intact and 

functioning properly. Finding and eliminating sources of moisture 

that may damage wood features, such as clogged gutters and 

downspouts, leaky roofs, or moisture-retaining soil that touches 

wood around the foundation. 

Failing to identify and treat the causes of wood deterioration, such 

as faulty flashing, leaking gutters, cracks and holes in siding, deteriorated caulking in joints and seams, plant material growing too 

close to wood surfaces, or insect or fungal infestation. 

Finding and eliminating sources of moisture that may damage 

wood features, such as clogged gutters and downspouts, leaky 

roofs, or moisture-retaining soil that touches wood around the 

foundation. 

Applying chemical preservatives or paint to wood features that are 

subject to weathering, such as exposed beam ends, outriggers, or 

rafter tails. 

Using chemical preservatives (such as creosote) which, unless they 

were used historically, can change the appearance of wood features. 

[5] Rotted wood shingles 

have been replaced in 

kind with matching wood 

shingles. 

38 WOOD 
PRESERVATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND OTHER FUNCTIONAL 

AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Implementing an integrated pest management plan to identify Stripping paint or other coatings from wood features without 

appropriate preventive measures to guard against insect damage, recoating. 

such as installing termite guards, fumigating, and treating with 

chemicals. Retaining coatings (such as paint) that protect the 

wood from moisture and ultraviolet light. Paint removal should be 

considered only when there is paint surface deterioration and as 

part of an overall maintenance program which involves repainting 

or applying other appropriate coatings 

Removing damaged or deteriorated paint to the next sound layer Using potentially-damaging paint-removal methods on wood surusing the gentlest method possible (e.g., hand scraping and hand faces, such as open-flame torches, orbital sanders, abrasive methsanding) prior to repainting. ods (including sandblasting, other media blasting, or high-pressure 

water), or caustic paint-removers. 

Removing paint that is firmly adhered to wood surfaces. 

Using chemical strippers primarily to supplement other methods Failing to neutralize the wood thoroughly after using chemical paint 

such as hand scraping, hand sanding, and thermal devices. removers so that new paint may not adhere. 

Removing paint from detachable wood features by soaking them in 

a caustic solution which can roughen the surface, split the wood, or 

result in staining from residual acid leaching out through the wood. 

Using biodegradable or environmentally-safe cleaning or paintremoval products. 

Using paint-removal methods that employ a poultice to which 

paint adheres, when possible, to neatly and safely remove old 

lead paint. 

Using a thermal device to remove paint from wood features without 

first checking for and removing any flammable debris behind them. 

Using thermal devices (such as infrared heaters) carefully to 

remove paint when it is so deteriorated that total removal is necessary prior to repainting. 

Using thermal devices without limiting the amount of time the 

wood feature is exposed to heat. 

WOOD 39
PRESERVATION

 

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND OTHER FUNCTIONAL 

AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Using coatings that encapsulate lead paint, when possible, where 

the paint is not required to be removed to meet environmental 

regulations. 

Applying compatible paint coating systems to historically-painted 

wood following proper surface preparation. 

Failing to follow manufacturers’ product and application instructions when repainting wood features. 

Repainting historically-painted wood features with colors that are 

appropriate to the building or district. 

Using paint colors on historically-painted wood features that are not 

appropriate to the building or district. 

Protecting adjacent materials when working on wood features. Failing to protect adjacent materials when working on wood features. 

Evaluating the overall condition of the wood to determine whether 

more than protection and maintenance, such as repairs to wood 

features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

wood features. 

Repairing wood by patching, splicing, consolidating, or otherwise 

reinforcing the wood using recognized preservation methods. 

Removing wood that could be stabilized, repaired, and conserved, 

or using untested consolidants, improper repair techniques, or 

unskilled personnel, potentially causing further damage to historic 

materials. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind (i.e., with wood, but not necessarily the same 

species) extensively deteriorated or missing components of wood 

features when there are surviving prototypes, such as brackets, 

molding, or sections of siding, or when the replacement can be 

based on documentary or physical evidence. The new work should 

match the old in material, design, scale, color, and finish 

Replacing an entire wood feature, such as a column or stairway, 

when limited replacement of deteriorated and missing components 

is appropriate. 

Using replacement material that does not match the historic wood 

feature. 

40 WOOD 
PRESERVATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving metal features that are Altering metal features which are important in defining the overall 

important in defining the overall historic character of the build- historic character of the building so that, as a result, the character 

ing (such as columns, capitals, pilasters, spandrel panels, or is diminished. 

stairways) and their paint, finishes, and colors. The type of metal 

should be identified prior to work because each metal has its own Replacing historic metal features instead of repairing or replacing 

properties and may require a different treatment. only the deteriorated metal. 

Changing the type of finish, coating, or historic color of metal 

features. 

Stabilizing deteriorated or damaged metal as a preliminary measure, when necessary, prior to undertaking preservation work. Failing to stabilize deteriorated or damaged metals until additional 

work is undertaken, thereby allowing further damage to occur to the 

historic building. 

Protecting and maintaining metals from corrosion by providing 

proper drainage so that water does not stand on flat, horizontal 

surfaces or accumulate in curved decorative features. 

Failing to identify and treat the causes of corrosion, such as moisture from leaking roofs or gutters. 

Placing incompatible metals together without providing an appropriate separation material. Such incompatibility can result in 

galvanic corrosion of the less noble metal (e.g., copper will corrode 

cast iron, steel, tin, and aluminum). 

Cleaning metals, when necessary, to remove corrosion prior to Failing to reapply coating systems after cleaning metals that require 

repainting or applying other appropriate protective coatings. protection from corrosion. 

Removing the patina from historic metals. The patina may be a 

protective layer on some metals (such as bronze or copper) as well 

as a distinctive finish. 

Identifying the particular type of metal prior to any cleaning Using cleaning methods which alter or damage the historic color, 

procedure and then testing to ensure that the gentlest cleaning texture, and finish of the metal, or cleaning when it is inappropriate 

method possible is selected; or, alternatively, determining that for the particular metal. 

cleaning is inappropriate for the particular metal. 

METALS 41
PRESERVATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Using non-corrosive chemical methods to clean soft metals (such 

as lead, tinplate, terneplate, copper, and zinc) whose finishes can 

be easily damaged by abrasive methods. 

Cleaning soft metals (such as lead, tinplate, terneplate, copper, and 

zinc) with abrasive methods (including sandblasting, other media 

blasting, or high-pressure water) which will damage the surface of 

the metal. 

Using the least abrasive cleaning method for hard metals (such 

as cast iron, wrought iron, and steel) to remove paint buildup and 

corrosion. If hand scraping and wire brushing have proven ineffective, low-pressure abrasive methods may be used as long as 

they do not damage the surface. 

Using high-pressure abrasive techniques (including sandblasting, 

other media blasting, or high-pressure water) without first trying 

gentler cleaning methods prior to cleaning cast iron, wrought iron, 

or steel. 

Applying appropriate paint or other coating systems to historically-coated metals after cleaning to protect them from corrosion. Applying paint or other coatings to metals (such as copper, bronze 

or stainless steel) if they were not coated historically. 

Repainting historically-painted metal features with colors that are 

appropriate to the building and district. 

Using paint colors on historically-painted metal features that are 

not appropriate to the building or district. 

Applying an appropriate protective coating (such as lacquer or 

wax) to a metal feature that was historically unpainted, such as a 

bronze door, which is subject to heavy use. 

[6] A standing-seam 

sheet metal roof, like 

the one on the turret 

of this late 19th century 

row house, must be kept 

painted to ensure its 

preservation. 

42 METALS 
PRESERVATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Protecting adjacent materials when working on metal features. Failing to protect adjacent materials when working on metal features. 

Evaluating the overall condition of metals to determine whether 

more than protection and maintenance, such as repairs to metal 

features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

metal features. 

Repairing, stabilizing, and reinforcing metal by using recognized 

preservation methods 

Removing metals that could be stabilized, repaired, and conserved, 

or using improper repair techniques, or untrained personnel, potentially causing further damage to historic materials. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing components 

of metal features when there are surviving prototypes, such as 

porch balusters, column capitals or bases, or porch cresting, or 

when the replacement can be based on documentary or physical 

evidence. The new work should match the old in material, design, 

scale, color, and finish. 

Replacing an entire metal feature, such as a column or balustrade, 

when limited replacement of deteriorated or missing components is 

appropriate. 

Using replacement material that does not match the historic metal 

feature. 

[7] (a) After the damaged 

portions of the base 

were repaired, (b) the 

cast-iron columns were 

cleaned and repainted to 

protect the metal from 

rusting. 

METALS 43
PRESERVATION

ROOFS 

RECOMMENDED NOT RECOMMENDED 

[8] Regular 

maintenance includes 

removing leaves that 

can clog gutters and 

cause water damage to 

the exterior and interior 

walls of a house. 

Identifying, retaining, and preserving roofs and their functional 

and decorative features that are important in defining the overall 

historic character of the building. The form of the roof (gable, 

hipped, gambrel, flat, or mansard) is significant, as are its decorative and functional features (such as cupolas, cresting, parapets, 

monitors, chimneys, weather vanes, dormers, ridge tiles, and snow 

guards), roofing material (such as slate, wood, clay tile, metal, roll 

roofing, or asphalt shingles), and size, color, and patterning. 

Altering the roof and roofing materials which are important in defining the overall historic character of the building so that, as a result, 

the character is diminished. 

Replacing historic roofing material instead of repairing or replacing 

only the deteriorated material. 

Changing the type or color of roofing materials. 

Stabilizing deteriorated or damaged roofs as a preliminary measure, when necessary, prior to undertaking preservation work. Failing to stabilize a deteriorated or damaged roof until additional 

work is undertaken, thereby allowing further damage to occur to the 

historic building 

Protecting and maintaining a roof by cleaning gutters and Failing to clean and maintain gutters and downspouts properly so 

downspouts and replacing deteriorated flashing. Roof sheathing that water and debris collect and cause damage to roof fasteners, 

should also be checked for indications of moisture due to leaks or sheathing, and the underlying structure 

condensation. 

Providing adequate anchorage for roofing material to guard 

against wind damage and moisture penetration. 

Allowing flashing, caps, and exposed roof fasteners to corrode, 

which accelerates deterioration of the roof. 

Protecting a leaking roof with a temporary waterproof membrane 

with a synthetic underlayment, roll roofing, plywood, or a tarpaulin until it can be repaired. 

Leaving a leaking roof unprotected so that accelerated deterioration of historic building materials (such as masonry, wood, plaster, 

paint, and structural members) occurs. 

Repainting a roofing material that requires a protective coating 

and was painted historically (such as a terneplate metal roof or 

gutters) as part of regularly-scheduled maintenance. 

Failing to repaint a roofing material that requires a protective 

coating and was painted historically as part of regularly-scheduled 

maintenance. 

Protecting a roof covering when working on other roof features. Failing to protect roof coverings when working on other roof features. 

Evaluating the overall condition of the roof to determine whether 

more than protection and maintenance, such as repairs to roof 

features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

roof features. 

Repairing a roof by ensuring that the existing historic roof or com- Removing historic materials that could be repaired or using 

patible non-historic roof covering is sound and waterproof. improper repair techniques. 

Failing to reuse intact slate or tile when only the roofing substrate 

or fasteners need replacement. 

44 ROOFS 
PRESERVATION

ROOFS 

RECOMMENDED NOT RECOMMENDED 

Using corrosion-resistant roof fasteners (e.g., nails and clips) to 

repair a roof to help extend its longevity. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing components 

of roof features when there are surviving prototypes, such as ridge 

tiles, roof cresting, or dormer trim, slates, or tiles, or when the 

replacement can be based on documentary or physical evidence. 

The new work should match the old in material, design, scale, 

color, and finish. 

Replacing an entire roof feature, such as a chimney or dormer, 

when limited replacement of deteriorated or missing components is 

appropriate. 

Using replacement material that does not match the historic roof 

feature. 

[9] Distinctively-shaped 

roofs are important in 

defining the historic 

character of these early 

20th-century structures: 

(a) an asphalt shingle 

roof on a house; (b) 

and a concrete roof on 

Fonthill, Doylestown, PA 

(1908-1912), designed 

and built by Henry 

Chapman Mercer. 

ROOFS 45
PRESERVATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving windows and their func- Altering windows or window features which are important in defintional and decorative features that are important to the overall ing the historic character of the building so that, as a result, the 

historic character of the building. The window material and how character is diminished. 

the window operates (e.g., double hung, casement, awning, or 

hopper) are significant, as are its components (including sash, Changing the appearance of windows that contribute to the historic 

muntins, ogee lugs, glazing, pane configuration, sills, mullions, character of the building by replacing materials, finishes, or colors 

casings, or brick molds) and related features, such as shutters. which noticeably change the sash, depth of reveal, and muntin configuration; the reflectivity and color of the glazing; or the appearance of the frame. 

Obscuring historic wood window trim with metal or other material. 

Stabilizing deteriorated or damaged windows as a preliminary 

measure, when necessary, prior to undertaking preservation work. 

Failing to stabilize deteriorated or damaged windows as a preliminary measure, when necessary, prior to undertaking preservation 

work. 

Protecting and maintaining the wood or metal which comprises Failing to protect and maintain materials on a cyclical basis so that 

the window jamb, sash, and trim through appropriate surface deterioration of the window results. 

treatments, such as cleaning, paint removal, and reapplication of 

the same protective coating systems. 

Protecting windows against vandalism before work begins by 

covering them and by installing alarm systems that are keyed into 

local protection agencies. 

Leaving windows unprotected and subject to vandalism before work 

begins, thereby also allowing the interior to be damaged if it can be 

accessed through unprotected windows. 

Installing impact-resistant glazing, when necessary for security, 

so that it is compatible with the historic windows and does not 

damage them or negatively impact their character. 

Installing impact-resistant glazing, when necessary for security, that 

is not compatible with the historic windows and damages them or 

negatively impacts their character. 

Making windows weathertight by recaulking gaps in fixed joints 

and replacing or installing weatherstripping. 

Replacing windows rather than maintaining the sash, frame, or 

glazing. 

Protecting windows from chemical cleaners, paint, or abrasion 

during work on the exterior of the building. 

Failing to protect historic windows from chemical cleaners, paint, 

or abrasion when work is being done on the exterior of the building. 

Protecting and retaining historic glass when replacing putty or 

repairing other components of the window. 

Failing to protect the historic glass when making repairs. 

46 WINDOWS 
PRESERVATION

[11] Old and brittle 

glazing putty should 

be removed carefully 

before reputtying to 

keep window glazing 

weathertight. 

[10] Historic exterior 

storm windows preserve 

and help to insulate 

wood windows. 

WINDOWS 47
PRESERVATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

Sustaining the historic operability of windows by lubricating friction points and replacing broken components of the operating 

system (such as hinges, latches, sash chains or cords) or replacing deteriorated gaskets or insulating units. 

Failing to maintain windows and window components so that windows are inoperable, or sealing operable sash permanently. 

Failing to repair and reuse window hardware such as sash lifts, 

latches, and locks 

Adding storm windows with a matching or a one-over-one pane 

configuration that will not obscure the characteristics of the historic windows. Storm windows improve energy efficiency and are 

especially beneficial when installed over wood windows because 

they also protect them from accelerated deterioration. 

Protecting adjacent materials when working on windows. Failing to protect adjacent materials when working on windows. 

Evaluating the overall condition of windows to determine whether 

more than protection and maintenance, such as repairs to windows and window features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

windows. 

Repairing window frames and sash by patching, splicing, consolidating, or otherwise reinforcing them using recognized preservation methods. 

Removing window frames or sash that could be stabilized, repaired, 

and conserved, or using untested consolidants, improper repair 

techniques, or untrained personnel, potentially causing furthur 

damage to historic buildings. 

Using corrosion-resistant roof fasteners (e.g., nails and clips) to 

repair a roof to help extend its longevity. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing components 

of windows when there are surviving prototypes, such as frames 

or sash, or when the replacement can be based on documentary 

or physical evidence. The new work should match the old in 

material, design, scale, color, and finish. 

Replacing an entire window when limited replacement of deteriorated or missing components is appropriate. 

Using replacement material that does not match the historic 

window. 

48 WINDOWS 
PRESERVATION

ENTRANCES AND PORCHES 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving entrances and porches and 

their functional and decorative features that are important in 

defining the overall historic character of the building. The materials themselves (including wood, masonry, and metal) are significant, as are the features, such as doors, transoms, pilasters, 

columns, balustrades, stairs, roofs, and projecting canopies. 

Altering entrances and porches which are important in defining the 

overall historic character of the building so that, as a result, the 

character is diminished. 

Replacing historic entrance and porch features instead of repairing 

or replacing only the deteriorated material. 

Stabilizing deteriorated or damaged entrances and porches as a 

preliminary measure, when necessary, prior to undertaking preservation work. 

Failing to stabilize a deteriorated or damaged entrance or porch 

until additional work is undertaken, thereby allowing further 

damage to occur to the historic building. 

[13] It is important that 

exposed swallow tail 

porch rafters be kept 

painted to protect them 

from water damage. 

[12] Repair and limited replacement in kind to 

match deteriorated wood porch features is always 

a recommended preservation treatment. 

ENTRANCES AND PORCHES 49
PRESERVATION

ENTRANCES AND PORCHES 

RECOMMENDED NOT RECOMMENDED 

Protecting and maintaining the masonry, wood, and metals which 

comprise entrances and porches through appropriate surface 

treatments, such as cleaning, paint removal, and reapplication of 

protective coating systems. 

Failing to protect and maintain historic materials on a cyclical basis 

so that deterioration of entrances and porches results. 

Protecting entrances and porches against arson and vandalism 

before work begins by covering them and by installing alarm 

systems keyed into local protection agencies. 

Leaving entrances and porches unprotected and subject to vandalism before work begins, thereby also allowing the interior to be 

damaged if it can be accessed through unprotected entrances. 

Protecting entrance and porch features when working on other 

features of the building. 

Failing to protect historic entrances and porches when working on 

other features of the building. 

Evaluating the overall condition of entrances and porches to 

determine whether more than protection and maintenance, such 

as repairs to entrance and porch features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

entrance and porch features. 

Repairing entrances and porches by patching, splicing, consolidating, or otherwise reinforcing them using recognized preservation methods. 

Removing entrances and porches or their features that could be 

stabilized, repaired, and conserved, or using untested consolidants, 

improper repair techniques, or untrained personnel, potentially 

causing further damage to historic materials. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing components of entrance and porch features when there are surviving 

prototypes, such as railings, balustrades, cornices, columns, 

sidelights, stairs, and roofs, or when the replacement can be 

based on documentary or physical evidence. The new work should 

match the old in material, design, scale, color, and finish. 

Replacing an entire entrance or porch feature when limited replacement of deteriorated and missing components is appropriate. 

Using replacement material that does not match the historic 

entrance or porch feature. 

50 ENTRANCES AND PORCHES 
PRESERVATION

STOREFRONTS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving storefronts and their func- Altering storefronts and their features which are important in defintional and decorative features that are important in defining the ing the overall historic character of the building so that, as a result, 

overall historic character of the building. The storefront materials the character is diminished. 

(including wood, masonry, metals, ceramic tile, clear glass, and 

pigmented structural glass) and the configuration of the store- Replacing historic storefront features instead of repairing or replacfront are significant, as are features, such as display windows, ing only the deteriorated material. 

base panels, bulkheads, signs, doors, transoms, kick plates, 

corner posts, piers, and entablatures. 

Stabilizing deteriorated or damaged storefronts as a preliminary 

measure, when necessary, prior to undertaking preservation work. 

Failing to stabilize a deteriorated or damaged storefront until additional work is undertaken, thereby allowing further damage to occur 

to the historic building. 

Protecting and maintaining masonry, wood, glass, ceramic tile, Failing to protect and maintain historic materials on a cyclical basis 

and metals which comprise storefronts through appropriate so that deterioration of storefront features results. 

treatments, such as cleaning, paint removal, and reapplication of 

protective coating systems. 

Protecting storefronts against arson and vandalism before work 

begins by covering windows and doors and by installing alarm 

systems keyed into local protection agencies. 

Leaving the storefront unprotected and subject to vandalism before 

work begins, thereby also allowing the interior to be damaged if it 

can be accessed through an unprotected storefront. 

Protecting the storefront when working on other features of the 

building. 

Failing to protect the storefront when working on other features of 

the building. 

[14] The signage 

is an original and 

integral part of this 

historic Carrara glass 

storefront. 

STOREFRONTS 51
PRESERVATION

STOREFRONTS 

RECOMMENDED NOT RECOMMENDED 

Evaluating the overall condition of the storefront to determine 

whether more than protection and maintenance, such as repairs 

to storefront features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

storefront features. 

Repairing storefronts by patching, splicing, consolidating, or otherwise reinforcing them using recognized preservation methods. Removing historic material that could be stabilized, repaired, and 

conserved, or using untested consolidants, improper repair techniques, or untrained personnel, potentially causing further damage 

to historic materials. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing components 

of storefronts when there are surviving prototypes, such as doors, 

transoms, kick plates, base panels, bulkheads, piers, or signs, or 

when the replacement can be based on documentary or physical 

evidence. The new work should match the old in material, design, 

scale, color, and finish. 

Replacing an entire feature or storefront when limited replacement 

of deteriorated and missing components is appropriate. 

Using replacement material that does not match the historic storefront feature. 

[15] Regular maintenance 

has helped to preserve 

this historic storefront, 

which retains all of 

its character-defining 

features, including the 

granite bulkhead, multipaned transom glazing, 

and recessed entrance. 

52 STOREFRONTS 
PRESERVATION

CURTAIN WALLS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving curtain wall systems and Altering curtain wall components which are important in defining 

their components that are important in defining the overall the overall historic character of the building so that, as a result, the 

historic character of the building. The design of the curtain character is diminished. 

wall is significant, as are its component materials (metal 

stick framing and panel materials, such as clear or spandrel Replacing historic curtain wall features instead of repairing or 

glass, stone, terra cotta, metal, and fiber-reinforced plastic), replacing only the deteriorated components. 

appearance (e.g., glazing color or tint, transparency, and 

reflectivity), and whether the glazing is fixed, operable, or 

louvered glass panels. How a curtain wall is engineered and 

fabricated, and the fact that it expands and contracts at a 

different rate from the building’s structural system, are important 

to understand when undertaking the preservation of a curtain 

wall system. 

Stabilizing deteriorated or damaged curtain walls as a preliminary measure, when necessary, prior to undertaking preservation 

work. 

Failing to stabilize deteriorated or damaged curtain walls until additional work is undertaken, thereby allowing further damage to occur 

to the historic building. 

Protecting and maintaining curtain walls and their components Failing to protect and maintain curtain wall components on a cyclithrough appropriate surface treatments, such as cleaning and cal basis so that deterioration of curtain walls results. 

reapplication of protective coating systems; and by making them 

watertight and ensuring that sealants and gaskets are in good Failing to identify and treat the various causes of curtain wall failcondition. ure, such as open gaps between components where sealants have 

deteriorated or are missing. 

Protecting ground-level curtain walls from vandalism before work 

begins by covering them, while ensuring adequate ventilation, 

and by installing alarm systems keyed into local protection agencies. 

Leaving ground-level curtain walls unprotected and subject to vandalism before work begins, thereby also allowing the interior to be 

damaged if it can be accessed through unprotected entrances. 

Installing impact-resistant glazing in a curtain wall system, when 

necessary for security or to meet code requirements, so that it is 

compatible with the historic curtain walls and does not damage 

them or negatively impact their character. 

Installing impact-resistant glazing in a curtain wall system, when 

necessary for security, that is not compatible with the historic curtain walls and damages them or negatively impacts their character. 

CURTAIN WALLS 53
PRESERVATION

CURTAIN WALLS 

RECOMMENDED NOT RECOMMENDED 

Cleaning curtain wall systems only when necessary to halt deterioration or to remove heavy soiling. Cleaning curtain wall systems when they are not heavily soiled, 

thereby needlessly introducing chemicals or moisture into historic 

materials. 

Carrying out cleaning tests, when it has been determined that 

cleaning is appropriate, using only cleaning materials that will 

not damage components of the system, including factory-applied 

finishes. Test areas should be examined to ensure that no 

damage has resulted. 

Cleaning curtain wall systems without testing first or using cleaning 

materials that may damage components of the system. 

Evaluating the overall condition of curtain walls to determine 

whether more than protection and maintenance, such as repairs 

to curtain wall components, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

curtain wall components. 

Repairing curtain walls by ensuring that they are watertight by Removing curtain wall components that could be stabilized, 

augmenting existing components or replacing deteriorated or repaired, and conserved, or using improper repair techniques, or 

missing sealants or gaskets, where necessary, to seal any gaps untrained personnel, potentially causing further damage to historic 

between system components. materials. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing compo- Replacing an entire curtain wall feature when limited replacement 

nents of a curtain wall system when there are surviving proto­ of deteriorated and missing components is appropriate. 

types or when the replacement can be based on documentary or 

physical evidence. The new work should match the old in mate- Using replacement material that does not match the historic curtain 

rial, design, scale, color, and finish. wall feature. 

[16] Plywood provides 

temporary protection 

for an opening where a 

damaged spandrel panel 

was removed until a 

matching replacement 

panel can be installed. 

54 CURTAIN WALLS 
PRESERVATION

STRUCTURAL SYSTEMS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving structural systems and visible features of systems that are important in defining the overall 

historic character of the building. This includes the materials that 

comprise the structural system (i.e., wood, metal, and masonry), 

the type of system, and its features, such as posts and beams, 

trusses, summer beams, vigas, cast-iron or masonry columns, 

above-grade stone foundation walls, or load-bearing masonry 

walls. 

Altering visible features of historic structural systems which are 

important in defining the overall historic character of the building 

so that, as a result, the character is diminished. 

Overloading the existing structural system, or installing equipment 

or mechanical systems which could damage the structure. 

Replacing a load-bearing masonry wall that could be augmented 

and retained. 

Leaving known structural problems untreated, such as deflected 

beams, cracked and bowed walls, or racked structural members. 

Stabilizing deteriorated or damaged structural systems as a pre- Failing to stabilize a deteriorated or damaged structural system 

liminary measure, when necessary, prior to undertaking preserva­ until additional work is undertaken, thereby allowing further 

tion work. damage to occur to the historic building. 

Failing to protect and maintain the structural system on a cyclical 

basis so that deterioration of the structural system results. 

Protecting and maintaining the structural system by keeping 

gutters and downspouts clear and roofing in good repair; and 

by ensuring that wood structural members are free from insect 

infestation. 

Using treatments or products that may retain moisture, which 

accelerates deterioration of structural members. 

STRUCTURAL SYSTEMS 55
PRESERVATION

56

[17] Distinctive examples of traditional construction 

techniques should be preserved, such as this wooden 

peg, which is part of the structural system of this 

late-19th-century warehouse. 

[18] A massive, exposed, concrete structural system 

defines the historic character of the interior of St. 

John’s Abbey, Collegeville, MN, designed by Marcel 

Breuer and constructed in 1961. 

STRUCTURAL SYSTEMS 
PRESERVATION

STRUCTURAL SYSTEMS 

RECOMMENDED NOT RECOMMENDED 

Evaluating the overall condition of the structural system to determine whether more than protection and maintenance, such as 

repairs to structural features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

structural systems. 

Repairing the structural system by augmenting individual com- Upgrading the building structurally in a manner that diminishes 

ponents, using recognized preservation methods. For example, the historic character of the exterior (such as installing strapping 

weakened structural members (such as floor framing) can be channels or removing a decorative cornice) or that damages interior 

paired or sistered with a new member, braced, or otherwise features or spaces. 

supplemented and reinforced. 

Replacing a structural member or other feature of the structural 

system when it could be augmented and retained. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind those visible portions or features of the structural system that are either extensively deteriorated or missing 

when there are surviving prototypes, such as cast-iron columns 

and sections of load-bearing walls, or when the replacement can 

be based on documentary or physical evidence. The new work 

should match the old in material, design, scale, color, and finish. 

Replacing an entire curtain wall feature when limited replacement 

of deteriorated and missing components is appropriate. 

Using replacement material that does not match the historic curtain 

wall feature. 

Considering the use of substitute material to replace structural Using substitute material that does not equal the load-bearing 

features that are not visible. Substitute material must be struc­ capabilities of the historic material or is physically incompatible 

turally sufficient and physically compatible with the rest of the with the structural system. 

system. 

STRUCTURAL SYSTEMS 57
PRESERVATION

MECHANICAL SYSTEMS: 

HEATING, AIR CONDITIONING, ELECTRICAL, AND PLUMBING 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving visible features of early 

mechanical systems that are important in defining the overall 

historic character of the building, such as radiators, vents, fans, 

grilles, and plumbing and lighting fixtures. 

Removing or altering visible features of mechanical systems that are 

important in defining the overall historic character of the building 

so that, as a result, the character is diminished. 

Stabilizing functioning mechanical systems as a preliminary measure, when necessary, prior to undertaking preservation work. Failing to stabilize a functioning mechanical system and its visible 

features until additional work is undertaken. 

Protecting and maintaining functioning mechanical, plumbing, 

and electrical systems and their features through cyclical maintenance. 

Failing to protect and maintain functioning mechanical, plumbing, 

and electrical systems on a cyclical basis so that their deterioration 

results. 

Improving the energy efficiency of existing mechanical systems 

to help reduce the need for a new system by installing storm 

windows, insulating attics and crawl spaces, or adding awnings, 

if appropriate. 

Evaluating the overall condition of functioning mechanical 

systems to determine whether more than protection and maintenance, such as repairs to mechanical system components, will be 

necessary. 

Failing to undertake adequate measures to ensure the protection of 

structural systems. 

Repairing mechanical systems by augmenting or upgrading 

system components (such as installing new pipes and ducts), 

rewiring, or adding new compressors or boilers. 

Replacing a mechanical system when its components could be 

upgraded and retained. 

58 MECHANICAL SYSTEMS 
PRESERVATION

MECHANICAL SYSTEMS: 

HEATING, AIR CONDITIONING, ELECTRICAL, AND PLUMBING 

RECOMMENDED NOT RECOMMENDED 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind those extensively deteriorated or missing visible 

features of mechanical systems when there are surviving prototypes, such as ceiling fans, radiators, grilles, or lighting fixtures. 

Installing a visible replacement feature that does not convey the 

same appearance. 

The following work should be considered in a Preservation project when the installation of new mechanical equipment or an entire system is required to 

make the building functional. 

Installing a new mechanical system, if required, so that it results 

in the least alteration possible to the historic building and its 

character-defining features. 

Installing a new mechanical system so that character-defining 

structural or interior features are radically changed, damaged, or 

destroyed. 

Providing adequate structural support for new mechanical equipment. Failing to consider the weight and design of new mechanical equipment so that, as a result, historic structural members or finished 

surfaces are weakened or cracked. 

Installing new mechanical and electrical systems and ducts, 

pipes, and cables in closets, service areas, and wall cavities to 

preserve the historic character of the interior space. 

Installing ducts, pipes, and cables where they will obscure character-defining features or negatively impact the historic character of 

the interior. 

Concealing mechanical equipment in walls or ceilings in a manner 

that results in extensive loss or damage or otherwise obscures historic building materials and character-defining features. 

MECHANICAL SYSTEMS 59
PRESERVATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving a floor plan or interior 

spaces, features, and finishes that are important in defining 

the overall historic character of the building. Significant spatial 

characteristics include the size, configuration, proportion, and 

relationship of rooms and corridors; the relationship of features to 

spaces; and the spaces themselves, such as lobbies, lodge halls, 

entrance halls, parlors, theaters, auditoriums, gymnasiums, and 

industrial and commercial interiors. Color, texture, and pattern 

are important characteristics of features and finishes, which can 

include such elements as columns, plaster walls and ceilings, 

flooring, trim, fireplaces and mantels, paneling, light fixtures, 

hardware, decorative radiators, ornamental grilles and registers, 

windows, doors, and transoms; plaster, paint, wallpaper and wall 

coverings, and special finishes, such as marbleizing and graining; 

and utilitarian (painted or unpainted) features, including wood, 

metal, or concrete exposed columns, beams, and trusses and 

exposed load-bearing brick, concrete, and wood walls. 

Altering a floor plan, interior spaces (including individual rooms), 

features, or finishes which are important in defining the overall 

historic character of the building so that, as a result, the character 

is diminished. 

Replacing historic interior features and finishes instead of repairing 

or replacing only the deteriorated portion. 

Installing new material that obscures or damages character-defining 

interior features and finishes. 

Removing paint, plaster, or other finishes from historically-finished 

interior surfaces and leaving the features exposed (e.g., removing 

plaster to expose brick walls or a brick chimney breast, stripping 

paint from wood to stain or varnish it, or removing a plaster ceiling 

to expose unfinished beams). 

Applying paint, plaster, or other coatings to surfaces that have been 

unfinished historically, thereby changing their character. 

Changing the type of finish or its color, such as painting a historically-varnished wood feature, or removing paint from a historicallypainted feature. 

Stabilizing deteriorated or damaged interior features and finishes 

as a preliminary measure, when necessary, prior to undertaking 

preservation work. 

Failing to stabilize a deteriorated or damaged interior feature or 

finish until additional work can be undertaken, thereby allowing 

further damage to occur to the interior. 

Protecting and maintaining historic materials (including plaster, 

masonry, wood, and metals) which comprise interior features 

through appropriate surface treatments, such as cleaning, paint 

removal, and reapplication of protective coating systems. 

Failing to protect and maintain interior materials and finishes on a 

cyclical basis so that deterioration of interior features results. 

60 INTERIOR SPACES, FEATURES, AND FINISHES 
PRESERVATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Protecting interior features and finishes against arson and vandalism before project work begins by erecting temporary fencing or 

by covering broken windows and open doorways, while ensuring 

adequate ventilation, and by installing alarm systems keyed into 

local protection agencies. 

Leaving the building unprotected and subject to vandalism before 

work begins, thereby allowing the interior to be damaged if it can be 

accessed through unprotected openings. 

Protecting interior features (such as a staircase, mantel, flooring, 

or decorative finishes) from damage during project work by covering them with plywood, heavy canvas, or plastic sheeting. 

Failing to protect interior features and finishes when working on the 

interior. 

[19] The sweeping 

staircase with its metal 

railing, chandelier, and 

terrazzo floor in the 

lobby of the 1954 Simms 

Building, Albuquerque, 

NM, are characterdefining features. Photo: 

Harvey M. Kaplan. 

[20] It is important 

to protect decorative 

interior features, such 

as this highly-glazed 

tile wainscoting in a 

historic train station, 

when painting the walls 

above it. 

INTERIOR SPACES, FEATURES, AND FINISHES 61
PRESERVATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Removing damaged or deteriorated paint and finishes only to Removing paint that is firmly adhered to interior materials and 

the next sound layer using the gentlest method possible prior to features. 

repainting or refinishing using compatible paint or other coating 

systems. 

Using abrasive cleaning methods only on the interior of industrial 

or warehouse buildings with utilitarian, unplastered masonry 

walls and where wood features are not finished, molded, beaded, 

or worked by hand. Low-pressure abrasive cleaning (e.g., sandblasting or other media blasting) should only be considered if test 

patches show no surface damage and after gentler methods have 

proven ineffective. 

Using abrasive methods anywhere but utilitarian and industrial 

interior spaces or when there are other cleaning methods that are 

less likely to damage the surface of the material. 

Evaluating the overall condition of the interior materials, features, Failing to undertake adequate measures to ensure the protection of 

and finishes to determine whether more than protection and interior materials, features, and finishes. 

maintenance, such as repairs to features and finishes, will be 

necessary. 

Repairing interior features and finishes by patching, splicing, Removing interior features or finishes that could be stabilized, 

consolidating, or otherwise reinforcing the materials using recog­ repaired, and conserved, or using untested consolidants, improper 

nized preservation methods. repair techniques, or untrained personnel, potentially causing further damage to historic materials. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing components Replacing an entire interior feature when limited replacement of 

of interior features when there are surviving prototypes (such deteriorated and missing components is appropriate. 

as stairs, balustrades, wood paneling, columns, decorative wall 

finishes, and ornamental plaster or pressed-metal ceilings); or Using replacement material that does not match the historic interior 

when the replacement can be based on documentary or physical feature or finish. 

evidence. The new work should match the old in material, design, 

scale, color, and finish. 

62 INTERIOR SPACES, FEATURES, AND FINISHES 
PRESERVATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving features of the building site 

that are important in defining its overall historic character. Site 

features may include walls, fences, or steps; circulation systems, 

such as walks, paths, or roads; vegetation, such as trees, shrubs, 

grass, orchards, hedges, windbreaks, or gardens; landforms, such 

as hills, terracing, or berms; furnishings and fixtures, such as 

light posts or benches; decorative elements, such as sculpture, 

statuary, or monuments; water features, including fountains, 

streams, pools, lakes, or irrigation ditches; and subsurface 

archeological resources, other cultural or religious features, or 

burial grounds which are also important to the site. 

Altering buildings and their features or site features which are 

important in defining the overall historic character of the property 

so that, as a result, the character is diminished. 

Retaining the historic relationship between buildings and the 

landscape. 

Removing or relocating buildings or landscape features, thereby 

destroying the historic relationship between buildings and the 

landscape. 

[21] (a) The formal 

garden on the property 

of the 1826 BeauregardKeyes House in New 

Orleans (b) is integral to 

the character of the site. 

BUILDING SITE 63
PRESERVATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Stabilizing deteriorated or damaged building and site features 

as a preliminary measure, when necessary, prior to undertaking 

preservation work. 

Failing to stabilize a deteriorated or damaged building or site 

feature until additional work can be undertaken, thereby allowing 

further damage to occur to the building site. 

Protecting and maintaining buildings and site features by providing proper drainage to ensure that water does not erode foundation walls, drain toward the building, or damage or erode the 

landscape. 

Failing to ensure that site drainage is adequate so that buildings 

and site features are damaged or destroyed; or, alternatively, changing the site grading so that water does not drain properly. 

Minimizing disturbance of the terrain around buildings or Using heavy machinery or equipment in areas where it may disturb 

elsewhere on the site, thereby reducing the possibility of destroy- or damage important landscape features, archeological resources, 

ing or damaging important landscape features, archeological other cultural or religious features, or burial grounds. 

resources, other cultural or religious features, or burial grounds. 

Protecting (e.g., preserving in place) important site features, 

archeological resources, other cultural or religious features, or 

burial grounds. 

Leaving known site features or archeological material unprotected 

so that it is damaged during preservation work. 

Planning and carrying out any necessary investigation before 

preservation begins, using professional archeologists and methods when preservation in place is not feasible. 

Allowing unqualified personnel to perform data recovery on archeological resources, which can result in damage or loss of important 

archeological material. 

Preserving important landscape features through regularly-scheduled maintenance of historic plant material. Allowing important landscape features or archeological resources to 

be lost, damaged, or to deteriorate due to inadequate protection or 

lack of maintenance. 

Protecting the building site and landscape features against arson Leaving the property unprotected and subject to vandalism before 

and vandalism before preservation work begins by erecting tem­ work begins so that the building site and landscape features, 

porary fencing and by installing alarm systems keyed into local archeological resources, other cultural or religious features, or burial 

protection agencies. grounds can be damaged or destroyed. 

Installing protective fencing, bollards, and stanchions on a build- Installing protective fencing, bollards, and stanchions on a building 

ing site, when necessary for security, that are as unobtrusive as site, when necessary for security, without taking into consideration 

possible. their location and visibility so that they negatively impact the historic character of the site. 

Providing continued protection and maintenance of buildings and 

landscape features on the site through appropriate grounds or 

landscape management. 

Removing or destroying features from the site, such as fencing, 

paths or walkways, masonry balustrades, or plant material. 

64 BUILDING SITE 
PRESERVATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Protecting building and landscape features when working on the 

site. 

Failing to protect building and landscape features during work on 

the site. 

Evaluating the overall condition of the site to determine whether 

more than protection and maintenance, such as repairs to materials and features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

the site. 

Repairing building and site features which have damaged, deteriorated, or missing components to reestablish the whole feature 

and to ensure retention of the integrity of historic materials. 

Failing to repair damaged or deteriorated site features. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing features of 

the site when there are surviving prototypes, such as part of a 

fountain, portions of a walkway, or a hedge, or when the replacement can be based on documentary or physical evidence. The 

new work should match the old in material, design, scale, and 

color. 

Replacing an entire feature of the building or site when limited 

replacement of deteriorated or missing components is appropriate. 

Using replacement material that does not match the historic site 

feature. 

[22 a-b] The 1907 

Commander General’s 

Quarters facing 

Continental Park 

is one of many 

important structures 

that contribute to the 

historic significance and 

character of Fort Monroe, 

a National Monument, in 

Hampton, VA. 

BUILDING SITE 65
PRESERVATION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving building and landscape fea- Altering those building and landscape features of the setting which 

tures that are important in defining the overall historic character are important in defining its historic character so that, as a result, 

of the setting. Such features can include circulation systems, the character is diminished. 

such as roads and streets; furnishings and fixtures, such as light 

posts or benches; vegetation, gardens, and yards; adjacent open 

space, such as fields, parks, commons, or woodlands; and important views or visual relationships. 

Retaining the historic relationship between buildings and 

landscape features in the setting. For example, preserving the 

relationship between a town common or urban plaza and the 

adjacent houses, municipal buildings, roads, and landscape and 

streetscape features. 

Altering the relationship between the buildings and landscape features in the setting by widening existing streets, changing landscape 

materials, or locating new streets or parking areas where they may 

negatively impact the historic character of the setting. 

Removing or relocating historic buildings or landscape features, 

thereby destroying the historic relationship between buildings and 

the landscape in the setting. 

[23] The city square is 

important in defining 

the character of the 

historic setting in this 

small town. 

66 SETTING (DISTRICT/NEIGHBORHOOD) 
PRESERVATION

[24] Cast-iron porches 

and wrought-iron 

fences from the late 19th 

century typify this block 

in an urban historic 

district. 

[25] Street names in tile 

set into the sidewalk are 

distinctive features in 

this historic district. 

SETTING (DISTRICT/NEIGHBORHOOD) 67
PRESERVATION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

Stabilizing deteriorated or damaged building or landscape features in the setting as a preliminary measure, when necessary, 

prior to undertaking preservation work. 

Failing to stabilize a deteriorated or damaged building or landscape 

feature in the setting until additional work can be undertaken, 

thereby allowing further damage to occur to the setting. 

Protecting and maintaining historic features in the setting Failing to protect and maintain materials in the setting on a cyclithrough regularly-scheduled maintenance and landscape man- cal basis so that deterioration of building and landscape features 

agement. results. 

Stripping or removing historic features from buildings or the setting, 

such as a porch, fencing, walkways, or plant material. 

Installing protective fencing, bollards, and stanchions in the Installing protective fencing, bollards, and stanchions in the setting, 

setting, when necessary for security, that are as unobtrusive as when necessary for security, without taking into consideration their 

possible. location and visibility so that they negatively impact the historic 

character of the setting. 

Protecting building and landscape features when undertaking 

work in the setting. 

Failing to protect building and landscape features during work in 

the setting. 

Evaluating the overall condition of materials and features to Failing to undertake adequate measures to ensure the protection of 

determine whether more than protection and maintenance, such materials and features of the setting. 

as repairs to materials and features in the setting, will be necessary. 

Repairing features in the setting by reinforcing the historic materials, using recognized preservation methods. 

Removing material that could be repaired or using improper repair 

techniques. 

The following work is highlighted to indicate that it represents the greatest degree of intervention generally recommended within the treatment 

Preservation, and should only be considered after protection, stabilization, and repair concerns have been addressed. 

Limited Replacement in Kind 

Replacing in kind extensively deteriorated or missing compo- Replacing an entire feature of the building or landscape when limnents of building and landscape features in the setting when ited replacement of deteriorated or missing components is approprithere are surviving prototypes, such as balustrades or paving ate. 

materials, or when the replacement can be based on documentary or physical evidence. The new work should match the old in Using replacement material that does not match the historic buildmaterial, design, scale, and color. ing or landscape feature. 

68 SETTING (DISTRICT/NEIGHBORHOOD) 
PRESERVATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Sensitive solutions to meeting code requirements are an important part of protecting the historic character of the building and site. Thus, work that must be 

done to meet accessibility and life-safety requirements in the treatment Preservation must also be assessed for its potential impact on the historic building 

and site. 

ACCESSIBILITY 

Identifying the historic building’s character-defining exterior Undertaking accessibility code-required alterations before identifyfeatures, interior spaces, features, and finishes, and features of ing those exterior features, interior spaces, features, and finishes, 

the site and setting which may be affected by accessibility code- and features of the site and setting which are character defining 

required work. and, therefore, must be preserved. 

Complying with barrier-free access requirements in such a Altering, damaging, or destroying character-defining exterior feamanner that the historic building’s character-defining exterior fea­ tures, interior spaces, features, and finishes, or features of the site 

tures, interior spaces, features, and finishes, and features of the and setting while making modifications to a building, its site, or 

site and setting are preserved or impacted as little as possible. setting to comply with accessibility requirements. 

Working with specialists in accessibility and historic preservation Making changes to historic buildings, their sites, and setting 

to determine the most sensitive solutions to comply with access without first consulting with specialists in accessibility and historic 

requirements in a historic building, its site, and setting. preservation to determine the most appropriate solutions to comply 

with accessibility requirements. 

Providing barrier-free access that promotes independence for the 

user while preserving significant historic features. 

Making access modifications that do not provide independent, safe 

access or preserve historic features. 

Finding solutions to meet accessibility requirements that minimize the impact of any necessary alteration for accessibility 

on the historic building, its site, or setting, such as compatible 

ramps, paths, and lifts. 

Making modifications for accessibility without considering the 

impact on the historic building, its site, and setting. 

CODE-REQUIRED WORK | ACCESSIBILITY 69
PRESERVATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Using relevant sections of existing codes regarding accessibility 

for historic buildings that provide alternative means of compliance when code-required work would otherwise negatively impact 

the historic character of the property. 

Minimizing the visual impact of accessibility ramps by installing them on secondary elevations when it does not compromise 

accessibility or by screening them with plantings. 

Adding a gradual slope or grade to the sidewalk, if appropriate, 

to access the entrance rather than installing a ramp that would 

be more intrusive to the historic character of the building and the 

district. 

Installing a lift as inconspicuously as possible when it is necessary to locate it on a primary elevation of the historic building. Installing a lift at a primary entrance without considering other 

options or locations. 

[26] A temporary ramp— 

unobtrusive and easily 

removed—facilitates 

access to the entrance 

of this museum and does 

not affect its historic 

character. 

[27] The access ramp at 

the left of the entrance 

is concealed by a hedge 

which minimizes its 

visibility and impact 

on the character of 

the historic apartment 

building. 

70 CODE-REQUIRED WORK | ACCESSIBILITY 
PRESERVATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

LIFE SAFETY 

Identifying the historic building’s character-defining exterior Undertaking life-safety code-required alterations before identifying 

features, interior spaces, features, and finishes, and features of those exterior features, interior spaces, features, and finishes, and 

the site and setting which may be affected by life-safety code- features of the site and setting which are character defining and, 

required work. therefore, must be preserved. 

Complying with life-safety codes (including requirements for Altering, damaging, or destroying character-defining exterior feaimpact-resistant glazing, security, and seismic retrofit) in such a tures, interior spaces, features, and finishes, or features of the site 

manner that the historic building’s character-defining exterior fea­ and setting while making modifications to a building, its site, or 

tures, interior spaces, features, and finishes, and features of the setting to comply with life-safety code requirements. 

site and setting are preserved or impacted as little as possible. 

Removing building materials only after testing has been conducted to identify any hazardous materials, and using only the 

least damaging abatement methods. 

Removing building materials without testing first to identify any 

hazardous materials, or using potentially damaging methods of 

abatement. 

Providing workers with appropriate personal equipment for protection from hazards on the worksite. Removing hazardous or toxic materials without regard for workers’ health and safety or environmentally-sensitive disposal of the 

materials. 

Working with code officials and historic preservation specialists Making life-safety code-required changes to the building without 

to investigate systems, methods, or devices to make the build- consulting code officials and historic preservation specialists, with 

ing compliant with life-safety codes to ensure that necessary the result that alterations negatively impact the historic character of 

alterations will be compatible with the historic character of the the building. 

building. 

Using relevant sections of existing codes regarding life safety for 

historic buildings that provide alternative means of code compliance when code-required work would otherwise negatively impact 

the historic character of the building. 

Upgrading historic stairways and elevators to meet life-safety 

codes so that they are not damaged or otherwise negatively 

impacted. 

Damaging or making inappropriate alterations to historic stairways 

and elevators or to adjacent spaces, features, or finishes in the 

process of doing work to meet code requirements. 

Installing sensitively-designed fire-suppression systems, such as 

sprinklers, so that historic features and finishes are preserved. 

Covering character-defining wood features with fire-retardant 

sheathing, which results in altering their appearance. 

Applying fire-retardant coatings when appropriate, such as intumescent paint, to protect steel structural systems. Using fire-retardant coatings if they will damage or obscure character-defining features. 

[28] A simple railing 

added on the inner side 

of an elaborate wood 

and cast-iron stair railing 

meets life-safety code 

requirements without 

greatly impacting its 

historic character. 

[29] A safety cone 

outside of a house 

where lead paint is being 

removed warns of the 

hazardous conditions on 

the site. 

CODE-REQUIRED WORK | LIFE SAFETY 71
PRESERVATION

RESILIENCE TO NATURAL HAZARDS 

RECOMMENDED NOT RECOMMENDED 

Resilience to natural hazards should be addressed as part of a Preservation project. A historic building may have existing characteristics or features that 

help to address or minimize the impacts of natural hazards. These should always be used to best advantage when considering new adaptive treatments so as 

to have the least impact on the historic character of the building, its site, and setting. 

Identifying the vulnerabilities of the historic property to the Failing to identify and periodically reevaluate the potential vulnerimpacts of natural hazards (such as wildfires, hurricanes, or ability of the building, its site, and setting to the impacts of natural 

tornadoes) using the most current climate information and data hazards. 

available. 

Assessing the potential impacts of known vulnerabilities on 

character-defining features of the building, its site, and setting, 

and reevaluating and reassessing potential impacts on a regular 

basis. 

Documenting the property and its character-defining features as 

a record and guide for future repair work, should it be necessary, 

and storing the documentation in a weatherproof location. 

Failing to document the historic property and its character-defining 

features with the result that such information is not available in the 

future to guide repair or reconstruction work, should it be necessary. 

Ensuring that historic resource inventories and maps are accurate, up to date, and accessible in an emergency. 

Maintaining the building, its site, and setting in good repair, and 

regularly monitoring character-defining features. 

Failing to regularly monitor and maintain the property and building 

systems in good repair. 

Using and maintaining existing characteristics and features of the 

historic building, its site, setting, and larger environment (such 

as shutters for storm protection or a site wall that keeps out flood 

waters) that may help to avoid or minimize the impacts of natural 

hazards. 

Undertaking work to prevent or minimize the loss, damage, or Allowing loss, damage, or destruction to occur to the historic builddestruction of the historic property while retaining and preserving ing, its site, or setting by failing to evaluate potential future impacts 

significant features and the overall historic character of the build- of natural hazards or to plan and implement adaptive measures, if 

ing, its site, and setting. necessary to address possible threats. 

Ensuring that, when planning work to adapt for natural hazards, 

all feasible alternatives are considered, and that options requiring 

the least alteration are considered first. 

72 RESILIENCE TO NATURAL HAZARDS 
PRESERVATION

RESILIENCE TO NATURAL HAZARDS 

RECOMMENDED NOT RECOMMENDED 

Implementing local and regional traditions (such as elevating 

residential buildings at risk of flooding or reducing flammable 

vegetation around structures in fire-prone areas) for adapting 

buildings and sites to specific natural hazards, when appropriate. 

Such traditional methods may be appropriate if they are compatible with the historic character of the building, its site, and 

setting. 

Implementing a treatment traditionally used in another region or 

one typically used for a different property type or architectural style 

which is not compatible with the historic character of the property. 

Using special exemptions and variances when adaptive treatments to protect buildings from known hazards would otherwise 

negatively impact the historic character of the building, its site, 

or setting. 

Considering adaptive options, whenever possible, that would 

protect multiple historic resources, if the treatment can be implemented without negatively impacting the historic character of the 

setting or district, or archeological resources, other cultural or 

religious features, or burial grounds. 

[30] Historic window 

shutters still serve their 

original function as 

protection in hurricaneprone areas. 

RESILIENCE TO NATURAL HAZARDS 73
PRESERVATION

74

Sustainability 

Sustainability should be addressed as part of a Preservation project. 

Good preservation practice is often synonymous with sustainability. 

Existing energy-efficient features should be retained and repaired. 

New sustainability treatments generally should be limited to 

updating existing features and systems to have the least impact on 

the historic character of the building. 

The topic of sustainability is addressed in detail in The Secretary of 

the Interior’s Standards for Rehabilitation & Illustrated Guidelines 

on Sustainability for Rehabilitating Historic Buildings. Although 

specifically developed for the treatment Rehabilitation, the 

Sustainability Guidelines can be used to help guide the other 

treatments. 

[31] An interior screen 

door at the entrance to 

individual apartments 

is a historic feature 

traditionally used to help 

circulate air throughout 

the building. 

SUSTAINIBILITY 
REHABILITATION REHABILITATION

STANDARDS FOR REHABILITATION & GUIDELINES 

FOR REHABILITATING HISTORIC BUILDINGS 

Rehabilitation
 

Rehabilitation is defined as the act or process of making possible a 

compatible use for a property through repair, alterations, and additions 

while preserving those portions or features which convey its historical, 

cultural, or architectural values. 

75
REHABILITATION

76

Standards for Rehabilitation 

1.	 A property will be used as it was historically or be given a new use that requires minimal 

change to its distinctive materials, features, spaces and spatial relationships. 

2.	 The historic character of a property will be retained and preserved. The removal of distinctive materials or alteration of features, spaces and spatial relationships that characterize a property will be avoided. 

3.	 Each property will be recognized as a physical record of its time, place and use. Changes 

that create a false sense of historical development, such as adding conjectural features or 

elements from other historic properties, will not be undertaken. 

4.	 Changes to a property that have acquired historic significance in their own right will be 

retained and preserved. 

5.	 Distinctive materials, features, finishes, and construction techniques or examples of 

craftsmanship that characterize a property will be preserved. 

6.	 Deteriorated historic features will be repaired rather than replaced. Where the severity 

of deterioration requires replacement of a distinctive feature, the new feature will match 

the old in design, color, texture and, where possible, materials. Replacement of missing 

features will be substantiated by documentary and physical evidence. 

7.	 Chemical or physical treatments, if appropriate, will be undertaken using the gentlest 

means possible. Treatments that cause damage to historic materials will not be used. 

8.	 Archeological resources will be protected and preserved in place. If such resources must 

be disturbed, mitigation measures will be undertaken. 

9.	 New additions, exterior alterations, or related new construction will not destroy historic 

materials, features, and spatial relationships that characterize the property. The new work 

will be differentiated from the old and will be compatible with the historic materials, features, size, scale and proportion, and massing to protect the integrity of the property and 

its environment. 

10. New additions and adjacent or related new construction will be undertaken in such a 

manner that, if removed in the future, the essential form and integrity of the historic 

property and its environment would be unimpaired. 
REHABILITATION

GUIDELINES FOR REHABILITATING HISTORIC BUILDINGS
 

INTRODUCTION 

In Rehabilitation, historic building materials and character-defining 

features are protected and maintained as they are in the treatment 

Preservation. However, greater latitude is given in the Standards 

for Rehabilitation and Guidelines for Rehabilitating Historic 

Buildings to replace extensively deteriorated, damaged, or missing features using either the same material or compatible substitute materials. Of the four treatments, only Rehabilitation allows 

alterations and the construction of a new addition, if necessary for a 

continuing or new use for the historic building. 

Identify, Retain, and Preserve Historic 

Materials and Features 

The guidance for the treatment Rehabilitation begins with recommendations to identify the form and detailing of those architectural 

materials and features that are important in defining the building’s 

historic character and which must be retained to preserve that character. Therefore, guidance on identifying, retaining, and preserving 

character-defining features is always given first. 

Protect and Maintain Historic Materials and 

Features 

After identifying those materials and features that are important 

and must be retained in the process of Rehabilitation work, then 

protecting and maintaining them are addressed. Protection generally 

involves the least degree of intervention and is preparatory to other 

work. Protection includes the maintenance of historic materials and 

features as well as ensuring that the property is protected before and 

during rehabilitation work. A historic building undergoing rehabilitation will often require more extensive work. Thus, an overall evaluation of its physical condition should always begin at this level. 

Repair Historic Materials and Features 

Next, when the physical condition of character-defining materials 

and features warrants additional work, repairing is recommended. 

Rehabilitation guidance for the repair of historic materials, such as 

masonry, again begins with the least degree of intervention possible. 

In rehabilitation, repairing also includes the limited replacement in 

kind or with a compatible substitute material of extensively deteriorated or missing components of features when there are surviving prototypes features that can be substantiated by documentary 

and physical evidence. Although using the same kind of material is 

always the preferred option, a substitute material may be an acceptable alternative if the form, design, and scale, as well as the substitute material itself, can effectively replicate the appearance of the 

remaining features. 

Replace Deteriorated Historic Materials and 

Features 

Following repair in the hierarchy, Rehabilitation guidance is provided for replacing an entire character-defining feature with new 

material because the level of deterioration or damage of materials 

precludes repair. If the missing feature is character defining or if it 

is critical to the survival of the building (e.g., a roof), it should be 

replaced to match the historic feature based on physical or hisINTRODUCTION 77
REHABILITATION

78

toric documentation of its form and detailing. As with repair, the 

preferred option is always replacement of the entire feature in kind 

(i.e., with the same material, such as wood for wood). However, 

when this is not feasible, a compatible substitute material that can 

reproduce the overall appearance of the historic material may be 

considered. 

It should be noted that, while the National Park Service guidelines 

recommend the replacement of an entire character-defining feature 

that is extensively deteriorated, the guidelines never recommend 

removal and replacement with new material of a feature that could 

reasonably be repaired and, thus, preserved. 

Design for the Replacement of Missing 

Historic Features 

When an entire interior or exterior feature is missing, such as a 

porch, it no longer plays a role in physically defining the historic 

character of the building unless it can be accurately recovered in 

form and detailing through the process of carefully documenting 

the historic appearance. If the feature is not critical to the survival 

of the building, allowing the building to remain without the feature 

is one option. But if the missing feature is important to the historic 

character of the building, its replacement is always recommended 

in the Rehabilitation guidelines as the first, or preferred, course 

of action. If adequate documentary and physical evidence exists, 

the feature may be accurately reproduced. A second option in a 

rehabilitation treatment for replacing a missing feature, particularly 

when the available information about the feature is inadequate to 

permit an accurate reconstruction, is to design a new feature that 

is compatible with the overall historic character of the building. 

The new design should always take into account the size, scale, and 

material of the building itself and should be clearly differentiated 

from the authentic historic features. For properties that have 

changed over time, and where those changes have acquired 

significance, reestablishing missing historic features generally 

should not be undertaken if the missing features did not coexist 

with the features currently on the building. Juxtaposing historic 

features that did not exist concurrently will result in a false sense of 

the building’s history. 

Alterations 

Some exterior and interior alterations to a historic building are 

generally needed as part of a Rehabilitation project to ensure its 

continued use, but it is most important that such alterations do 

not radically change, obscure, or destroy character-defining spaces, 

materials, features, or finishes. Alterations may include changes 

to the site or setting, such as the selective removal of buildings or 

other features of the building site or setting that are intrusive, not 

character defining, or outside the building’s period of significance. 

Code-Required Work: 

Accessibility and Life Safety 

Sensitive solutions to meeting code requirements in a 

Rehabilitation project are an important part of protecting the 

historic character of the building. Work that must be done to meet 

accessibility and life-safety requirements must also be assessed for 

its potential impact on the historic building, its site, and setting. 

Resilience to Natural Hazards 

Resilience to natural hazards should be addressed as part of a 

Rehabilitation project. A historic building may have existing 

characteristics or features that help to address or minimize the 

impacts of natural hazards. These should always be used to best 

advantage when considering new adaptive treatments so as to have 

the least impact on the historic character of the building, its site, 

and setting. 

INTRODUCTION 
REHABILITATION

 

 

Sustainability 

Sustainability should be addressed as part of a Rehabilitation proj­

ect. Good preservation practice is often synonymous with sustain­

ability. Existing energy-efficient features should be retained and 

repaired. Only sustainability treatments should be considered that 

will have the least impact on the historic character of the building. 

The topic of sustainability is addressed in detail in The Secretary 

of the Interior’s Standards for Rehabilitation & Illustrated Guidelines 

on Sustainability for Rehabilitating Historic Buildings. 

New Exterior Additions and Related New 

Construction 

Rehabilitation is the only treatment that allows expanding a historic 

building by enlarging it with an addition. However, the Rehabilita­

tion guidelines emphasize that new additions should be considered 

only after it is determined that meeting specific new needs cannot 

be achieved by altering non-character-defining interior spaces. If the 

use cannot be accommodated in this way, then an attached exterior 

addition may be considered. New additions should be designed and 

constructed so that the character-defining features of the historic 

building, its site, and setting are not negatively impacted. Generally, 

a new addition should be subordinate to the historic building. A new 

addition should be compatible, but differentiated enough so that 

it is not confused as historic or original to the building. The same 

guidance applies to new construction so that it does not negatively 

impact the historic character of the building or its site. 

Rehabilitation as a Treatment. When repair and replacement of 

deteriorated features are necessary; when alterations or additions to the 

property are planned for a new or continued use; and when its depiction 

at a particular time is not appropriate, Rehabilitation may be considered 

as a treatment. Prior to undertaking work, a documentation plan for 

Rehabilitation should be developed. 

INTRODUCTION 79
REHABILITATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining and preserving masonry features that are 

important in defining the overall historic character of the building (such as walls, brackets, railings, cornices, window and door 

surrounds, steps, and columns) and decorative ornament and 

other details, such as tooling and bonding patterns, coatings, and 

color. 

Removing or substantially changing masonry features which are 

important in defining the overall historic character of the building 

so that, as a result, the character is diminished. 

Replacing or rebuilding a major portion of exterior masonry walls 

that could be repaired, thereby destroying the historic integrity of 

the building. 

Applying paint or other coatings (such as stucco) to masonry that 

has been historically unpainted or uncoated to create a new appearance. 

Removing paint from historically-painted masonry. 

Protecting and maintaining masonry by ensuring that historic 

drainage features and systems that divert rainwater from masonry 

surfaces (such as roof overhangs, gutters, and downspouts) are 

intact and functioning properly. 

Failing to identify and treat the causes of masonry deterioration, 

such as leaking roofs and gutters or rising damp. 

Cleaning masonry only when necessary to halt deterioration or 

remove heavy soiling. 

Cleaning masonry surfaces when they are not heavily soiled to 

create a “like-new” appearance, thereby needlessly introducing 

chemicals or moisture into historic materials. 

Carrying out masonry cleaning tests when it has been determined Cleaning masonry surfaces without testing or without sufficient time 

that cleaning is appropriate. Test areas should be examined for the testing results to be evaluated. 

to ensure that no damage has resulted and, ideally, monitored 

over a sufficient period of time to allow long-range effects to be 

predicted. 

[1] An alkaline-based 

product is appropriate 

to use to clean historic 

marble because it will 

not damage the marble, 

which is acid sensitive. 

80 MASONRY 
REHABILITATION

[2] Mid-century modern 

building technology 

made possible the 

form of this parabolashaped structure and 

its thin concrete shell 

construction. Built in 

1961 as the lobby of 

the La Concha Motel 

in Las Vegas, it was 

designed by Paul 

Revere Williams, one 

of the first prominent 

African-American 

architects. It was moved 

to a new location and 

rehabilitated to serve 

as the Neon Museum, 

and is often cited as 

an example of Googie 

architecture. Credit: 

Photographed with 

permission at The Neon 

Museum, Las Vegas, 

Nevada. 

MASONRY 81
REHABILITATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Cleaning soiled masonry surfaces with the gentlest method possible, such as using low-pressure water and detergent and natural 

bristle or other soft-bristle brushes. 

Cleaning or removing paint from masonry surfaces using most 

abrasive methods (including sandblasting, other media blasting, or 

high-pressure water) which can damage the surface of the masonry 

and mortar joints. 

Using a cleaning or paint-removal method that involves water or 

liquid chemical solutions when there is any possibility of freezing 

temperatures. 

Cleaning with chemical products that will damage some types of 

masonry (such as using acid on limestone or marble), or failing to 

neutralize or rinse off chemical cleaners from masonry surfaces. 

[3] Not Recommended: 

The white film on the upper corner 

of this historic brick row house is 

the result of using a scrub or slurry 

coating, rather than traditional 

repointing by hand, which is the 

recommended method. 

[4] Not Recommended: 

The quoins on the left side of the 

photo show that high-pressure 

abrasive blasting used to remove 

paint can damage even early 20thcentury, hard-baked, textured brick 

and erode the mortar, whereas 

the same brick on the right, which 

was not abrasively cleaned, is 

undamaged. 

82 MASONRY 
REHABILITATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Using biodegradable or environmentally-safe cleaning or paintremoval products. 

Using paint-removal methods that employ a poultice to which 

paint adheres, when possible, to neatly and safely remove old 

lead paint. 

Using coatings that encapsulate lead paint, when possible, where 

the paint is not required to be removed to meet environmental 

regulations. 

Allowing only trained conservators to use abrasive or laser-cleaning methods, when necessary, to clean hard-to-reach, highlycarved, or detailed decorative stone features. 

Removing damaged or deteriorated paint only to the next sound 

layer using the gentlest method possible (e.g., hand scraping) 

prior to repainting. 

Removing paint that is firmly adhered to masonry surfaces, unless 

the building was unpainted historically and the paint can be 

removed without damaging the surface. 

Applying compatible paint coating systems to historically-painted 

masonry following proper surface preparation. 

Failing to follow manufacturers’ product and application instructions when repainting masonry features. 

Repainting historically-painted masonry features with colors 

that are appropriate to the historic character of the building and 

district. 

Using paint colors on historically-painted masonry features that are 

not appropriate to the historic character of the building and district. 

Protecting adjacent materials when cleaning or removing paint 

from masonry features. 

Failing to protect adjacent materials when cleaning or removing 

paint from masonry features. 

Evaluating the overall condition of the masonry to determine 

whether more than protection and maintenance, such as repairs 

to masonry features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

masonry features. 

Repairing masonry by patching, splicing, consolidating, or otherwise reinforcing the masonry using recognized preservation methods. Repair may include the limited replacement in kind or with 

a compatible substitute material of those extensively deteriorated 

or missing parts of masonry features when there are surviving 

prototypes, such as terra-cotta brackets or stone balusters. 

Removing masonry that could be stabilized, repaired, and conserved, or using untested consolidants and unskilled personnel, 

potentially causing further damage to historic materials. 

Replacing an entire masonry feature, such as a cornice or balustrade, when repair of the masonry and limited replacement of 

deteriorated or missing components are feasible. 

MASONRY 83
REHABILITATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Repairing masonry walls and other masonry features by repoint- Removing non-deteriorated mortar from sound joints and then 

ing the mortar joints where there is evidence of deterioration, repointing the entire building to achieve a more uniform appearsuch as disintegrating mortar, cracks in mortar joints, loose ance. 

bricks, or damaged plaster on the interior. 

Removing deteriorated lime mortar carefully by hand raking the 

joints to avoid damaging the masonry. 

Using power tools only on horizontal joints on brick masonry in 

conjunction with hand chiseling to remove hard mortar that is 

deteriorated or that is a non-historic material which is causing 

damage to the masonry units. Mechanical tools should be used 

only by skilled masons in limited circumstances and generally not 

on short, vertical joints in brick masonry. 

Allowing unskilled workers to use masonry saws or mechanical tools 

to remove deteriorated mortar from joints prior to repointing. 

Duplicating historic mortar joints in strength, composition, color, 

and texture when repointing is necessary. In some cases, a limebased mortar may also be considered when repointing Portland 

cement mortar because it is more flexible. 

Repointing masonry units with mortar of high Portland cement 

content (unless it is the content of the historic mortar). 

Using “surface grouting” or a “scrub” coating technique, such as 

a “sack rub” or “mortar washing,” to repoint exterior masonry units 

instead of traditional repointing methods. 

Repointing masonry units (other than concrete) with a synthetic 

caulking compound instead of mortar. 

Duplicating historic mortar joints in width and joint profile when 

repointing is necessary. 

Changing the width or joint profile when repointing. 

Repairing stucco by removing the damaged material and patching 

with new stucco that duplicates the old in strength, composition, 

color, and texture. 

Removing sound stucco or repairing with new stucco that is different in composition from the historic stucco. 

Patching stucco or concrete without removing the source of deterioration. 

Replacing deteriorated stucco with synthetic stucco, an exterior 

finish and insulation system (EFIS), or other non-traditional materials. 

84 MASONRY 
REHABILITATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Using mud plaster or a compatible lime-plaster adobe render, 

when appropriate, to repair adobe. 

Applying cement stucco, unless it already exists, to adobe. 

Sealing joints in concrete with appropriate flexible sealants and 

backer rods, when necessary. 

Cutting damaged concrete back to remove the source of deterioration, such as corrosion on metal reinforcement bars. The new 

patch must be applied carefully so that it will bond satisfactorily 

with and match the historic concrete. 

Patching damaged concrete without removing the source of deterioration. 

[5] Rebars in the reinforced concrete ceiling have rusted, causing the concrete 

to spall. The rebars must be cleaned of rust before the concrete can be patched. 

[6] Some areas of the concrete brise soleil screen on this building constructed in 

1967 are badly deteriorated. If the screen cannot be repaired, it may be replaced 

in kind or with a composite substitute material with the same appearance as the 

concrete. 

MASONRY 85
REHABILITATION

86

[7] (a) J.W. Knapp’s Department Store, built 1937-38, in Lansing, MI, was 

constructed with a proprietary material named “Maul Macotta” made of 

enameled steel and cast-in-place concrete panels. Prior to its rehabilitation, 

a building inspection revealed that, due to a flaw in the original design and 

construction, the material was deteriorated beyond repair. The architects for the 

rehabilitation project devised a replacement system (b) consisting of enameled 

aluminum panels that matched the original colors (c). Photos and drawing (a-b): 

Quinn Evans Architects; Photo (c): James Haefner Photography. 

MASONRY 
REHABILITATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Using a non-corrosive, stainless-steel anchoring system when 

replacing damaged stone, concrete, or terra-cotta units that have 

failed. 

Applying non-historic surface treatments, such as water-repellent 

coatings, to masonry only after repointing and only if masonry 

repairs have failed to arrest water penetration problems. 

Applying waterproof, water-repellent, or non-original historic coatings (such as stucco) to masonry as a substitute for repointing and 

masonry repairs. 

Applying permeable, anti-graffiti coatings to masonry when 

appropriate. 

Applying water-repellent or anti-graffiti coatings that change the 

historic appearance of the masonry or that may trap moisture if the 

coating is not sufficiently permeable. 

Replacing in kind an entire masonry feature that is too deteriorated to repair (if the overall form and detailing are still evident) 

using the physical evidence as a model to reproduce the feature 

or when the replacement can be based on historic documentation. Examples can include large sections of a wall, a cornice, 

pier, or parapet. If using the same kind of material is not feasible, 

then a compatible substitute material may be considered. 

Removing a masonry feature that is unrepairable and not replacing 

it, or replacing it with a new feature that does not match. 

Using substitute material for the replacement that does not convey 

the same appearance of the surviving components of the masonry 

feature. 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a replacement masonry feature, such as Creating an inaccurate appearance because the replacement for 

a step or door pediment, when the historic feature is completely the missing masonry feature is based upon insufficient physical or 

missing. It may be an accurate restoration based on documentary historic documentation, is not a compatible design, or because the 

and physical evidence, but only when the historic feature to be feature to be replaced did not coexist with the features currently on 

replaced coexisted with the features currently on the building. Or, the building. 

it may be a new design that is compatible with the size, scale, 

material, and color of the historic building. Introducing a new masonry feature that is incompatible in size, 

scale, material, or color. 

MASONRY 87
REHABILITATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND 

OTHER FUNCTIONAL AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining and preserving wood features that are 

important in defining the overall historic character of the building 

(such as siding, cornices, brackets, window and door surrounds, 

and steps) and their paints, finishes, and colors. 

Removing or substantially changing wood features which are important in defining the overall historic character of the building so that, 

as a result, the character is diminished. 

Removing a major portion of the historic wood from a façade 

instead of repairing or replacing only the deteriorated wood, then 

reconstructing the façade with new material to achieve a uniform or 

“improved” appearance. 

Changing the type of finish, coating, or historic color of wood features, thereby diminishing the historic character of the exterior. 

Failing to renew failing paint or other coatings that are historic 

finishes. 

Stripping historically-painted surfaces to bare wood and applying a 

clear finish rather than repainting. 

Stripping paint or other coatings to reveal bare wood, thereby 

exposing historically-coated surfaces to the effects of accelerated 

weathering. 

Removing wood siding (clapboards) or other covering (such as 

stucco) from log structures that were covered historically, which 

changes their historic character and exposes the logs to accelerated 

deterioration. 

Protecting and maintaining wood features by ensuring that historic drainage features that divert rainwater from wood surfaces 

(such as roof overhangs, gutters, and downspouts) are intact and 

functioning properly. 

Failing to identify and treat the causes of wood deterioration, such 

as faulty flashing, leaking gutters, cracks and holes in siding, deteriorated caulking in joints and seams, plant material growing too 

close to wood surfaces, or insect or fungal infestation. 

88 WOOD 
REHABILITATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND 

OTHER FUNCTIONAL AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Applying chemical preservatives or paint to wood features that 

are subject to weathering, such as exposed beam ends, outriggers, or rafter tails. 

Using chemical preservatives (such as creosote) which, unless they 

were used historically, can change the appearance of wood features. 

Implementing an integrated pest management plan to identify 

appropriate preventive measures to guard against insect damage, 

such as installing termite guards, fumigating, and treating with 

chemicals. 

Retaining coatings (such as paint) that protect the wood from 

moisture and ultraviolet light. Paint removal should be considered only when there is paint surface deterioration and as part 

of an overall maintenance program which involves repainting or 

applying other appropriate coatings. 

Stripping paint or other coatings from wood features without recoating. 

[8] Rotted clapboards 

have been replaced 

selectively with new 

wood siding to match the 

originals. 

WOOD 89
REHABILITATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND 

OTHER FUNCTIONAL AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Removing damaged or deteriorated paint to the next sound layer 

using the gentlest method possible (e.g., hand scraping and hand 

sanding) prior to repainting. 

Using potentially-damaging paint-removal methods on wood surfaces, such as open-flame torches, orbital sanders, abrasive methods (including sandblasting, other media blasting, or high-pressure 

water), or caustic paint-removers. 

Removing paint that is firmly adhered to wood surfaces. 

Using chemical strippers primarily to supplement other methods 

such as hand scraping, hand sanding, and thermal devices. 

Failing to neutralize the wood thoroughly after using chemical paint 

removers so that new paint may not adhere. 

Removing paint from detachable wood features by soaking them in 

a caustic solution, which may roughen the surface, split the wood, 

or result in staining from residual acids leaching out of the wood. 

Using biodegradable or environmentally-safe cleaning or paintremoval products. 

Using paint-removal methods that employ a poultice to which 

paint adheres, when possible, to neatly and safely remove old 

lead paint. 

Using thermal devices (such as infrared heaters) carefully to 

remove paint when it is so deteriorated that total removal is necessary prior to repainting. 

Using a thermal device to remove paint from wood features without 

first checking for and removing any flammable debris behind them. 

Using thermal devices without limiting the amount of time the wood 

feature is exposed to heat. 

Using coatings that encapsulate lead paint, when possible, where 

the paint is not required to be removed to meet environmental 

regulations. 

Applying compatible paint coating systems to historically-painted 

wood following proper surface preparation. 

Failing to follow manufacturers’ product and application instructions when repainting wood features. 

Repainting historically-painted wood features with colors that are 

appropriate to the building and district. 

Using paint colors on historically-painted wood features that are not 

appropriate to the building or district. 

90 WOOD 
REHABILITATION

 

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND 

OTHER FUNCTIONAL AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Protecting adjacent materials when working on other wood 

features. 

Failing to protect adjacent materials when working on wood features. 

Evaluating the overall condition of the wood to determine whether 

more than protection and maintenance, such as repairs to wood 

features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

wood features. 

[9] Smooth-surfaced cementitious 

siding (left) may be used to replace 

deteriorated wood siding only on 

secondary elevations that have 

minimal visibility. [10] Not Recommended: 

Cementitious siding with a raised 

wood-grain texture is not an 

appropriate material to replace 

historic wood siding, which has a 

smooth surface when painted. 

WOOD 91
REHABILITATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND 

OTHER FUNCTIONAL AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Repairing wood by patching, splicing, consolidating, or otherwise Removing wood that could be stabilized, repaired, and conserved, 

reinforcing the wood using recognized conservation methods. or using untested consolidants and unskilled personnel, potentially 

Repair may include the limited replacement in kind or with a causing further damage to historic materials. 

compatible substitute material of those extensively deteriorated 

or missing components of wood features when there are surviving Replacing an entire wood feature, such as a cornice or balustrade, 

prototypes, such as brackets, molding, or sections of siding. when repair of the wood and limited replacement of deteriorated or 

missing components is feasible. 

Replacing in kind an entire wood feature that is too deterio- Removing a wood feature that is unrepairable and not replacing it, 

rated to repair (if the overall form and detailing are still evident) or replacing it with a new feature that does not match. 

using physical evidence as a model to reproduce the feature or 

when the replacement can be based on historic documentation. Using substitute material for the replacement that does not convey 

Examples of such wood features include a cornice, entablature, the same appearance of the surviving components of the wood 

or a balustrade. If using wood is not feasible, then a compatible feature. 

substitute material may be considered. 

Replacing a deteriorated wood feature or wood siding on a primary or other highly-visible elevation with a new matching wood 

feature. 

Replacing a deteriorated wood feature or wood siding on a primary 

or other highly-visible elevation with a composite substitute material. 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a replacement masonry feature, such as Creating an inaccurate appearance because the replacement for 

a step or door pediment, when the historic feature is completely the missing masonry feature is based upon insufficient physical or 

missing. It may be an accurate restoration based on documentary historic documentation, is not a compatible design, or because the 

and physical evidence, but only when the historic feature to be feature to be replaced did not coexist with the features currently on 

replaced coexisted with the features currently on the building. Or, the building. 

it may be a new design that is compatible with the size, scale, 

material, and color of the historic building. Introducing a new wood feature that is incompatible in size, scale, 

material, or color. 

92 WOOD 
REHABILITATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving metal features that are Removing or substantially changing metal features which are imporimportant in defining the overall historic character of the building tant in defining the overall historic character of the building so that, 

(such as columns, capitals, pilasters, spandrel panels, or stair- as a result, the character is diminished. 

ways) and their paints, finishes, and colors. The type of metal 

should be identified prior to work because each metal has its own Removing a major portion of the historic metal from a façade 

properties and may require a different treatment. instead of repairing or replacing only the deteriorated metal, then 

reconstructing the façade with new material to achieve a uniform or 

“improved” appearance. 

Protecting and maintaining metals from corrosion by providing 

proper drainage so that water does not stand on flat, horizontal 

surfaces or accumulate in curved decorative features. 

Failing to identify and treat the causes of corrosion, such as moisture from leaking roofs or gutters. 

Placing incompatible metals together without providing an appropriate separation material. Such incompatibility can result in galvanic 

corrosion of the less noble metal (e.g., copper will corrode cast iron, 

steel, tin, and aluminum). 

Cleaning metals when necessary to remove corrosion prior to 

repainting or applying appropriate protective coatings. 

Leaving metals that must be protected from corrosion uncoated 

after cleaning. 

[11] The stainless steel 

doors at the entrance to 

this Art Deco apartment 

building are important 

in defining its historic 

character and should be 

retained in place. 

METALS 93
REHABILITATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Identifying the particular type of metal prior to any cleaning 

procedure and then testing to ensure that the gentlest cleaning 

method possible is selected; or, alternatively, determining that 

cleaning is inappropriate for the particular metal. 

Using cleaning methods which alter or damage the color, texture, 

or finish of the metal, or cleaning when it is inappropriate for the 

particular metal. 

Removing the patina from historic metals. The patina may be a 

protective layer on some metals (such as bronze or copper) as well 

as a distinctive finish. 

Using non-corrosive chemical methods to clean soft metals (such Cleaning soft metals (such as lead, tinplate, terneplate, copper, and 

as lead, tinplate, terneplate, copper, and zinc) whose finishes can zinc) with abrasive methods (including sandblasting, other abrasive 

be easily damaged by abrasive methods. media, or high-pressure water) which will damage the surface of the 

metal. 

Using the least abrasive cleaning method for hard metals (such Using high-pressure abrasive techniques (including sandblasting, 

as cast iron, wrought iron, and steel) to remove paint buildup and other media blasting, or high-pressure water) without first trying 

corrosion. If hand scraping and wire brushing have proven inef­ gentler cleaning methods prior to cleaning cast iron, wrought iron, 

fective, low-pressure abrasive methods may be used as long as or steel. 

they do not abrade or damage the surface. 

Applying appropriate paint or other coatings to historically-coated 

metals after cleaning to protect them from corrosion. 

Applying paint or other coatings to metals (such as copper, bronze 

or stainless steel) if they were not coated historically, unless a coating is necessary for maintenance. 

Repainting historically-painted metal features with colors that are 

appropriate to the building and district. 

Using paint colors on historically-painted metal features that are 

not appropriate to the building or district. 

Applying an appropriate protective coating (such as lacquer or 

wax) to a metal feature that was historically unpainted, such as a 

bronze door, which is subject to heavy use. 

94 METALS 
REHABILITATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Protecting adjacent materials when cleaning or removing paint 

from metal features. 

Failing to protect adjacent materials when working on metal features. 

Evaluating the overall condition of metals to determine whether 

more than protection and maintenance, such as repairs to metal 

features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

metal features. 

[12] This historic steel 

window has been 

cleaned, repaired, and 

primed in preparation for 

painting and reglazing. 

[13] The gold-colored, 

anodized aluminum geodesic 

dome of the former Citizen’s 

State Bank in Oklahoma 

City, OK, built in 1958 and 

designed by Robert Roloff, 

makes this a distinctive mid20th century building. 

METALS 95
REHABILITATION

96

[14] Interior cast-iron 

columns have been 

cleaned and repainted as 

part of the rehabilitation 

of this historic market 

building for continuing 

use. 

[15] New enameled-metal 

panels were replicated 

to replace the original 

panels, which were too 

deteriorated to repair, 

when the storefront of 

this early 1950s building 

was recreated. 

METALS 
REHABILITATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Repairing metal by reinforcing the metal using recognized preservation methods. Repair may include the limited replacement in 

kind or with a compatible substitute material of those extensively 

deteriorated or missing components of features when there are 

surviving prototypes, such as column capitals or bases, storefronts, railings and steps, or window hoods. 

Removing metals that could be stabilized, repaired, and conserved, 

or using improper repair techniques, or unskilled personnel, potentially causing further damage to historic materials. 

Replacing in kind an entire metal feature that is too deteriorated 

to repair (if the overall form and detailing are still evident) using 

the physical evidence as a model to reproduce the feature or 

when the replacement can be based on historic documentation. 

Examples of such a feature could include cast-iron porch steps or 

steel-sash windows. If using the same kind of material is not feasible, then a compatible substitute material may be considered. 

Replacing an entire metal feature, such as a column or balustrade, 

when repair of the metal and limited replacement of deteriorated or 

missing components are feasible. 

Removing a metal feature that is unrepairable and not replacing it, 

or replacing it with a new metal feature that does not match. 

Using a substitute material for the replacement that does not 

convey the same appearance of the surviving components of the 

metal feature or that is physically or chemically incompatible. 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a replacement metal feature, such as a Creating an inaccurate appearance because the replacement for the 

metal cornice or cast-iron column, when the historic feature is missing metal feature is based upon insufficient physical or historic 

completely missing. It may be an accurate restoration based on documentation, is not a compatible design, or because the feature 

documentary and physical evidence, but only when the historic to be replaced did not coexist with the features currently on the 

feature to be replaced coexisted with the features currently on building. 

the building. Or, it may be a new design that is compatible with 

the size, scale, material, and color of the historic building. Introducing a new metal feature that is incompatible in size, scale, 

material, or color. 

METALS 97
REHABILITATION

ROOFS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving roofs and their functional 

and decorative features that are important in defining the overall 

historic character of the building. The form of the roof (gable, 

hipped, gambrel, flat, or mansard) is significant, as are its decorative and functional features (such as cupolas, cresting, parapets, monitors, chimneys, weather vanes, dormers, ridge tiles, 

and snow guards), roofing material (such as slate, wood, clay 

tile, metal, roll roofing, or asphalt shingles), and size, color, and 

patterning. 

Removing or substantially changing roofs which are important in 

defining the overall historic character of the building so that, as a 

result, the character is diminished. 

Removing a major portion of the historic roof or roofing material 

that is repairable, then rebuilding it with new material to achieve a 

more uniform or “improved” appearance. 

Changing the configuration or shape of a roof by adding highly visible new features (such as dormer windows, vents, skylights, or a 

penthouse). 

Stripping the roof of sound historic material, such as slate, clay tile, 

wood, or metal. 

Protecting and maintaining a roof by cleaning gutters and Failing to clean and maintain gutters and downspouts properly so 

downspouts and replacing deteriorated flashing. Roof sheathing that water and debris collect and cause damage to roof features, 

should also be checked for indications of moisture due to leaks or sheathing, and the underlying roof structure. 

condensation. 

Providing adequate anchorage for roofing material to guard 

against wind damage and moisture penetration. 

Allowing flashing, caps, and exposed fasteners to corrode, which 

accelerates deterioration of the roof. 

Protecting a leaking roof with a temporary waterproof membrane 

with a synthetic underlayment, roll roofing, plywood, or a tarpaulin until it can be repaired. 

Leaving a leaking roof unprotected so that accelerated deterioration of historic building materials (such as masonry, wood, plaster, 

paint, and structural members) occurs. 

Repainting a roofing material that requires a protective coating 

and was painted historically (such as a terneplate metal roof or 

gutters) as part of regularly-scheduled maintenance. 

Failing to repaint a roofing material that requires a protective 

coating and was painted historically as part of regularly-scheduled 

maintenance. 

Applying compatible paint coating systems to historically-painted 

roofing materials following proper surface preparation. 

Applying paint or other coatings to roofing material if they were not 

coated historically. 

Protecting a roof covering when working on other roof features. Failing to protect roof coverings when working on other roof features. 

Evaluating the overall condition of the roof and roof features to 

determine whether more than protection and maintenance, such 

as repairs to roof features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

roof features. 

98 ROOFS 
REHABILITATION

ROOFS 

RECOMMENDED NOT RECOMMENDED 

Repairing a roof by ensuring that the existing historic or compat- Replacing an entire roof feature when repair of the historic roofible non-historic roof covering is sound and waterproof. Repair ing materials and limited replacement of deteriorated or missing 

may include the limited replacement in kind or with a compatible components are feasible. 

substitute material of missing materials (such as wood shingles, 

slates, or tiles) on a main roof, as well as those extensively 

deteriorated or missing components of features when there are 

surviving prototypes, such as ridge tiles, dormer roofing, or roof 

monitors. 

Using corrosion-resistant roof fasteners (e.g., nails and clips) to 

repair a roof to help extend its longevity. 

[16] The deteriorated asphalt shingles 

of this porch roof are being replaced in 

kind with matching shingles. 

ROOFS 99
REHABILITATION

ROOFS 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire roof covering or feature that is too Removing a feature of the roof that is unrepairable and not replacdeteriorated to repair (if the overall form and detailing are still ing it, or replacing it with a new roof feature that does not match. 

evident) using the physical evidence as a model to reproduce 

the feature or when the replacement can be based on historic Using a substitute material for the replacement that does not 

documentation. Examples of such a feature could include a large convey the same appearance of the roof covering or the surviving 

section of roofing, a dormer, or a chimney. If using the same kind components of the roof feature or that is physically or chemically 

of material is not feasible, then a compatible substitute material incompatible. 

may be considered. 

Replacing only missing or damaged roofing tiles or slates rather 

than replacing the entire roof covering. 

Failing to reuse intact slate or tile in good condition when only the 

roofing substrate or fasteners need replacement. 

Replacing an incompatible roof covering or any deteriorated nonhistoric roof covering with historically-accurate roofing material, 

if known, or another material that is compatible with the historic 

character of the building. 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a new roof covering for a missing roof or Creating an inaccurate appearance because the replacement for the 

a new feature, such as a dormer or a monitor, when the historic missing roof feature is based upon insufficient physical or historic 

feature is completely missing. It may be an accurate restoration documentation, is not a compatible design, or because the feature 

based on documentary and physical evidence, but only when to be replaced did not coexist with the features currently on the 

the historic feature to be replaced coexisted with the features building. 

currently on the building. Or, it may be a new design that is 

compatible with the size, scale, material, and color of the historic Introducing a new roof feature that is incompatible in size, scale, 

building. material, or color. 

100 ROOFS 
REHABILITATION

ROOFS 

RECOMMENDED NOT RECOMMENDED 

Alterations and Additions for a New Use 

Installing mechanical and service equipment on the roof (such 

as heating and air-conditioning units, elevator housing, or solar 

panels) when required for a new use so that they are inconspicuous on the site and from the public right-of-way and do not 

damage or obscure character-defining historic features. 

Installing roof-top mechanical or service equipment so that it damages or obscures character-defining roof features or is conspicuous 

on the site or from the public right-of-way. 

Designing rooftop additions, elevator or stair towers, decks or terraces, dormers, or skylights when required by a new or continuing use so that they are inconspicuous and minimally visible on 

the site and from the public right-of-way and do not damage or 

obscure character-defining historic features. 

Changing a character-defining roof form, or damaging or destroying 

character-defining roofing material as a result of an incompatible 

rooftop addition or improperly-installed or highly-visible mechanical 

equipment. 

Installing a green roof or other roof landscaping, railings, or 

furnishings that are not visible on the site or from the public 

right-of-way and do not damage the roof structure. 

Installing a green roof or other roof landscaping, railings, or furnishings that are visible on the site and from the public right-of-way. 

[17] New wood 

elements have been 

used selectively to 

replace rotted wood 

on the underside of 

the roof in this historic 

warehouse. 

ROOFS 101
REHABILITATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving windows and their func- Removing or substantially changing windows or window features 

tional and decorative features that are important to the overall which are important in defining the overall historic character of the 

character of the building. The window material and how the building so that, as a result, the character is diminished. 

window operates (e.g., double hung, casement, awning, or 

hopper) are significant, as are its components (including sash, Changing the appearance of windows that contribute to the historic 

muntins, ogee lugs, glazing, pane configuration, sills, mullions, character of the building by replacing materials, finishes, or colors 

casings, or brick molds) and related features, such as shutters. which noticeably change the sash, depth of the reveal, and muntin 

configurations; the reflectivity and color of the glazing; or the 

appearance of the frame. 

Obscuring historic wood window trim with metal or other material. 

Replacing windows solely because of peeling paint, broken glass, 

stuck sash, or high air infiltration. These conditions, in themselves, 

do not indicate that windows are beyond repair. 

Protecting and maintaining the wood or metal which comprises Failing to protect and maintain window materials on a cyclical basis 

the window jamb, sash, and trim through appropriate treatments, so that deterioration of the window results. 

such as cleaning, paint removal, and reapplication of protective 

coating systems. 

Protecting windows against vandalism before work begins by 

covering them and by installing alarm systems that are keyed into 

local protection agencies. 

Leaving windows unprotected and subject to vandalism before work 

begins, thereby also allowing the interior to be damaged if it can be 

accessed through unprotected windows. 

Making windows weathertight by recaulking gaps in fixed joints 

and replacing or installing weatherstripping. 

Protecting windows from chemical cleaners, paint, or abrasion 

during work on the exterior of the building. 

Failing to protect historic windows from chemical cleaners, paint, or 

abrasion when work is being done on the exterior of the building. 

Protecting and retaining historic glass when replacing putty or 

repairing other components of the window. 

Failing to protect the historic glass when making window repairs. 

102 WINDOWS 
REHABILITATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

Sustaining the historic operability of windows by lubricating 

friction points and replacing broken components of the operating system (such as hinges, latches, sash chains or cords) and 

replacing deteriorated gaskets or insulating units. 

Failing to maintain windows and window components so that windows are inoperable, or sealing operable sash permanently. 

Failing to repair and reuse window hardware such as sash lifts, 

latches, and locks. 

Adding storm windows with a matching or a one-over-one pane 

configuration that will not obscure the characteristics of the historic windows. Storm windows improve energy efficiency and are 

especially beneficial when installed over wood windows because 

they also protect them from accelerated deterioration. 

Adding interior storm windows as an alternative to exterior storm 

windows when appropriate. 

[18] The historic metal 

storm windows in this 

1920s office building 

were retained and 

repaired during the 

rehabilitation project. 

[19] Installing a 

mockup of a proposed 

replacement window 

can be helpful to 

evaluate how well the 

new windows will match 

the historic windows 

that are missing or too 

deteriorated to repair. 

WINDOWS 103
REHABILITATION

104

[20 a-d] The original steel windows 

in this industrial building were 

successfully repaired as part of the 

rehabilitation project (left). 

WINDOWS 
REHABILITATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

Installing sash locks, window guards, removable storm windows, 

and other reversible treatments to meet safety, security, or energy 

conservation requirements. 

Evaluating the overall condition of the windows to determine 

whether more than protection and maintenance, such as repairs 

to windows and window features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

window features. 

Repairing window frames and sash by patching, splicing, consoli- Removing window features that could be stabilized, repaired, or 

dating, or otherwise reinforcing them using recognized preserva­ conserved using untested consolidants, improper repair techniques, 

tion methods. Repair may include the limited replacement in or unskilled personnel, potentially causing further damage to the 

kind or with a compatible substitute material of those extensively historic materials. 

deteriorated, broken, or missing components of features when 

there are surviving prototypes, such as sash, sills, hardware, or Replacing an entire window when repair of the window and limited 

shutters. replacement of deteriorated or missing components are feasible. 

Removing glazing putty that has failed and applying new putty; 

or, if glass is broken, carefully removing all putty, replacing the 

glass, and reputtying. 

Installing new glass to replace broken glass which has the same 

visual characteristics as the historic glass. 

Replacing in kind an entire window that is too deteriorated to Removing a character-defining window that is unrepairable or is not 

repair (if the overall form and detailing are still evident) using needed for the new use and blocking up the opening, or replacing it 

the physical evidence as a model to reproduce the feature or with a new window that does not match. 

when the replacement can be based on historic documentation. 

If using the same kind of material is not feasible, then a compat- Using substitute material for the replacement that does not convey 

ible substitute material may be considered. the same appearance of the surviving components of the window or 

that is physically incompatible. 

WINDOWS 105
REHABILITATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

[21] The windows on the 

lower floor, which were 

too deteriorated to repair, 

were replaced with new 

steel windows matching 

the upper-floor historic 

windows that were 

retained. 

Modifying a historic single-glazed sash to accommodate insulated 

glass when it will not jeopardize the soundness of the sash or 

significantly alter its appearance. 

Modifying a historic single-glazed sash to accommodate insulated 

glass when it will jeopardize the soundness of the sash or significantly alter its appearance. 

Using low-e glass with the least visible tint in new or replacement 

windows. 

Using low-e glass with a dark tint in new or replacement windows, 

thereby negatively impacting the historic character of the building. 

Using window grids rather than true divided lights on windows on Using window grids rather than true divided lights on windows in 

the upper floors of high-rise buildings if they will not be notice­ low-rise buildings or on lower floors of high-rise buildings where 

able. they will be noticeable, resulting in a change to the historic character of the building. 

Ensuring that spacer bars in between double panes of glass are 

the same color as the window sash. 

Using spacer bars in between double panes of glass that are not the 

same color as the window sash. 

Replacing all of the components in a glazing system if they have 

failed because of faulty design or materials that have deteriorated 

with new material that will improve the window performance 

without noticeably changing the historic appearance. 

Replacing all of the components in a glazing system with new material that will noticeably change the historic appearance. 

Replacing incompatible, non-historic windows with new windows 

that are compatible with the historic character of the building; or 

reinstating windows in openings that have been filled in. 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a new window or its components, such Creating an inaccurate appearance because the replacement for the 

as frames, sash, and glazing, when the historic feature is com- missing window is based upon insufficient physical or historic docupletely missing. It may be an accurate restoration based on mentation, is not a compatible design, or because the feature to be 

documentary and physical evidence, but only when the historic replaced did not coexist with the features currently on the building. 

feature to be replaced coexisted with the features currently on 

the building. Or, it may be a new design that is compatible with Installing replacement windows made from other materials that are 

the size, scale, material, and color of the historic building. not the same as the material of the original windows if they would 

have a noticeably different appearance from the remaining historic 

windows. 

106 WINDOWS 
REHABILITATION

(b) (a) 

(c) 

[22] Not Recommended: (a-b) The original wood windows in this late-19th-century 

building, which were highly decorative, could likely have been repaired and retained. 

(c) Instead, they were replaced with new windows that do not match the detailing of 

the historic windows and, therefore, do not meet the Standards (above). 

(b) 

WINDOWS 107
REHABILITATION

108

[23] (a)This deteriorated 

historic wood window 

was repaired and 

retained (b) in this 

rehabilitation project. 

WINDOWS 
REHABILITATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

Alterations and Additions for a New Use 

Adding new window openings on rear or other secondary, lessvisible elevations, if required by a new use. The new openings 

and the windows in them should be compatible with the overall 

design of the building but, in most cases, not duplicate the 

historic fenestration. 

Changing the number, location, size, or glazing pattern of windows 

on primary or highly-visible elevations which will alter the historic 

character of the building. 

Cutting new openings on character-defining elevations or cutting 

new openings that damage or destroy significant features. 

Adding balconies at existing window openings or new window openings on primary or other highly-visible elevations where balconies 

never existed and, therefore, would be incompatible with the historic character of the building. 

Replacing windows that are too deteriorated to repair using the Replacing a window that contributes to the historic character of 

same sash and pane configuration, but with new windows that the building with a new window that is different in design (such as 

operate differently, if necessary, to accommodate a new use. glass divisions or muntin profiles), dimensions, materials (wood, 

Any change must have minimal visual impact. Examples could metal, or glass), finish or color, or location that will have a noticeinclude replacing hopper or awning windows with casement ably different appearance from the historic windows, which may 

windows, or adding a realigned and enlarged operable portion of negatively impact the character of the building. 

industrial steel windows to meet life-safety codes. 

Installing impact-resistant glazing, when necessary for security, 

so that it is compatible with the historic windows and does not 

damage them or negatively impact their character. 

Installing impact-resistant glazing, when necessary for security, that 

is incompatible with the historic windows and that damages them 

or negatively impacts their character. 

Using compatible window treatments (such as frosted glass, Removing a character-defining window to conceal mechanical 

appropriate shades or blinds, or shutters) to retain the historic equipment or to provide privacy for a new use of the building by 

character of the building when it is necessary to conceal mechan­ blocking up the opening. 

ical equipment, for example, that the new use requires be placed 

in a location behind a window or windows on a primary or highlyvisible elevation. 

WINDOWS 109
REHABILITATION

ENTRANCES AND PORCHES 

RECOMMENDED NOT RECOMMENDED 

[24] Rotted boards 

in the beaded-board 

porch ceiling are being 

replaced with new 

matching beaded board. 

Identifying, retaining, and preserving entrances and porches and 

their functional and decorative features that are important in 

defining the overall historic character of the building. The materials themselves (including masonry, wood, and metal) are significant, as are their features, such as doors, transoms, pilasters, 

columns, balustrades, stairs, roofs, and projecting canopies. 

Removing or substantially changing entrances and porches which 

are important in defining the overall historic character of the building so that, as a result, the character is diminished. 

Cutting new entrances on a primary façade. 

Altering utilitarian or service entrances so they compete visually 

with the historic primary entrance; increasing their size so that they 

appear significantly more important; or adding decorative details 

that cannot be documented to the building or are incompatible with 

the building’s historic character. 

Retaining a historic entrance or porch even though it will no 

longer be used because of a change in the building’s function. 

Removing a historic entrance or porch that will no longer be 

required for the building’s new use. 

Protecting and maintaining the masonry, wood, and metals which 

comprise entrances and porches through appropriate surface 

treatments, such as cleaning, paint removal, and reapplication of 

protective coating systems. 

Failing to protect and maintain entrance and porch materials on a 

cyclical basis so that deterioration of entrances and porches results. 

Protecting entrances and porches against arson and vandalism 

before work begins by covering them and by installing alarm 

systems keyed into local protection agencies. 

Leaving entrances and porches unprotected and subject to vandalism before work begins, thereby also allowing the interior to be 

damaged if it can be accessed through unprotected entrances. 

Protecting entrance and porch features when working on other 

features of the building. 

Failing to protect materials and features when working on other 

features of the building. 

Evaluating the overall condition of entrances and porches to 

determine whether more than protection and maintenance, such 

as repairs to entrance and porch features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

entrance and porch features. 

Repairing entrances and porches by patching, splicing, consoli- Removing entrances and porches that could be stabilized, repaired, 

dating, and otherwise reinforcing them using recognized preser­ and conserved, or using untested consolidants, improper repair 

vation methods. Repair may include the limited replacement in techniques, or unskilled personnel, potentially causing further 

kind or with a compatible substitute material of those extensively damage to historic materials. 

deteriorated features or missing components of features when 

there are surviving prototypes, such as balustrades, columns, and Replacing an entire entrance or porch feature when repair of the 

stairs. feature and limited replacement of deteriorated or missing components are feasible. 

110 ENTRANCES AND PORCHES 
REHABILITATION

ENTRANCES AND PORCHES 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire entrance or porch that is too deterio- Removing an entrance or porch that is unrepairable and not replacrated to repair (if the overall form and detailing are still evident) ing it, or replacing it with a new entrance or porch that does not 

using the physical evidence as a model to reproduce the feature match. 

or when the replacement can be based on historic documentation. If using the same kind of material is not feasible, then a Using a substitute material for the replacement that does not 

compatible substitute material may be considered. convey the same appearance of the surviving components of 

entrance or porch features or that is physically incompatible. 

[25] The new infill 

designs for the garage 

door openings in this 

commercial building (a) 

converted for restaurant 

use and in this mill 

building (b) rehabilitated 

for residential use are 

compatible with the 

historic character of the 

buildings. 

ENTRANCES AND PORCHES 111
REHABILITATION

ENTRANCES AND PORCHES 

RECOMMENDED NOT RECOMMENDED 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a new entrance or porch when the Creating an inaccurate appearance because the replacement for 

historic feature is completely missing or has previously been the missing entrance or porch is based upon insufficient physical or 

replaced by one that is incompatible. It may be an accurate res- historic documentation, is not a compatible design, or because the 

toration based on documentary and physical evidence, but only feature to be replaced did not coexist with the features currently on 

when the historic entrance or porch to be replaced coexisted with the building. 

the features currently on the building. Or, it may be a new design 

that is compatible with the size, scale, material, and color of the 

historic building. 

Alterations and Additions for a New Use 

Enclosing historic porches on secondary elevations only, when Enclosing porches in a manner that results in a diminution or loss 

required by a new use, in a manner that preserves the historic of historic character by using solid materials rather than clear glazcharacter of the building (e.g., using large sheets of glass and ing, or by placing the enclosure in front of, rather than behind, the 

recessing the enclosure wall behind existing posts and balus­ historic features. 

trades). 

Designing and constructing additional entrances or porches on 

secondary elevations when required for the new use in a manner 

that preserves the historic character of the building (i.e., ensuring 

that the new entrance or porch is clearly subordinate to historic 

primary entrances or porches). 

Constructing secondary or service entrances and porches that are 

incompatible in size and scale or detailing with the historic building 

or that obscure, damage, or destroy character-defining features. 

[26] Not Recommended: Installing a screened 

enclosure is never recommended on a front or 

otherwise prominent historic porch. In limited 

instances, it may be possible to add screening on a 

porch at the rear or on a secondary façade; however, 

the enclosure should match the color of the porch and 

be placed behind columns and railings so that it does 

not obscure these features. 

112 ENTRANCES AND PORCHES 
REHABILITATION

STOREFRONTS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving storefronts and their func- Removing or substantially changing storefronts and their features 

tional and decorative features that are important in defining the which are important in defining the overall historic character of the 

overall historic character of the building. The storefront materials building so that, as a result, the character is diminished. 

(including wood, masonry, metals, ceramic tile, clear glass, and 

pigmented structural glass) and the configuration of the store- Changing the storefront so that it has a residential rather than comfront are significant, as are features, such as display windows, mercial appearance. 

base panels, bulkheads, signs, doors, transoms, kick plates, 

corner posts, piers, and entablatures. The removal of inappropri- Introducing features from an earlier period that are not compatible 

ate, non-historic cladding, false mansard roofs, and other later, with the historic character of the storefront. 

non-significant alterations can help reveal the historic character 

of the storefront. Changing the location of the storefront’s historic main entrance. 

Replacing or covering a glass transom with solid material or inappropriate signage, or installing an incompatible awning over it. 

Retaining later, non-original features that have acquired significance over time. Removing later features that may have acquired significance. 

[28] This new storefront, 

which replaced one 

that was missing, is 

compatible with the 

historic character of the 

building. 

STOREFRONTS 113
REHABILITATION

STOREFRONTS 

RECOMMENDED NOT RECOMMENDED 

Protecting and maintaining masonry, wood, glass, ceramic tile, 

and metals which comprise storefronts through appropriate 

treatments, such as cleaning, paint removal, and reapplication of 

protective coating systems. 

Failing to protect and maintain storefront materials on a cyclical 

basis so that deterioration of storefront features results. 

Protecting storefronts against arson and vandalism before work 

begins by covering windows and doors and by installing alarm 

systems keyed into local protection agencies. 

Leaving the storefront unprotected and subject to vandalism before 

work begins, thereby also allowing the interior to be damaged if it 

can be accessed through unprotected entrances. 

Protecting the storefront when working on other features of the 

building. 

Failing to protect the storefront when working on other features of 

the building. 

Evaluating the overall condition of the storefront to determine 

whether more than protection and maintenance, such as repairs 

to storefront features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

storefront features. 

[27] This original c. 1940s 

storefront, with its characterdefining angled and curved 

glass display window and 

recessed entrance with a 

decorative terrazzo paving, is 

in good condition and should 

be retained in a rehabilitation 

project. 

114 STOREFRONTS 
REHABILITATION

STOREFRONTS 

RECOMMENDED NOT RECOMMENDED 

Repairing storefronts by patching, splicing, consolidating, or Removing storefronts that could be stabilized, repaired, and conotherwise reinforcing them using recognized preservation meth­ served, or using untested consolidants, improper repair techniques, 

ods. Repair may include the limited replacement in kind or with or unskilled personnel, potentially causing further damage to 

a compatible substitute material of those extensively deteriorated historic materials. 

or missing components of storefronts when there are surviving 

prototypes, such as transoms, base panels, kick plates, piers, or 

signs. 

Replacing in kind an entire storefront that is too deteriorated to 

repair (if the overall form and detailing are still evident) using 

the physical evidence as a model to reproduce the feature or 

when the replacement can be based on historic documentation. 

If using the same kind of material is not feasible, then a compatible substitute material may be considered. 

Replacing a storefront feature when repair of the feature and 

limited replacement of deteriorated or missing components are 

feasible. 

Using a substitute material for the replacement that does not 

convey the same appearance of the surviving components of the 

storefront or that is physically incompatible. 

Removing a storefront that is unrepairable and not replacing it or 

replacing it with a new storefront that does not match. 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a new storefront when the historic Creating an inaccurate appearance because the replacement for 

storefront is completely missing or has previously been replaced the missing storefront is based upon insufficient physical or historic 

by one that is incompatible. It may be an accurate restoration documentation, is not a compatible design, or because the feature 

based on documentary and physical evidence, but only when to be replaced did not coexist with the features currently on the 

the historic storefront to be replaced coexisted with the features building. 

currently on the building. Or, it may be a new design that is 

compatible with the size, scale, material, and color of the historic Using new, over-scaled, or internally-lit signs unless there is a hisbuilding. toric precedent for them or using other types of signs that obscure, 

damage, or destroy character-defining features of the storefront and 

the building. 

STOREFRONTS 115
REHABILITATION

STOREFRONTS 

RECOMMENDED NOT RECOMMENDED 

Replacing missing awnings or canopies that can be historically Adding vinyl awnings, or other awnings that are inappropriately 

documented to the building, or adding new signage, awnings, or sized or shaped, which are incompatible with the historic character 

canopies that are compatible with the historic character of the of the building; awnings that do not extend over the entire length of 

building. the storefront; or large canopies supported by posts that project out 

over the sidewalk, unless their existence can be historically documented. 

Alterations and Additions for a New Use 

Retaining the glazing and the transparency (i.e., which allows the Replacing storefront glazing with solid material for occupants’ priopenness of the interior to be experienced from the exterior) that vacy when the building is being converted for residential use. 

is so important in defining the character of a historic storefront 

when the building is being converted for residential use. Window Installing window treatments in storefront windows that have a resitreatments (necessary for occupants’ privacy) should be installed dential appearance, which are incompatible with the commercial 

that are uniform and compatible with the commercial appearance character of the building. 

of the building, such as screens or wood blinds. When display 

cases still exist behind the storefront, the screening should be set Installing window treatments that are not uniform in a series of 

at the back of the display case. repetitive storefront windows. 

[29] The rehabilitation of the 1910 Ma’alaea ­ General 

Store (a), which served the workers’ camp at the 

Wailuku Sugar Company on the Hawaiian island of Maui, 

included the reconstruction of the original parapet (b). 

116 STOREFRONTS 
REHABILITATION

CURTAIN WALLS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving curtain wall systems and Removing or substantially changing curtain wall components which 

their components (metal framing members and glass or opaque are important in defining the overall historic character of the buildpanels) that are important in defining the overall historic charac­ ing so that, as a result, the character is diminished. 

ter of the building. The design of the curtain wall is significant, 

as are its component materials (metal stick framing and panel Replacing historic curtain wall features instead of repairing or 

materials, such as clear or spandrel glass, stone, terra cotta, replacing only the deteriorated components. 

metal, and fiber-reinforced plastic), appearance (e.g., glazing 

color or tint, transparency, and reflectivity), and whether the glazing is fixed, operable or louvered glass panels. How a curtain wall 

is engineered and fabricated, and the fact that it expands and 

contracts at a different rate from the building’s structural system, 

are important to understand when undertaking the rehabilitation 

of a curtain wall system. 

Protecting and maintaining curtain walls and their components Failing to protect and maintain curtain wall components on a cyclithrough appropriate surface treatments, such as cleaning, paint cal basis so that deterioration of curtain walls results. 

removal, and reapplication of protective coating systems; and by 

making them watertight and ensuring that sealants and gaskets Failing to identify, evaluate, and treat various causes of curtain wall 

are in good condition. failure, such as open gaps between components where sealants 

have deteriorated or are missing. 

Protecting ground-level curtain walls from vandalism before work 

begins by covering them, while ensuring adequate ventilation, 

and by installing alarm systems keyed into local protection 

agencies. 

Leaving ground-level curtain walls unprotected and subject to vandalism before work begins, thereby also allowing the interior to be 

damaged if it can be accessed through unprotected glazing. 

Protecting curtain walls when working on other features of the 

building. 

Failing to protect curtain walls when working on other features of 

the building. 

Cleaning curtain wall systems only when necessary to halt deterioration or to remove heavy soiling. Cleaning curtain wall systems when they are not heavily soiled, 

thereby needlessly introducing chemicals or moisture into historic 

materials. 

CURTAIN WALLS 117
REHABILITATION

CURTAIN WALLS 

RECOMMENDED NOT RECOMMENDED 

Carrying out cleaning tests, when it has been determined that 

cleaning is appropriate, using only cleaning materials that will 

not damage components of the system, including factory-applied 

finishes. Test areas should be examined to ensure that no 

damage has resulted. 

Cleaning curtain wall systems without testing or using cleaning 

materials that may damage components of the system. 

Evaluating the overall condition of curtain walls to determine 

whether more than protection and maintenance, such as repair of 

curtain wall components, will be necessary. 

Failing to undertake adequate measures to protect curtain wall 

components. 

Repairing curtain walls by ensuring that they are watertight by Removing curtain wall components that could be repaired or using 

augmenting existing components or replacing deteriorated or improper repair techniques. 

missing sealants or gaskets, where necessary, to seal any gaps 

between system components. Repair may include the limited Replacing an entire curtain wall system when repair of materials 

replacement of those extensively deteriorated or missing compo­ and limited replacement of deteriorated or missing components are 

nents of curtain walls when there are surviving prototypes. feasible. 

Applying sealants carefully so that they are not readily visible. 

Replacing in kind a component or components of a curtain wall Removing a curtain wall component or the entire system, if necessystem that are too deteriorated to repair (if the overall form and sary, that is unrepairable and not replacing it or replacing it with a 

detailing are still evident) using the physical evidence as a model new component or system that does not convey the same appearto reproduce the feature. If using the same kind of material is not ance. 

feasible, then a compatible substitute material may be considered as long as it has the same finish and appearance. 

Replacing masonry, metal, glass, or other components of a Using substitute material for the replacement that does not convey 

curtain wall system (or the entire system, if necessary) which the same appearance of the surviving components of the curtain 

have failed because of faulty design with substitutes that match wall or that is physically incompatible. 

the original as closely as possible and which will reestablish the 

viability and performance of the system. 

118 CURTAIN WALLS 
REHABILITATION

[30] Rather than replace the original curtain wall system of the 1954 Simms 

Building in Albuquerque, NM, with a different color tinted glass or coat it with a nonhistoric reflective film, the HVAC system was updated to improve energy efficiency. 

Photo: Harvey M. Kaplan. 

[31 a-c:] (a) The 

rehabilitation of the 

First Federal Savings 

and Loan Association 

building in Birmingham, 

AL, constructed in 1961, 

required replacing the 

deteriorated historic 

curtain wall system 

because the framing and 

the fasteners holding 

the spandrel glass 

and the windows had 

failed. (b) Comparative 

drawings show that the 

differences between the 

replacement system, 

which incorporated new 

insulated glass to meet 

wind-load requirements, 

and the original system 

are minimal. (c) The 

replacement system, 

shown after completion 

of the project, has not 

altered the historic 

character of the building. 

CURTAIN WALLS 119
REHABILITATION

CURTAIN WALLS 

RECOMMENDED NOT RECOMMENDED 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a new curtain wall or its components Creating an inaccurate appearance because the replacement for 

when the historic feature is completely missing. It may be an the missing curtain wall component is based upon insufficient 

accurate restoration based on documentary and physical evi­ physical or historic documentation, is not a compatible design, or 

dence, but only when the historic feature to be replaced coex­ because the feature did not coexist with the features currently on 

isted with the features currently on the building. Or, it may be a the building. 

new design that is compatible with the size, scale, material, and 

color of the historic building. Introducing a new curtain wall component that is incompatible in 

size, scale, material, color, and finish. 

Alterations and Additions for a New Use 

Installing new glazing or an entire new curtain wall system, when 

necessary to meet safety-code requirements, with dimensions, 

detailing, materials, colors, and finish as close as possible to the 

historic curtain wall components. 

Installing new glazing or an entire new curtain wall system, when 

necessary to meet safety-code requirements, with dimensions and 

detailing that is significantly different from the historic curtain wall 

components. 

Installing impact-resistant glazing, when necessary for security, 

so that it is compatible with the historic windows and does not 

damage them or negatively impact their character. 

Installing impact-resistant glazing in a curtain wall system, when 

necessary for security, that is incompatible with the historic curtain 

walls and damages them or negatively impacts their character. 

120 CURTAIN WALLS 
REHABILITATION

STRUCTURAL SYSTEMS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving structural systems and visible features of systems that are important in defining the overall 

historic character of the building. This includes the materials that 

comprise the structural system (i.e., wood, metal and masonry), 

the type of system, and its features, such as posts and beams, 

trusses, summer beams, vigas, cast-iron or masonry columns, 

above-grade stone foundation walls, or load-bearing masonry 

walls. 

Removing or substantially changing visible features of historic 

structural systems which are important in defining the overall historic character of the building so that, as a result, the character is 

diminished. 

Overloading the existing structural system, or installing equipment 

or mechanical systems which could damage the structure. 

Replacing a load-bearing masonry wall that could be augmented 

and retained. 

Leaving known structural problems untreated, such as deflected 

beams, cracked and bowed walls, or racked structural members. 

Protecting and maintaining the structural system by keeping Failing to protect and maintain the structural system on a cyclical 

gutters and downspouts clear and roofing in good repair; and basis so that deterioration of the structural system results. 

by ensuring that wood structural members are free from insect 

infestation. Using treatments or products that may retain moisture, which 

accelerates deterioration of structural members. 

[33] Retaining as much 

as possible of the 

historic wood sill plate 

and replacing only the 

termite-damaged wood is 

always the preferred and 

recommended treatment. 

STRUCTURAL SYSTEMS 121
REHABILITATION

STRUCTURAL SYSTEMS 

RECOMMENDED NOT RECOMMENDED 

Evaluating the overall condition of the structural system to determine whether more than protection and maintenance, such as 

repairs to structural features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

structural systems. 

Repairing the structural system by augmenting individual components, using recognized preservation methods. For example, 

weakened structural members (such as floor framing) can be 

paired or sistered with a new member, braced, or otherwise 

supplemented and reinforced. 

Upgrading the building structurally in a manner that diminishes the 

historic character of the exterior or that damages interior features or 

spaces. 

Replacing a historic structural feature in its entirety or in part when 

it could be repaired or augmented and retained. 

[32] (a-b) The rehabilitation of the 1892 Carson Block Building in Eureka, CA, for 

its owner, the Northern California Indian Development Council, included recreating 

the missing corner turret and sensitively introducing seismic reinforcement (c) 

shown here (opposite page) in a secondary upper floor office space. Photos: Page 

& Turnbull. 

122 STRUCTURAL SYSTEMS 
REHABILITATION

STRUCTURAL SYSTEMS 

RECOMMENDED NOT RECOMMENDED 

Installing seismic or structural reinforcement, when necessary, 

in a manner that minimizes its impact on the historic fabric and 

character of the building. 

Replacing in kind or with a compatible substitute material large 

portions or entire features of the structural system that are either 

extensively damaged or deteriorated or that are missing when 

there are surviving prototypes, such as cast-iron columns, trusses, 

or masonry walls. Substitute material must be structurally sufficient, physically compatible with the rest of the system, and, 

where visible, must have the same form, design, and appearance 

as the historic feature. 

Using substitute material that does not equal the load-bearing 

capabilities of the historic material; does not convey the same 

appearance of the historic material, if it is visible; or is physically 

incompatible. 

Installing a visible or exposed structural replacement feature that 

does not match. 

Replacing to match any interior features or finishes that may 

have to be removed to gain access to make structural repairs, and 

reusing salvageable material. 

STRUCTURAL SYSTEMS 123
REHABILITATION

STRUCTURAL SYSTEMS 

RECOMMENDED NOT RECOMMENDED 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Alterations and Additions for a New Use 

Limiting any new excavations next to historic foundations to avoid 

undermining the structural stability of the building or adjacent 

historic buildings. The area next to the building foundation 

should be investigated first to ascertain potential damage to site 

features or archeological resources. 

Carrying out excavations or regrading land adjacent to a historic 

building which could cause the historic foundation to settle, shift, 

or fail, or which could destroy significant archeological resources. 

Correcting structural deficiencies needed to accommodate a new 

use in a manner that preserves the structural system and individual character-defining features. 

Making substantial changes to significant interior spaces or damaging or destroying features or finishes that are character defining to 

correct structural deficiencies. 

Designing and installing new mechanical or electrical equipment, 

when necessary, in a manner that minimizes the number and size 

of cuts or holes in structural members. 

Installing new mechanical or electrical equipment in a manner 

which reduces the load-bearing capacity of historic structural members. 

Inserting a new floor when required for the new use if it does not Inserting a new floor that damages or destroys the structural system 

negatively impact the historic character of the interior space; and or abuts window glazing and is visible from the exterior of the buildif it does not damage the structural system, does not abut window ing and, thus, negatively impacts its historic character. 

glazing, and is not visible from the exterior of the building. 

Creating an atrium, light court, or lightwell to provide natural Removing structural features to create an atrium, light court, or 

light when required for a new use only when it can be done in lightwell if it negatively impacts the historic character of the builda manner that preserves the structural system and the historic ing. 

character of the building. 

124 STRUCTURAL SYSTEMS 
REHABILITATION

MECHANICAL SYSTEMS: HEATING, AIR CONDITIONING, ELECTRICAL, AND PLUMBING 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving visible features of early 

mechanical systems that are important in defining the overall 

historic character of the building, such as radiators, vents, fans, 

grilles, and plumbing and lighting fixtures. 

Removing or substantially changing visible features of mechanical 

systems that are important in defining the overall historic character 

of the building so that, as a result, the character is diminished. 

Protecting and maintaining mechanical, plumbing, and electrical 

systems and their features through cyclical maintenance. 

Failing to protect and maintain a functioning mechanical system, 

plumbing, and electrical systems and their visible features on a 

cyclical basis so that their deterioration results. 

Improving the energy efficiency of existing mechanical systems 

to help reduce the need for a new system by installing storm 

windows, insulating attics and crawl spaces, or adding awnings, 

if appropriate. 

Evaluating the overall condition of mechanical systems to determine whether more than protection and maintenance, such as 

repairs to mechanical system components, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

mechanical system components. 

Repairing mechanical systems by augmenting or upgrading 

system components (such as installing new pipes and ducts), 

rewiring, or adding new compressors or boilers. 

Replacing a mechanical system when its components could be 

upgraded and retained. 

Replacing in kind or with a compatible substitute material those Installing a visible replacement feature of a mechanical system, if it 

extensively deteriorated or missing visible features of mechanical is important in defining the historic character of the building, that 

systems when there are surviving prototypes, such as ceiling fans, does not convey the same appearance. 

radiators, grilles, or plumbing fixtures. 

MECHANICAL SYSTEMS 125
REHABILITATION

MECHANICAL SYSTEMS: HEATING, AIR CONDITIONING, ELECTRICAL, AND PLUMBING 

RECOMMENDED NOT RECOMMENDED 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Alterations and Additions for a New Use 

Installing a new mechanical system, if required, so that it results 

in the least alteration possible to the historic building and its 

character-defining features. 

Installing a new mechanical system so that character-defining 

structural or interior features are radically changed, damaged, or 

destroyed. 

Providing adequate structural support for the new mechanical 

equipment. 

Failing to consider the weight and design of new mechanical equipment so that, as a result, historic structural members or finished 

surfaces are weakened or cracked. 

Installing new mechanical and electrical systems and ducts, 

pipes, and cables in closets, service areas, and wall cavities to 

preserve the historic character of the interior space. 

Installing systems and ducts, pipes, and cables in walls or ceilings 

in a manner that results in extensive loss or damage or otherwise 

obscures historic building materials and character-defining features. 

Concealing HVAC ductwork in finished interior spaces, when possible, by installing it in secondary spaces (such as closets, attics, 

basements, or crawl spaces) or in appropriately-located, furreddown soffits. 

Leaving HVAC ductwork exposed in most finished spaces or installing soffits in a location that will negatively impact the historic 

character of the interior or exterior of the building. 

Installing exposed ductwork in a finished space when necessary Installing exposed ductwork in a finished space when necessary to 

to protect and preserve decorative or other features (such as protect and preserve decorative or other features that is not painted, 

column capitals, pressed-metal or ornamental plaster ceilings, or is located where it will negatively impact the historic character of 

coffers, or beams) that is painted, and appropriately located so the space. 

that it will have minimal impact on the historic character of the 

space. 

Lowering ceilings, installing a dropped ceiling, or constructing Lowering ceilings, installing a dropped ceiling, or constructing sofsoffits to conceal ductwork in a finished space when this will not fits to conceal ductwork in a finished space in a manner that results 

result in extensive loss or damage to historic materials or decora­ in extensive loss or damage to historic materials or decorative and 

tive and other features, and will not change the overall character other features, and will change the overall character of the space or 

of the space or the exterior appearance of the building (i.e., the exterior appearance of the building. 

lowered ceilings or soffits visible through window glazing). 

126 MECHANICAL SYSTEMS 
REHABILITATION

MECHANICAL SYSTEMS: HEATING, AIR CONDITIONING, ELECTRICAL, AND PLUMBING 

RECOMMENDED NOT RECOMMENDED 

Installing appropriately located, exposed ductwork in historicallyunfinished interior spaces in industrial or utilitarian buildings. 

Installing a split system mechanical unit in a manner that will 

have minimal impact on the historic character of the interior and 

result in minimal loss of historic building material. 

Installing a split system mechanical unit without considering its 

impact on the historic character of the interior or the potential loss 

of historic building material. 

Installing heating or air conditioning window units only when 

the installation of any other system would result in significant 

damage or loss of historic materials or features. 

Installing mechanical equipment on the roof, when necessary, 

so that it is minimally visible to preserve the building’s historic 

character and setting. 

Installing mechanical equipment on the roof that is overly large or 

highly visible and negatively impacts the historic character of the 

building or setting. 

Placing air conditioning compressors in a location on a secondary 

elevation of the historic building that is not highly visible. 

Placing air conditioning compressors where they are highly visible 

and negatively impact the historic character of the building or 

setting. 

[34] The new ceiling 

ducts installed during 

the conversion of this 

historic office building 

into apartments are 

minimal in design and 

discretely placed above 

the windows. 

MECHANICAL SYSTEMS 127
REHABILITATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving a floor plan or interior Altering a floor plan, or interior spaces (including individual rooms), 

spaces, features, and finishes that are important in defining features, and finishes, which are important in defining the overall 

the overall historic character of the building. Significant spatial historic character of the building so that, as a result, the character 

characteristics include the size, configuration, proportion, and is diminished. 

relationship of rooms and corridors; the relationship of features to 

spaces; and the spaces themselves, such as lobbies, lodge halls, Altering the floor plan by demolishing principal walls and partitions 

entrance halls, parlors, theaters, auditoriums, gymnasiums, and for a new use. 

industrial and commercial interiors. Color, texture, and pattern 

are important characteristics of features and finishes, which can Altering or destroying significant interior spaces by inserting addiinclude such elements as columns, plaster walls and ceilings, tional floors or lofts; cutting through floors to create lightwells, light 

flooring, trim, fireplaces and mantels, paneling, light fixtures, courts, or atriums; lowering ceilings; or adding new walls or removhardware, decorative radiators, ornamental grilles and registers, ing historic walls. 

windows, doors, and transoms; plaster, paint, wallpaper and wall 

coverings, and special finishes, such as marbleizing and graining; Relocating an interior feature, such as a staircase, so that the cirand utilitarian (painted or unpainted) features, including wood, culation pattern and the historic relationship between features and 

metal, or concrete exposed columns, beams, and trusses and spaces are altered. 

exposed load-bearing brick, concrete, and wood walls. 

Installing new material that obscures or damages character-defining 

interior features or finishes. 

Removing paint, plaster, or other finishes from historically-finished 

interior surfaces to create a new appearance (e.g., removing plaster 

to expose brick walls or a brick chimney breast, stripping paint from 

wood to stain or varnish it, or removing a plaster ceiling to expose 

unfinished beams). 

Applying paint, plaster, or other coatings to surfaces that have been 

unfinished historically, thereby changing their character. 

Changing the type of finish or its color, such as painting a historically-varnished wood feature, or removing paint from a historicallypainted feature. 

128 INTERIOR SPACES, FEATURES, AND FINISHES 
REHABILITATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Retaining decorative or other character-defining features or 

finishes that typify the showroom or interior of a historic store, 

such as a pressed-metal ceiling, a beaded-board ceiling, or 

wainscoting. 

Removing decorative or other character-defining features or finishes 

that typify the showroom or interior of a historic store, such as a 

pressed-metal ceiling, a beaded-board ceiling, or wainscoting. 

Protecting and maintaining historic materials (including plaster, masonry, wood, and metals) which comprise interior spaces 

through appropriate surface treatments, such as cleaning, paint 

removal, and reapplication of protective coating systems. 

Failing to protect and maintain interior materials and finishes on a 

cyclical basis so that deterioration of interior features results. 

Protecting interior features and finishes against arson and vandal- Leaving the building unprotected and subject to vandalism before 

ism before project work begins by erecting temporary fencing or work begins, thereby allowing the interior to be damaged if it can be 

by covering broken windows and open doorways, while ensuring accessed through unprotected entrances. 

adequate ventilation, and by installing alarm systems keyed into 

local protection agencies. 

Protecting interior features (such as a staircase, mantel, flooring, 

or decorative finishes) from damage during project work by covering them with plywood, heavy canvas, or plastic sheeting. 

Failing to protect interior features and finishes when working on the 

interior. 

[35] (a) Although 

deteriorated, the 

historic school corridor, 

shown on the left, with 

its character-defining 

features, including doors 

and transoms, was 

retained and repaired as 

part of the rehabilitation 

project (b). 

INTERIOR SPACES, FEATURES, AND FINISHES 129
REHABILITATION

130

[36] The elaborate 

features and finishes 

of this historic banking 

hall in the Union Trust 

Company Building, in 

Cleveland, OH, were 

retained and repaired as 

part of its conversion into 

a food market. 

INTERIOR SPACES, FEATURES, AND FINISHES 
REHABILITATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Removing damaged or deteriorated paint and finishes only to 

the next sound layer using the gentlest method possible prior to 

repainting or refinishing using compatible paint or other coating 

systems. 

Using potentially damaging methods, such as open-flame torches or 

abrasive techniques, to remove paint or other coatings. 

Removing paint that is firmly adhered to interior surfaces. 

Using abrasive cleaning methods only on the interior of industrial Using abrasive methods anywhere but utilitarian and industrial 

or warehouse buildings with utilitarian, unplastered masonry interior spaces or when there are other methods that are less likely 

walls and where wood features are not finished, molded, beaded, to damage the surface of the material. 

or worked by hand. Low-pressure abrasive cleaning (e.g., sandblasting or other media blasting) should only be considered if test 

patches show no surface damage and after gentler methods have 

proven ineffective. 

Evaluating the overall condition of the interior materials, features, Failing to undertake adequate measures to ensure the protection of 

and finishes to determine whether more than protection and interior materials, features, and finishes. 

maintenance, such as repairs to features and finishes, will be 

necessary. 

Repairing interior features and finishes by patching, splicing, Removing materials that could be repaired or using improper repair 

consolidating, or otherwise reinforcing the materials using rec- techniques. 

ognized preservation methods. Repairs may include the limited 

replacement in kind or with a compatible substitute material of Replacing an entire interior feature (such as a staircase, mantel, or 

those extensively deteriorated or missing parts of interior features door surround) or a finish (such as a plaster) when repair of materiwhen there are surviving prototypes, such as stairs, balustrades, als and limited replacement of deteriorated or missing components 

wood paneling, columns, decorative wall finishes, and ornamental are feasible. 

pressed-metal or plaster ceilings. Repairs should be physically 

and visually compatible. 

INTERIOR SPACES, FEATURES, AND FINISHES 131
REHABILITATION

132

[38] The rehabilitation 

project retained the 

industrial character of this 

historic factory building, 

which included installation 

of a fire-rated, clear glass 

enclosure that allows the 

stairway, an important 

interior feature, to remain 

visible. 

[37] Exposed and painted 

ducts were appropriately 

installed here in a retail 

space in Denver’s historic 

Union Station after 

considering other options 

that would have impacted 

the ceiling height, or 

damaged or obscured the 

ornamental plaster crown 

molding. Photo: Heritage 

Consulting Group. 

[39] Leaving the ceiling 

structure exposed 

and installing exposed 

ductwork where it 

does not impact 

the windows, are 

appropriate treatments 

when rehabilitating an 

industrial building for 

another use. 

INTERIOR SPACES, FEATURES, AND FINISHES 
REHABILITATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire interior feature that is too deteriorated to repair (if the overall form and detailing are still evident) 

using the physical evidence as a model to reproduce the feature. 

Examples could include wainscoting, window and door surrounds, 

or stairs. If using the same kind of material is not feasible, then a 

compatible substitute material may be considered. 

Removing a character-defining interior feature that is unrepairable 

and not replacing it, or replacing it with a new feature or finish that 

does not match the historic feature. 

Using a substitute material for the replacement that does not 

convey the same appearance of the interior feature or that is physically incompatible. 

Using a substitute material for the replacement that does not 

convey the same appearance of the interior feature or that is physically incompatible. 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a new interior feature or finish when Creating an inaccurate appearance because the replacement for 

the historic feature or finish is completely missing. This could the missing feature is based upon insufficient physical or historic 

include missing walls, stairs, mantels, wood trim, and plaster, or documentation; is not a compatible design; or because the feature 

even entire rooms if the historic spaces, features, and finishes did not coexist with the feature currently on the building. 

are missing or have been destroyed by inappropriate alterations. 

The design may be an accurate restoration based on documentary Introducing a new interior feature or finish that is incompatible in 

and physical evidence, but only when the feature or finish to be size, scale, material, color, and finish. 

replaced coexisted with the features currently in the building. Or, 

it may be a new design that is compatible with the size, scale, 

material, and color of the historic building. 

Alterations and Additions for a New Use 

Installing new or additional systems required for a new use for 

the building, such as bathrooms and mechanical equipment, in 

secondary spaces to preserve the historic character of the most 

significant interior spaces. 

Subdividing primary spaces, lowering ceilings, or damaging or 

obscuring character-defining features (such as fireplaces, windows, 

or stairways) to accommodate a new use for the building. 

INTERIOR SPACES, FEATURES, AND FINISHES 133
REHABILITATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Installing new mechanical and electrical systems and ducts, Installing ducts, pipes, and cables where they will obscure characpipes, and cables in closets, service areas, and wall cavities to ter-defining features or negatively impact the historic character of 

preserve the historic character of interior spaces, features, and the interior. 

finishes. 

Creating open work areas, when required by the new use, by 

selectively removing walls only in secondary spaces, less significant upper floors, or other less-visible locations to preserve 

primary public spaces and circulation systems. 

Retaining the configuration of corridors, particularly in build- Making extensive changes to the character of significant historic 

ings with multiple floors with repetitive plans (such as office corridors by narrowing or radically shortening them, or removing 

and apartment buildings or hotels), where not only the floor plan their character-defining features. 

is character defining, but also the width and the length of the 

corridor, doorways, transoms, trim, and other features, such as 

wainscoting and glazing. 

Reusing decorative material or features that had to be removed as Discarding historic material when it can be reused to replace misspart of the rehabilitation work (including baseboards, door casing, ing or damaged features elsewhere in the building, or reusing matepaneled doors, and wainscoting) and reusing them in areas where rial in a manner that may convey a false sense of history. 

these features are missing or are too deteriorated to repair. 

Installing permanent partitions in secondary, rather than primary, spaces whenever feasible. Removable partitions or partialheight walls that do not destroy the sense of space often may be 

installed in large character-defining spaces when required by a 

new use. 

Installing partitions that abut windows and glazing or that damage 

or obscure character-defining spaces, features, or finishes. 

Enclosing a character-defining interior stairway, when required by 

code, with fire-rated glass walls or large, hold-open doors so that 

the stairway remains visible and its historic character is retained. 

Enclosing a character-defining interior stairway for safety or functional reasons in a manner that conceals it or destroys its character. 

Locating new, code-required stairways or elevators in secondary 

and service areas of the historic building. 

Making incompatible changes or damaging or destroying characterdefining spaces, features, or finishes when adding new coderequired stairways and elevators. 

134 INTERIOR SPACES, FEATURES, AND FINISHES 
REHABILITATION

[40] Not Recommended: 

Removing a finished 

ceiling and leaving the 

structure exposed in a 

historic retail space does 

not meet the Standards 

for Rehabilitation. 

[41] Not Recommended: 

Leaving fragments 

of deteriorated or 

“sculpted” plaster is not 

a compatible treatment 

for either finished or 

unfinished interior 

spaces. 

INTERIOR SPACES, FEATURES, AND FINISHES 135
REHABILITATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Creating an atrium, light court, or lightwell to provide natural Destroying or damaging character-defining interior spaces, features, 

light when required for a new use only when it can be done in a or finishes, or damaging the structural system to create an atrium, 

manner that preserves significant interior spaces, features, and light court, or lightwell. 

finishes or important exterior elevations. 

Inserting a new floor, mezzanine, or loft when required for a new Inserting a new floor, mezzanine, or loft that damages or destroys 

use if it does not damage or destroy significant interior features significant interior features or abuts window glazing and is visible 

and finishes and is not visible from the exterior of the building. from the exterior of the building, and, thus, negatively impacts its 

historic character. 

Inserting a new floor, when necessary for a new use, only in large Inserting a new floor in significant, large assembly spaces with 

assembly spaces that are secondary to another assembly space distinctive features and finishes, which negatively impacts their 

in the building; in a space that has been greatly altered; or where historic character. 

character-defining features have been lost or are too deteriorated 

to repair. 

Installing exposed ductwork in a finished space when necessary Installing exposed ductwork in a finished space when necessary to 

to protect and preserve decorative or other features (such as protect and preserve decorative or other features that is not painted, 

column capitals, ornamental plaster or pressed-metal ceilings, or is located where it will negatively impact the historic character of 

coffers, or beams) that is designed, painted, and appropriately the space. 

located so that it will have minimal impact on the historic character of the space. 

Lowering ceilings, installing a dropped ceiling, or constructing Lowering ceilings, installing a dropped ceiling, or constructing sofsoffits to conceal ductwork in a finished space when they will not fits to conceal ductwork in a finished space in a manner that results 

result in extensive loss or damage to historic materials or decora­ in extensive loss or damage to historic materials or decorative and 

tive and other features, and will not change the overall character other features, and will change the overall character of the space or 

of the space or the exterior appearance of the building (i.e., the exterior appearance of the building. 

lowered ceilings or soffits visible through window glazing). 

Installing a split system mechanical unit in a manner that will 

have minimal impact on the historic character of the interior and 

will result in minimal loss of historic building material. 

Installing a split system mechanical unit without considering its 

impact on the historic character of the interior or the potential loss 

of historic building material. 

136 INTERIOR SPACES, FEATURES, AND FINISHES 
REHABILITATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving features of the building site Removing or substantially changing buildings and their features 

that are important in defining its overall historic character. Site or site features which are important in defining the overall historic 

features may include walls, fences, or steps; circulation systems, character of the property so that, as a result, the character is diminsuch as walks, paths or roads; vegetation, such as trees, shrubs, ished. 

grass, orchards, hedges, windbreaks, or gardens; landforms, such 

as hills, terracing, or berms; furnishings and fixtures, such as 

light posts or benches; decorative elements, such as sculpture, 

statuary, or monuments; water features, including fountains, 

streams, pools, lakes, or irrigation ditches; and subsurface archeological resources, other cultural or religious features, or burial 

grounds which are also important to the site. 

[42] This garden is an 

important characterdefining landscape 

feature on this college 

campus. 

BUILDING SITE 137
REHABILITATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Retaining the historic relationship between buildings and the 

landscape. 

Removing or relocating buildings or landscape features, thereby 

destroying the historic relationship between buildings and the landscape. 

Removing or relocating buildings on a site or in a complex of related 

historic structures (such as a mill complex or farm), thereby diminishing the historic character of the site or complex. 

Moving buildings onto the site, thereby creating an inaccurate historic appearance. 

Changing the grade level of the site if it diminishes its historic 

character. For example, lowering the grade adjacent to a building 

to maximize use of a basement, which would change the historic 

appearance of the building and its relation to the site. 

Protecting and maintaining buildings and site features by providing proper drainage to ensure that water does not erode foundation walls, drain toward the building, or damage or erode the 

landscape. 

Failing to ensure that site drainage is adequate so that buildings 

and site features are damaged or destroyed; or, alternatively, changing the site grading so that water does not drain properly. 

Correcting any existing irrigation that may be wetting the building excessively. Neglecting to correct any existing irrigation that may be wetting the 

building excessively. 

Minimizing disturbance of the terrain around buildings or else- Using heavy machinery or equipment in areas where it may disturb 

where on the site, thereby reducing the possibility of destroy- or damage important landscape features, archeological resources, 

ing or damaging important landscape features, archeological other cultural or religious features, or burial grounds. 

resources, other cultural or religious features, or burial grounds. 

Surveying and documenting areas where the terrain will be Failing to survey the building site prior to beginning work, which 

altered to determine the potential impact to important landscape may result in damage or loss of important landscape features, 

features, archeological resources, other cultural or religious fea­ archeological resources, other cultural or religious features, or burial 

tures, or burial grounds. grounds. 

138 BUILDING SITE 
REHABILITATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Protecting (e.g., preserving in place) important site features, 

archeological resources, other cultural or religious features, or 

burial grounds. 

Leaving known site features or archeological material unprotected so 

that it is damaged during rehabilitation work. 

Planning and carrying out any necessary investigation before 

rehabilitation begins, using professional archeologists and methods, when preservation in place is not feasible. 

Allowing unqualified personnel to perform data recovery on archeological resources, which can result in damage or loss of important 

archeological material 

Preserving important landscape features through regularly-scheduled maintenance of historic plant material. Allowing important landscape features or archeological resources to 

be lost, damaged, or to deteriorate due to inadequate protection or 

lack of maintenance 

Protecting the building site and landscape features against arson Leaving the property unprotected and subject to vandalism before 

and vandalism before rehabilitation work begins by erecting tem­ work begins so that the building site and landscape features, 

porary fencing and by installing alarm systems keyed into local archeological resources, other cultural or religious features, or burial 

protection agencies. grounds can be damaged or destroyed. 

Removing or destroying features from the site, such as fencing, 

paths or walkways, masonry balustrades, or plant material. 

Installing protective fencing, bollards, and stanchions on a build- Installing protective fencing, bollards, and stanchions on a building 

ing site, when necessary for security, that are as unobtrusive as site, when necessary for security, without taking into consideration 

possible. their location and visibility so that they negatively impact the historic character of the site. 

Providing continued protection and maintenance of buildings 

and landscape features on the site through appropriate grounds 

and landscape management. 

Failing to protect and maintain materials and features from the 

restoration period on a cyclical basis so that deterioration of the site 

results. 

Protecting buildings and landscape features when working on the 

site. 

Failing to protect building and landscape features during work on 

the site or failing to repair damaged or deteriorated site features. 

BUILDING SITE 139
REHABILITATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Evaluating the overall condition of materials and features to 

determine whether more than protection and maintenance, such 

as repairs to site features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

the site. 

Repairing historic site features which have been damaged, are 

deteriorated, or have missing components order reestablish the 

whole feature and to ensure retention of the integrity of the 

historic materials. Repairs may include limited replacement in 

kind or with a compatible substitute material of those extensively 

deteriorated or missing parts of site features when there are 

surviving prototypes, such as paving, railings, or individual plants 

within a group (e.g., a hedge). Repairs should be physically and 

visually compatible. 

Removing materials and features that could be repaired or using 

improper repair techniques. 

Replacing an entire feature of the site (such as a fence, walkway, or 

drive) when repair of materials and limited replacement of deteriorated or missing components are feasible. 

[43] The industrial 

character of the site 

was retained when 

this brewery complex 

was rehabilitated for 

residential use. 

[44] Not Recommended: (a-b) The historic character of this plantation house 

(marked in blue on plan on opposite page) and its site was diminished and 

adversely impacted when multiple new buildings like this (#3 on plan) were 

constructed on the property (c). 

140 BUILDING SITE 
REHABILITATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire feature of the site that is too deterio- Removing a character-defining feature of the site that is unrepairrated to repair (if the overall form and detailing are still evident) able and not replacing it, or replacing it with a new feature that does 

using the physical evidence as a model to reproduce the feature. not match. 

Examples could include a walkway or a fountain, a land form, or 

plant material. If using the same kind of material is not feasible, Using a substitute material for the replacement that does not convey 

then a compatible substitute material may be considered. the same appearance of the surviving site feature or that is physically or ecologically incompatible. 

Adding conjectural landscape features to the site (such as period 

reproduction light fixtures, fences, fountains, or vegetation) that are 

historically inappropriate, thereby creating an inaccurate appearance 

of the site. 

BUILDING SITE 141
REHABILITATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

[45] Undertaking a 

survey to document 

archeological resources 

may be considered in 

some rehabilitation 

projects when a new 

exterior addition is 

planned. 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a new feature on a site when the his- Creating an inaccurate appearance because the replacement for 

toric feature is completely missing. This could include missing the missing feature is based upon insufficient physical or historic 

outbuildings, terraces, drives, foundation plantings, specimen documentation, is not a compatible design, or because the feature 

trees, and gardens. The design may be an accurate restoration did not coexist with the features currently on the site. 

based on documentary and physical evidence, but only when the 

feature to be replaced coexisted with the features currently on Introducing a new feature, including plant material, that is visually 

the site. Or, it may be a new design that is compatible with the incompatible with the site or that alters or destroys the historic site 

historic character of the building and site. patterns or use. 

Alterations and Additions for a New Use 

Designing new onsite features (such as parking areas, access Locating parking areas directly adjacent to historic buildings where 

ramps, or lighting), when required by a new use, so that they vehicles may cause damage to buildings or landscape features or 

are as unobtrusive as possible, retain the historic relationship when they negatively impact the historic character of the building 

between the building or buildings and the landscape, and are site if landscape features and plant materials are removed. 

compatible with the historic character of the property. 

Designing new exterior additions to historic buildings or adjacent Introducing new construction on the building site which is visunew construction that are compatible with the historic character ally incompatible in terms of size, scale, design, material, or color, 

of the site and preserves the historic relationship between the which destroys historic relationships on the site, or which dambuilding or buildings and the landscape. ages or destroys important landscape features, such as replacing a 

lawn with paved parking areas or removing mature trees to widen a 

driveway. 

Removing non-significant buildings, additions, or site features 

which detract from the historic character of the site. 

Removing a historic building in a complex of buildings or removing a 

building feature or a landscape feature which is important in defining the historic character of the site. 

Locating an irrigation system needed for a new or continuing use 

of the site where it will not cause damage to historic buildings. 

Locating an irrigation system needed for a new or continuing use of 

the site where it will damage historic buildings. 

142 BUILDING SITE 
REHABILITATION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving building and landscape Removing or substantially changing those building and landscape 

features that are important in defining the overall historic features in the setting which are important in defining the historic 

character of the setting. Such features can include circulation character so that, as a result, the character is diminished. 

systems, such as roads and streets; furnishings and fixtures, 

such as light posts or benches; vegetation, gardens and yards; 

adjacent open space, such as fields, parks, commons, or woodlands; and important views or visual relationships. 

[46] The varied size, shapes, and architectural styles of these historic 

buildings are unique to this street in Christiansted, St. Croix, USVI, and 

should be retained in a rehabilitation project. 

[47] Original paving stones contribute to the character of the historic 

setting and distinguish this block from other streets in the district. 

SETTING (DISTRICT / NEIGHBORHOOD) 143
REHABILITATION

SETTING (DISTRICT / NEIGHBORHOOD) 

[48] Old police and fire call boxes, 

which are distinctive features in this 

historic district, have been retained, 

and now showcase work by local 

artists. 

[49] Low stone walls are characterdefining features in this hilly, 

early-20th-century residential 

neighborhood. 

RECOMMENDED NOT RECOMMENDED 

Retaining the historic relationship between buildings and Altering the relationship between the buildings and landscape fealandscape features in the setting. For example, preserving the tures in the setting by widening existing streets, changing landscape 

relationship between a town common or urban plaza and the materials, or locating new streets or parking areas where they may 

adjacent houses, municipal buildings, roads, and landscape and negatively impact the historic character of the setting. 

streetscape features. 

Removing or relocating buildings or landscape features, thereby 

destroying the historic relationship between buildings and the landscape in the setting. 

144 SETTING (DISTRICT / NEIGHBORHOOD) 
REHABILITATION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

Protecting and maintaining historic features in the setting Failing to protect and maintain materials in the setting on a cyclithrough regularly-scheduled maintenance and grounds and land- cal basis so that deterioration of buildings and landscape features 

scape management. results. 

Stripping or removing historic features from buildings or the setting, 

such as a porch, fencing, walkways, or plant material. 

Installing protective fencing, bollards, and stanchions in the Installing protective fencing, bollards, and stanchions in the setting, 

setting, when necessary for security, that are as unobtrusive as when necessary for security, without taking into consideration their 

possible. location and visibility so that they negatively impact the historic 

character of the setting. 

Protecting buildings and landscape features when undertaking 

work in the setting. 

Failing to protect buildings and landscape features during work in 

the setting. 

Evaluating the overall condition of materials and features to Failing to undertake adequate measures to ensure the protection of 

determine whether more than protection and maintenance, materials and features in the setting. 

such as repairs to materials and features in the setting, will be 

necessary. 

Repairing features in the setting by reinforcing the historic 

materials. Repairs may include the replacement in kind or with a 

compatible substitute material of those extensively deteriorated 

or missing parts of setting features when there are surviving prototypes, such as fencing, paving materials, trees, and hedgerows. 

Repairs should be physically and visually compatible. 

Failing to repair and reinforce damaged or deteriorated historic 

materials and features in the setting. 

Removing material that could be repaired or using improper repair 

techniques. 

Replacing an entire feature of the building or landscape in the 

setting when repair of materials and limited replacement of deteriorated or missing components are feasible. 

SETTING (DISTRICT / NEIGHBORHOOD) 145
REHABILITATION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire building or landscape feature in Removing a character-defining feature of the building or landscape 

the setting that is too deteriorated to repair (if the overall form from the setting that is unrepairable and not replacing it or replacand detailing are still evident) using the physical evidence as a ing it with a new feature that does not match. 

model to reproduce the feature. If using the same kind of material is not feasible, then a compatible substitute material may be Using a substitute material for the replacement that does not convey 

considered. the same appearance of the surviving building or landscape feature 

in the setting or that is physically or ecologically incompatible. 

The following work is highlighted to indicate that it is specific to Rehabilitation projects and should only be considered after the preservation concerns have 

been addressed. 

Designing the Replacement for Missing Historic Features 

Designing and installing a new feature of the building or landscape in the setting when the historic feature is completely 

missing. This could include missing steps, streetlights, terraces, 

trees, and fences. The design may be an accurate restoration 

based on documentary and physical evidence, but only when the 

feature to be replaced coexisted with the features currently in 

the setting. Or, it may be a new design that is compatible with 

the historic character of the setting. 

Creating an inaccurate appearance because the replacement for 

the missing feature is based upon insufficient physical or historic 

documentation; is not a compatible design, or because the feature 

did not coexist with the features currently in the setting. 

Introducing a new building or landscape feature that is visually or 

otherwise incompatible with the setting’s historic character (e.g., 

replacing low metal fencing with a high wood fence). 

Alterations and Additions for a New Use 

Designing new features (such as parking areas, access ramps, 

or lighting), when required by a new use, so that they are as 

unobtrusive as possible, retain the historic relationships between 

buildings and the landscape in the setting, and are compatible 

with the historic character of the setting. 

Locating parking areas directly adjacent to historic buildings where 

vehicles may cause damage to buildings or landscape features or 

when they negatively impact the historic character of the setting if 

landscape features and plant materials are removed. 

Designing new exterior additions to historic buildings or adjacent 

new construction that are compatible with the historic character 

of the setting that preserve the historic relationship between the 

buildings and the landscape. 

Introducing new construction into historic districts which is visually 

incompatible or that destroys historic relationships within the setting, or which damages or destroys important landscape features. 

Removing non-significant buildings, additions, or landscape features which detract from the historic character of the setting. Removing a historic building, a building feature, or landscape 

feature which is important in defining the historic character of the 

setting. 

146 SETTING (DISTRICT / NEIGHBORHOOD) 
REHABILITATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Sensitive solutions to meeting accessibility and life-safety code requirements are an important part of protecting the historic character of the building and 

site. Thus, work that must be done to meet use-specific code requirements should be considered early in planning a Rehabilitation of a historic building 

for a new use. Because code mandates are directly related to occupancy, some uses require less change than others and, thus, may be more appropriate for a 

historic building. Early coordination with code enforcement authorities can reduce the impact of alterations necessary to comply with current codes. 

ACCESSIBILITY 

Identifying the historic building’s character-defining exterior 

features, interior spaces, features, and finishes, and features of 

the site and setting which may be affected by accessibility coderequired work. 

Undertaking accessibility code-required alterations before identifying those exterior features, interior spaces, features, and finishes, 

and features of the site and setting which are character defining 

and, therefore, must be preserved. 

Complying with barrier-free access requirements in such a 

manner that the historic building’s character-defining exterior features, interior spaces, features, and finishes, and features of the 

site and setting are preserved or impacted as little as possible. 

Altering, damaging, or destroying character-defining exterior features, interior spaces, features, and finishes, or features of the site 

and setting while making modifications to a building, its site, or 

setting to comply with accessibility requirements. 

[50] This kitchen in 

a historic apartment 

complex was 

rehabilitated to 

meet accessibility 

requirements. 

[51] A new interior 

access ramp with a 

simple metal railing is 

compatible with the 

character of this midcentury-modern building. 

CODE-REQUIRED WORK | ACCESSIBILITY 147
REHABILITATION

 

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Working with specialists in accessibility and historic preservation 

to determine the most sensitive solutions to comply with access 

requirements in a historic building, its site, or setting. 

Making changes to historic buildings, their sites, or setting without 

first consulting with specialists in accessibility and historic preservation to determine the most appropriate solutions to comply with 

accessibility requirements. 

Providing barrier-free access that promotes independence for the 

user while preserving significant historic features. 

Making modifications for accessibility that do not provide independent, safe access while preserving historic features. 

Finding solutions to meet accessibility requirements that minimize the impact of any necessary alteration on the historic building, its site, and setting, such as compatible ramps, paths, and 

lifts. 

Making modifications for accessibility without considering the 

impact on the historic building, its site, and setting. 

[52] The access ramp 

blends in with the 

stone façade of the 

First National Bank in 

Stephenville, TX, and is 

appropriately located on 

the side where it is does 

not impact the historic 

character of the building. 

Photo: Nancy McCoy, 

QuimbyMcCoy 

Preservation 

Architecture, LLP. 

[54] The gently-sloped path in a historic park in 

Kansas City, MO, which accesses the memorial below, 

includes a rest area part way up the hill. 

Photo: STRATA Architecture + Preservation. 

[53] This entrance ramp (right) is compatible with the 

historic character of this commercial building. 

148 CODE-REQUIRED WORK | ACCESSIBILITY 
REHABILITATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Using relevant sections of existing codes regarding accessibility for historic buildings that provide alternative means of code 

compliance when code-required work would otherwise negatively 

impact the historic character of the property. 

Minimizing the impact of accessibility ramps by installing them 

on secondary elevations when it does not compromise accessibility or by screening them with plantings. 

Installing elevators, lifts, or incompatible ramps at a primary 

entrance, or relocating primary entrances to secondary locations to 

provide access without investigating other options or locations. 

Adding a gradual slope or grade to the sidewalk, if appropriate, 

to access the entrance rather than installing a ramp that would 

be more intrusive to the historic character of the building and the 

district. 

Adding an exterior stair or elevator tower that is compatible 

with the historic character of the building in a minimally-visible 

location only when it is not possible to accommodate it on the 

interior without resulting in the loss of significant historic spaces, 

features, or finishes. 

Installing a lift as inconspicuously as possible when it is necessary to locate it on a primary elevation of the historic building. 

Installing lifts or elevators on the interior in secondary or less 

significant spaces where feasible. 

Installing lifts or elevators on the interior in primary spaces which 

will negatively impact the historic character of the space. 

[55] The lift is compatible with the 

industrial character of this former 

warehouse. 

CODE-REQUIRED WORK | ACCESSIBILITY 149
REHABILITATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

LIFE SAFETY 

Identifying the historic building’s character-defining exterior Undertaking life-safety code-required alterations before identifying 

features, interior spaces, features, and finishes, and features of those exterior features, interior spaces, features, and finishes, and 

the site and setting which may be affected by life-safety code- features of the site and setting which are character defining and, 

required work. therefore, must be preserved. 

Complying with life-safety codes (including requirements for Altering, damaging, or destroying character-defining exterior feaimpact-resistant glazing, security, and seismic retrofit) in such a tures, interior spaces, features, and finishes, or features of the site 

manner that the historic building’s character-defining exterior fea­ and setting while making modifications to a building, its site, or 

tures, interior spaces, features, and finishes, and features of the setting to comply with life-safety code requirements. 

site and setting are preserved or impacted as little as possible. 

Removing building materials only after testing has been conducted to identify hazardous materials, and using only the least 

damaging abatement methods. 

Removing building materials without testing first to identify the 

hazardous materials, or using potentially damaging methods of 

abatement. 

Providing workers with appropriate personal equipment for protection from hazards on the worksite. Removing hazardous or toxic materials without regard for workers’ health and safety or environmentally-sensitive disposal of the 

materials. 

Working with code officials and historic preservation specialists Making life-safety code-required changes to the building without 

to investigate systems, methods, or devices to make the build- consulting code officials and historic preservation specialists, with 

ing compliant with life-safety codes to ensure that necessary the result that alterations negatively impact the historic character of 

alterations will be compatible with the historic character of the the building. 

building. 

Using relevant sections of existing codes regarding life safety for 

historic buildings that provide alternative means of code compliance when code-required work would otherwise negatively impact 

the historic character of the building. 

[56 a-b] In order to continue in its historic use, the 

door openings of this 1916 Colonial Revival-style fire 

station had to be widened to accommodate the larger 

size of modern fire trucks. Although this resulted 

in some change to the arched door surrounds, it is 

minimal and does not negatively impact the historic 

character of the building. (a) Above, before; Photo: 

Fire and Emergency Medical Services Department 

(FEMS), Washington, D.C.; below, after. 

150 CODE-REQUIRED WORK | LIFE SAFETY 
REHABILITATION

[57] Workers wear 

protective clothing while 

removing lead paint from 

metal features. 

[59] (a-b) The decorative concrete balcony railings on this 1960s building did 

not meet life-safety code requirements. They were replaced with new glass 

railings with a fritted glass pattern matching the original design—a creative 

solution that satisfies codes, while preserving the historic appearance of the 

building when viewed from the street (c-d). Photos: (a, b, d) ERA Architects, Inc.; 

(c) Nathan Cyprys, photographer. 

CODE-REQUIRED WORK | LIFE SAFETY 151
REHABILITATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Upgrading historic stairways and elevators to meet life-safety 

codes so that they are not damaged or otherwise negatively 

impacted. 

Damaging or making inappropriate alterations to historic stairways 

and elevators or to adjacent features, spaces, or finishes in the 

process of doing work to meet code requirements. 

Installing sensitively-designed fire-suppression systems, such as 

sprinklers, so that historic features and finishes are preserved. 

Covering character-defining wood features with fire-retardant 

sheathing, which results in altering their appearance. 

Applying fire-retardant coatings when appropriate, such as intumescent paint, to protect steel structural systems. Using fire-retardant coatings if they will damage or obscure character-defining features. 

Adding a new stairway or elevator to meet life-safety code 

requirements in a manner that preserves adjacent characterdefining features and spaces. 

Altering, damaging, or destroying character-defining spaces, 

features, or finishes when adding a new code-required stairway or 

elevator. 

Using existing openings on secondary or less-visible elevations or, 

if necessary, creating new openings on secondary or less-visible 

elevations to accommodate second egress requirements. 

Using a primary or other highly-visible elevation to accommodate 

second egress requirements without investigating other options or 

locations. 

Placing a code-required stairway or elevator that cannot be 

accommodated within the historic building in a new exterior addition located on a secondary or minimally-visible elevation. 

Constructing a new addition to accommodate code-required stairs 

or an elevator on character-defining elevations or where it will 

obscure, damage, or destroy character-defining features of the 

building, its site, or setting. 

Designing a new exterior stairway or elevator tower addition that 

is compatible with the historic character of the building. 

[58] Fire doors that 

retract into the walls 

have been installed here 

(not visible in photo) 

preserve the historic 

character of this corridor. 

152 CODE-REQUIRED WORK | LIFE SAFETY 
REHABILITATION

RESILIENCE TO NATURAL HAZARDS 

RECOMMENDED NOT RECOMMENDED 

Resilience to natural hazards should be addressed as part of the treatment Rehabilitation. A historic building may have existing characteristics or features 

that help address or minimize the impacts of natural hazards. These should be used to best advantage and should be taken into consideration early in the 

planning stages of a rehabilitation project before proposing any new treatments. When new adaptive treatments are needed they should be carried out in a 

manner that will have the least impact on the historic character of the building, its site, and setting. . 

Identifying the vulnerabilities of the historic property to the Failing to identify and periodically reevaluate the potential vulnerimpacts of natural hazards (such as wildfires, hurricanes, or ability of the building, its site, and setting to the impacts of natural 

tornadoes) using the most current climate information and data hazards. 

available. 

Assessing the potential impacts of known vulnerabilities on 

character-defining features of the building, its site, and setting; 

and reevaluating and reassessing potential impacts on a regular 

basis. 

Documenting the property and character-defining features as a 

record and guide for future repair work, should it be necessary, 

and storing the documentation in a weatherproof location. 

Failing to document the historic property and its character-defining 

features with the result that such information is not available in the 

future to guide repair or reconstruction work, should it be necessary. 

Ensuring that historic resources inventories and maps are accurate, up to date, and accessible in times of emergency. 

Maintaining the building, its site, and setting in good repair, and 

regularly monitoring character-defining features. 

Failing to regularly monitor and maintain the property and the 

building systems in good repair. 

Using and maintaining existing characteristics and features of the Allowing loss, damage, or destruction to occur to the historic buildhistoric building, its site, setting, and larger environment (such ing, its site, or setting by failing to evaluate potential future impacts 

as shutters for storm protection or a site wall that keeps out flood of natural hazards or to plan and implement adaptive measures, if 

waters) that may help to avoid or minimize the impacts of natural necessary to address possible threats. 

hazards 

Undertaking work to prevent or minimize the loss, damage, or Carrying out adaptive measures intended to address the impacts 

destruction of the historic property while retaining and preserving of natural hazards that are unnecessarily invasive or will otherwise 

significant features and the overall historic character of the build- adversely impact the historic character of the building, its site, or 

ing, its site, and setting. setting. 

RESILIENCE TO NATURAL HAZARDS 153
REHABILITATION

154

[60] In some instances, it may be necessary to elevate a historic building located in a floodplain to protect it. But 

this treatment is appropriate only if elevating the building will retain its historic character, including its relationship 

to the site, and its new height will be compatible with surrounding buildings if in a historic district. The house on the 

right, which has been raised only slightly, has retained its historic character. The house on the left has been raised 

several feet higher, resulting in a greater impact on the historic character of the house and the district. 

RESILIENCE TO NATURAL HAZARDS 
REHABILITATION

RESILIENCE TO NATURAL HAZARDS 

RECOMMENDED NOT RECOMMENDED 

Ensuring that, when planning work to adapt for natural hazards, 

all feasible alternatives are considered, and that the options 

requiring the least alteration are considered first. 

Implementing local and regional traditions (such as elevating 

residential buildings at risk of flooding or reducing flammable 

vegetation around structures in fire-prone areas) for adapting 

buildings and sites in response to specific natural hazards, when 

appropriate. Such traditional methods may be appropriate if they 

are compatible with the historic character of the building, its site, 

and setting. 

Implementing a treatment traditionally used in another region or 

one typically used for a different property type or architectural style 

which is not compatible with the historic character of the property. 

Using special exemptions and variances when adaptive treatments to protect buildings from known hazards would otherwise 

negatively impact the historic character of the building, its site, 

and setting. 

Considering adaptive options, whenever possible, that would 

protect multiple historic resources, if the treatment can be implemented without negatively impacting the historic character of 

the district, or archeological resources, other cultural or religious 

features, or burial grounds. 

Sustainability 

Sustainability is usually a very important and integral part of the 

treatment Rehabilitation. Existing energy-efficient features should 

be taken into consideration early in the planning stages of a rehabilitation project before proposing any energy improvements. There are 

numerous treatments that may be used to upgrade a historic building to help it operate more efficiently while retaining its character. 

The topic of sustainability is addressed in detail in The Secretary of 

the Interior’s Standards for Rehabilitation & Illustrated Guidelines on Sustainability for Rehabilitating Historic Buildings. 

RESILIENCE TO NATURAL HAZARDS 155
REHABILITATION

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND 

RELATED NEW CONSTRUCTION 

RECOMMENDED NOT RECOMMENDED 

New Additions 

Placing functions and services required for a new use (including 

elevators and stairways) in secondary or non-character-defining 

interior spaces of the historic building rather than constructing a 

new addition. 

Expanding the size of the historic building by constructing a new 

addition when requirements for the new use could be met by altering non-character-defining interior spaces. 

Constructing a new addition on a secondary or non-characterdefining elevation and limiting its size and scale in relationship to 

the historic building. 

Constructing a new addition on or adjacent to a primary elevation 

of the building which negatively impacts the building’s historic 

character. 

Constructing a new addition that results in the least possible loss 

of historic materials so that character-defining features are not 

obscured, damaged, or destroyed. 

Attaching a new addition in a manner that obscures, damages, or 

destroys character-defining features of the historic building. 

Designing a new addition that is compatible with the historic 

building. 

Designing a new addition that is significantly different and, thus, 

incompatible with the historic building. 

Ensuring that the addition is subordinate and secondary to the 

historic building and is compatible in massing, scale, materials, 

relationship of solids to voids, and color. 

Constructing a new addition that is as large as or larger than the 

historic building, which visually overwhelms it (i.e., results in the 

diminution or loss of its historic character). 

156 NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND RELATED NEW CONSTRUCTION 
REHABILITATION

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND 

RELATED NEW CONSTRUCTION 

RECOMMENDED NOT RECOMMENDED 

Using the same forms, materials, and color range of the historic 

building in a manner that does not duplicate it, but distinguishes 

the addition from the original building. 

Duplicating the exact form, material, style, and detailing of the 

historic building in a new addition so that the new work appears to 

be historic. 

Basing the alignment, rhythm, and size of the window and door 

openings of the new addition on those of the historic building. 

Incorporating a simple, recessed, small-scale hyphen, or connection, to physically and visually separate the addition from the 

historic building. 

Distinguishing the addition from the original building by setting it 

back from the wall plane of the historic building. 

[61 a-b] The materials, 

design, and location at 

the back of the historic 

house are important 

factors in making this a 

compatible new addition. 

Photos: © Maxwell 

MacKenzie. 

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND RELATED NEW CONSTRUCTION 157
REHABILITATION

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND 

RELATED NEW CONSTRUCTION 

RECOMMENDED NOT RECOMMENDED 

Ensuring that the addition is stylistically appropriate for the historic building type (e.g., whether it is residential or institutional). 

Considering the design for a new addition in terms of its relationship to the historic building as well as the historic district, 

neighborhood, and setting. 

[62] The stair tower 

at the rear of this 

commercial building 

is a compatible new 

addition. 

158 NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND RELATED NEW CONSTRUCTION 
REHABILITATION

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND 

RELATED NEW CONSTRUCTION 

RECOMMENDED NOT RECOMMENDED 

Rooftop Additions 

Designing a compatible rooftop addition for a multi-story building, when required for a new use, that is set back at least one full 

bay from the primary and other highly-visible elevations and that 

is inconspicuous when viewed from surrounding streets. 

Constructing a rooftop addition that is highly visible, which negatively impacts the character of the historic building, its site, setting, 

or district. 

[ 63] (a) A mockup 

should be erected 

to demonstrate the 

visibility of a proposed 

rooftop addition and its 

potential impact on the 

historic building. Based 

on review of this mockup 

(orange marker), it was 

determined that the 

rooftop addition would 

meet the Standards 

(b). The addition is 

unobtrusive and blends 

in with the building 

behind it. 

New addition 

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND RELATED NEW CONSTRUCTION 159
REHABILITATION

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND 

RELATED NEW CONSTRUCTION 

RECOMMENDED NOT RECOMMENDED 

Limiting a rooftop addition to one story in height to minimize its 

visibility and its impact on the historic character of the building. 

Constructing a highly-visible, multi-story rooftop addition that alters 

the building’s historic character. 

Constructing a rooftop addition on low-rise, one- to three-story historic buildings that is highly visible, overwhelms the building, and 

negatively impacts the historic district. 

Constructing a rooftop addition with amenities (such as a raised 

pool deck with plantings, HVAC equipment, or screening) that is 

highly visible and negatively impacts the historic character of the 

building. 

[64] Not Recommended: 

It is generally not appropriate to 

construct a rooftop addition on a 

low-rise, two- to three-story building 

such as this, because it negatively 

affects its historic character. 

160 NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND RELATED NEW CONSTRUCTION 
REHABILITATION

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND 

RELATED NEW CONSTRUCTION 

RECOMMENDED NOT RECOMMENDED [65] (a) This (far left) 

Related New Construction 

Adding a new building to a historic site or property only if the 

requirements for a new or continuing use cannot be accommodated within the existing structure or structures. 

Adding a new building to a historic site or property when the project 

requirements could be accommodated within the existing structure 

or structures. 

Locating new construction far enough away from the historic 

building, when possible, where it will be minimally visible and 

will not negatively affect the building’s character, the site, or 

setting. 

Placing new construction too close to the historic building so that it 

negatively impacts the building’s character, the site, or setting. 

is a compatible new 

outbuilding constructed 

on the site of a historic 

plantation house (b). 

Although traditional in 

design, it is built of wood 

to differentiate it from the 

historic house (which is 

scored stucco) located at 

the back of the site so as 

not to impact the historic 

house, and minimally 

visible from the public 

right-of-way (c). 

new 

addition 

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND RELATED NEW CONSTRUCTION 161
REHABILITATION

NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND 

RELATED NEW CONSTRUCTION 

RECOMMENDED NOT RECOMMENDED 

Designing new construction on a historic site or in a historic 

setting that it is compatible but differentiated from the historic 

building or buildings. 

Replicating the features of the historic building when designing a 

new building, with the result that it may be confused as historic or 

original to the site or setting. 

Considering the design for related new construction in terms of 

its relationship to the historic building as well as the historic 

district and setting. 

Ensuring that new construction is secondary to the historic building and does not detract from its significance. Adding new construction that results in the diminution or loss of 

the historic character of the building, including its design, materials, location, or setting. 

Constructing a new building on a historic property or on an adjacent 

site that is much larger than the historic building. 

Designing new buildings or groups of buildings to meet a new use 

that are not compatible in scale or design with the character of 

the historic building and the site, such as apartments on a historic 

school property that are too residential in appearance. 

Using site features or land formations, such as trees or sloping 

terrain, to help minimize the new construction and its impact on 

the historic building and property. 

Designing an addition to a historic building in a densely-built 

location (such as a downtown commercial district) to appear as 

a separate building or infill, rather than as an addition. In such 

a setting, the addition or the infill structure must be compatible 

with the size and scale of the historic building and surrounding 

buildings—usually the front elevation of the new building should 

be in the same plane (i.e., not set back from the historic building). This approach may also provide the opportunity for a larger 

addition or infill when the façade can be broken up into smaller 

elements that are consistent with the scale of the historic building and surrounding buildings. 

162 NEW EXTERIOR ADDITIONS TO HISTORIC BUILDINGS AND RELATED NEW CONSTRUCTION 
RESTORATION 

163

RESTORATION

STANDARDS FOR RESTORATION &
 

GUIDELINES FOR RESTORING HISTORIC BUILDINGS
 

Restoration

Restoration is defined as the act or process of accurately depicting 

the form, features, and character of a property as it appeared at a 

particular period of time by means of the removal of features from 

other periods in its history and reconstruction of missing features 

from the restoration period. The limited and sensitive upgrading 

of mechanical, electrical, and plumbing systems and other coderequired work to make properties functional is appropriate within 

a restoration project. 
164

RESTORATION

Standards for Restoration 

1. 	 A property will be used as it was historically or be given a new use that interprets the 

property and its restoration period. 

2. 	 Materials and features from the restoration period will be retained and preserved. The 

removal of materials or alteration of features, spaces and spatial relationships that characterize the period will not be undertaken. 

3. 	 Each property will be recognized as a physical record of its time, place and use. Work 

needed to stabilize, consolidate and conserve materials and features from the restoration 

period will be physically and visually compatible, identifiable upon close inspection and 

properly documented for future research. 

4. 	 Materials, features, spaces and finishes that characterize other historical periods will be 

documented prior to their alteration or removal. 

5. 	 Distinctive materials, features, finishes and construction techniques or examples of 

craftsmanship that characterize the restoration period will be preserved. 

6. 	 Deteriorated features from the restoration period will be repaired rather than replaced. 

Where the severity of deterioration requires replacement of a distinctive feature, the new 

feature will match the old in design, color, texture and, where possible, materials. 

7.	 Replacement of missing features from the restoration period will be substantiated by 

documentary and physical evidence. A false sense of history will not be created by adding 

conjectural features, features from other properties, or by combining features that never 

existed together historically. 

8. 	 Chemical or physical treatments, if appropriate, will be undertaken using the gentlest 

means possible. Treatments that cause damage to historic materials will not be used. 

9. 	 Archeological resources affected by a project will be protected and preserved in place. If 

such resources must be disturbed, mitigation measures will be undertaken. 

10. Designs that were never executed historically will not be constructed. 
165

RESTORATION

GUIDELINES FOR RESTORING HISTORIC BUILDINGS
 

INTRODUCTION 

Restoration is the treatment that should be followed when the 

expressed goal of the project is to make the building appear as it 

did at a particular—and at its most significant—time in its history. The guidance provided by the Standards for Restoration and 

Guidelines for Restoring Historic Buildings is to first identify the 

materials and features from the restoration period. After these materials and features have been identified, they should be maintained, 

protected, repaired, and replaced, when necessary. Unlike the other 

treatments in which most, if not all, of the historic elements are 

retained, restoration will likely include the removal of features from 

other periods. Missing features from the restoration period should be 

replaced, based on physical or historic documentation, with either 

the same or compatible substitute materials. Only those designs that 

can be documented as having been built should be recreated in a 

restoration project. 

Identify, Retain, and Preserve Materials and 

Features from the Restoration Period 

The guidance for the treatment Restoration begins with recommendations to identify the form and detailing of those architectural 

materials and features that are significant to the restoration period 

as established by historic research and documentation. Therefore, 

guidance on identifying, retaining, and preserving features from the 

restoration period is always given first. 

Protect and Maintain Materials and Features 

from the Restoration Period 

After identifying those materials and features from the restoration 

period that must be retained in the process of Restoration work, 

then protecting and maintaining them are addressed. Protection 

generally involves the least degree of intervention and is preparatory to other work. Protection includes the maintenance of materials and features from the restoration period as well as ensuring that 

the property is protected before and during restoration work. An 

overall evaluation of the physical condition of the features from 

the restoration period should always begin at this level. 

Repair (Stabilize, Consolidate, and Conserve) 

Materials and Features from the Restoration 

Period 

Next, when the physical condition of restoration-period features 

requires additional work, repairing by stabilizing, consolidating, 

and conserving is recommended. Restoration guidance focuses on 

the preservation of those materials and features that are significant to the period. In Restoration, repair may include the limited 

replacement in kind or with a compatible substitute material 

of extensively deteriorated or missing components of existing 

restoration-period features when there are surviving prototypes to 

use as a model. 

INTRODUCTION 
166

RESTORATION

Replace Extensively Deteriorated Features 

from the Restoration Period 

In Restoration, replacing an entire feature from the restoration 

period, such as a porch, that is too deteriorated to repair may be 

appropriate. Together with documentary evidence, the form and 

detailing of the historic feature should be used as a model for the 

replacement. Using the same kind of material is preferred; however, 

compatible substitute material may be considered. New work may 

be unobtrusively dated to guide future research and treatment. 

Remove Existing Features from Other Historic 

Periods 

Most buildings change over time, but in Restoration the goal is to 

depict the building as it appeared at the most significant time in its 

history. Thus, it may involve removing or altering existing historic 

features that do not represent the restoration period. Materials, features, spaces, and finishes that characterize other historical periods 

should be documented to guide future research and treatment prior 

to their alteration or removal. 

Recreate Missing Features from the 

Restoration Period 

Most Restoration projects involve recreating features that were 

significant to the building during the restoration period, such as a 

porch, but are now missing. Missing features to be replaced should 

be substantiated by documentary and physical evidence to ensure 

the restoration is accurate. Using the same materials to depict lost 

features is always the preferred approach; however, using compatible substitute material is an acceptable alternative in Restoration 

because the goal of this treatment is to replicate the appearance of 

the historic building at a particular time. 

If documentary and physical evidence are not available to provide an 

accurate recreation of missing features, the treatment Rehabilitation 

might be a better overall approach to project work. 

Code-Required Work: 

Accessibility and Life Safety 

Sensitive solutions to meeting code requirements in a Restoration 

project are an important part of protecting the historic character of 

the building. Work that must be done to meet accessibility and lifesafety requirements must also be assessed for its potential impact 

on the historic building as it is restored. 

Resilience to Natural Hazards 

Resilience to natural hazards should be addressed as part of a Restoration project. A historic building may have existing characteristics 

or features that help to address or minimize the impacts of natural hazards. These should always be used to best advantage when 

planning new adaptive treatments that have the least impact on the 

historic character of the building, its site, and setting. 

Sustainability 

Sustainability should be addressed as part of a Restoration project. 

Good preservation practice is often synonymous with sustainability. 

Existing energy-efficient features should be retained and repaired. 

New sustainability treatments should generally be limited to updating existing features and systems to have the least impact on the 

historic character of the building. 

The topic of sustainability is addressed in detail in The Secretary of 

the Interior’s Standards for Rehabilitation & Illustrated Guidelines on 

Sustainability for Rehabilitating Historic Buildings. Although specifically developed for the treatment Rehabilitation, the Sustainability 

Guidelines can be used to help guide the other treatments. 

INTRODUCTION 
167

RESTORATION

Restoration as a Treatment. When the property’s design, architectural, 

or historical significance during a particular period of time outweighs 

the potential loss of extant materials, features, spaces, and finishes that 

characterize other historical periods; when there is substantial physical 

and documentary evidence for the work; and when contemporary alterations and additions are not planned, Restoration may be considered as a 

treatment. Prior to undertaking work, a particular period of time, i.e., the 

restoration period, should be selected and justified, and a documentation 

plan for Restoration developed. 

INTRODUCTION 
RESTORATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining and preserving masonry features from the 

restoration period (such as walls, brackets, railings, cornices, 

window and door surrounds, steps, and columns) and decorative 

ornament and other details, such as tooling and bonding patterns, coatings, and color. 

Altering masonry features from the restoration period. 

Failing to document masonry features from the restoration period, 

which may result in their loss. 

Applying paint or other coatings (such as stucco) to restorationperiod masonry features, or removing them, if such treatments 

cannot be documented to the restoration period. 

Changing the type of paint or coating or the color of restorationperiod masonry features, unless the work can be substantiated by 

historical documentation. 

Protecting and maintaining masonry features from the restoration period by ensuring that historic drainage features and 

systems that divert rainwater from masonry surfaces (such as roof 

overhangs, gutters, and downspouts) are intact and functioning 

properly. 

Failing to identify and treat the causes of masonry deterioration, 

such as leaking roofs and gutters or rising damp. 

[1] (a) When it was acquired by the National Trust for Historic Preservation in 

the 1980s, Montpelier in Montpelier Station, VA, the home of James and Dolley 

Madison, had been much altered and enlarged since it was first constructed. Based 

on historical documentation and research, Montpelier was accurately restored to its 

1820s appearance when the president and his wife lived there (b). Photos: Courtesy 

of The Montpelier Foundation. 

168 MASONRY 
RESTORATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Cleaning masonry only when necessary to halt deterioration or 

remove heavy soiling. 

Cleaning masonry surfaces from the restoration period when they are 

not heavily soiled to create a “like-new” appearance, thereby needlessly introducing chemicals or moisture into historic materials. 

Carrying out masonry cleaning tests when it has been determined Cleaning masonry surfaces without testing or without sufficient time 

that cleaning is appropriate. Test areas should be examined for the testing results to be evaluated. 

to ensure that no damage has resulted and, ideally, monitored 

over a sufficient period of time to allow long-range effects to be 

predicted. 

Cleaning soiled restoration-period masonry surfaces with the Cleaning or removing paint from masonry surfaces from the restoragentlest method possible, such as using low-pressure water and tion period using most abrasive methods (including sandblasting, 

detergent and natural bristle or other soft-bristle brushes. other media blasting, or high-pressure water) which can damage the 

surface of the masonry and mortar joints. 

Using a cleaning or paint-removal method that involves water or 

liquid chemical solutions when there is any possibility of freezing 

temperatures. 

Cleaning with chemical products that will damage some types of 

masonry (such as using acid on limestone or marble), or failing to 

neutralize or rinse off chemical cleaners from masonry surfaces. 

Using biodegradable or environmentally-safe cleaning or paintremoval products. 

Using paint-removal methods that employ a poultice to which 

paint adheres, when possible, to neatly and safely remove old 

lead paint. 

Using coatings that encapsulate lead paint, when possible, 

where paint is not required to be removed to meet environmental 

regulations. 

Allowing only trained conservators to use abrasive or laser cleaning methods, when necessary, to clean hard-to-reach, highlycarved, or detailed decorative stone features. 

MASONRY 169
RESTORATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Removing damaged or deteriorated paint only to the next sound 

layer using the gentlest method possible (e.g., hand scraping) 

prior to repainting. 

Removing paint that is firmly adhered to masonry surfaces. 

Applying compatible paint coating systems to historicallypainted, restoration-period masonry following proper surface 

preparation. 

Failing to follow manufacturers’ product and application instructions when repainting masonry features. 

Repainting historically-painted masonry features with colors that 

are documented to the restoration period of the building (i.e., 

verifying through paint analysis). 

Using paint colors on historically-painted masonry features that are 

not documented to the restoration period. 

Protecting adjacent restoration-period materials when cleaning 

or removing paint from masonry features from the restoration 

period. 

Failing to protect adjacent restoration-period materials when cleaning or removing paint from masonry features from the restoration 

period. 

Evaluating the overall condition of masonry from the restoration 

period to determine whether more than protection and maintenance, such as repairs to masonry features will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

masonry features from the restoration period. 

Repairing masonry features from the restoration period by patching, splicing, consolidating, or otherwise reinforcing the masonry 

using recognized preservation methods. Repair may include 

the limited replacement in kind or with a compatible substitute 

material of those extensively deteriorated or missing components of masonry features from the restoration period when there 

are surviving prototypes (such as terra-cotta brackets or stone 

balusters) or when the replacement can be based on physical or 

historic documentation. The new work should match the old in 

material, design, scale, color, and finish. 

Removing masonry from the restoration period that could be stabilized, repaired, and conserved, or using untested consolidants and 

unskilled personnel, potentially causing further damage to materials. 

170 MASONRY 
RESTORATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Repairing masonry walls and other masonry features from the 

restoration period by repointing the mortar joints where there is 

evidence of deterioration, such as disintegrating mortar, cracks in 

mortar joints, loose bricks, or damaged plaster. 

Removing deteriorated lime mortar from the restoration period Removing restoration-period mortar that is not deteriorated from 

carefully by hand raking the joints to avoid damaging the sound joints. 

masonry. 

[2] (a) Decatur House 

in Washington, DC, was 

designed by William 

Henry Latrobe and 

constructed in 1816. (b) In 

the late-19th century, the 

façade was “modernized” 

by removing the 

limestone lintels on the 

first floor and replacing 

them with decorative 

sandstone lintels in the 

style of the period. (c) 

In the mid-20th century, 

the house was brought 

back to its original 

appearance based on 

historic documentation. 

Photos: The White House 

Historical Association 

and Decatur House, a 

National Trust Site. 

MASONRY 171
RESTORATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Using power tools only on horizontal joints on restoration-period 

brick masonry in conjunction with hand chiseling to remove hard 

mortar that is deteriorated or that is a non-historic material which 

is causing damage to the masonry units. Mechanical tools should 

be used only by skilled masons in limited circumstances and 

generally not on short, vertical joints in brick masonry. 

Allowing unskilled workers to use masonry saws or mechanical tools 

to remove deteriorated mortar from joints prior to repointing. 

Duplicating historic mortar joints in strength, composition, color, Repointing masonry units with mortar of high Portland cement 

and texture when repointing is necessary. In some cases, a lime- content (unless it is the content of the mortar from the restoration 

based mortar may also be considered when repointing Portland period). 

cement mortar joints because it is more flexible. 

Duplicating restoration-period mortar joints in width and joint 

profile when repointing is necessary. 

Using “surface grouting” or a “scrub” coating technique, such as 

a “sack rub” or “mortar washing,” to repoint exterior masonry units 

from the restoration period instead of traditional repointing methods. 

Changing the width or joint profile when repointing masonry from 

the restoration period. 

[3] Not Recommended: 

Although the Dutchman 

stone repair has been 

well executed, the 

replacement stone is not 

a good color match. 

172 MASONRY 
RESTORATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Repairing stucco from the restoration period by removing the Removing sound stucco from the restoration period or repairing with 

damaged material and patching with new material that duplicates new stucco that is different in composition from the historic stucco. 

the historic stucco in strength, composition, color, and texture. 

Patching stucco or concrete from the restoration period without 

removing the source of deterioration. 

Replacing deteriorated stucco from the restoration period with 

synthetic stucco, an exterior finish and insulation system (EFIS), or 

other non-traditional materials. 

Using mud plaster or a compatible lime-plaster adobe render, 

when appropriate, to repair adobe from the restoration period. 

Applying cement stucco, unless it already exists, to adobe from the 

restoration period. 

Sealing joints in concrete from the restoration period with appropriate flexible sealants and backer rods, when necessary. Repointing masonry units from the restoration period (other than 

concrete) with a synthetic caulking compound instead of mortar. 

Cutting damaged concrete from the restoration period back to Patching concrete from the restoration period without removing the 

remove the source of deterioration, such as corrosion on metal source of deterioration. 

reinforcement bars. The new patch must be applied carefully 

so that it will bond satisfactorily with and match the historic 

concrete. 

Using a non-corrosive, stainless-steel anchoring system when 

replacing damaged stone, concrete, or terra-cotta units from the 

restoration period that have failed. 

Repairing masonry features from the restoration period by patch- Removing masonry from the restoration period that could be staing, splicing, consolidating, or otherwise reinforcing the masonry bilized, repaired, and conserved, or using untested consolidants, 

using recognized preservation methods. Repair may include improper repair techniques, or unskilled personnel, potentially 

the limited replacement in kind or with a compatible substitute causing further damage to materials. 

material of those extensively deteriorated or missing components of masonry features from the restoration period when there Replacing an entire masonry feature from the restoration period, 

are surviving prototypes (such as terra-cotta brackets or stone such as a cornice or balustrade, when repair of the masonry and 

balusters) or when the replacement can be based on physical or limited replacement of deteriorated or missing components are 

historic documentation. The new work should match the old in appropriate. 

material, design, scale, color, and finish. 

MASONRY 173
174

RESTORATION

[4] (a) Over the years 

terra-cotta cladding 

had been replaced on 

the lower floors of this 

early-20th century bank 

building with a storefront 

and incompatible 

windows. (b) A 1936 

photograph of the 

building provided the 

documentation to restore 

its historic appearance. 

(c) Glass fiber reinforced 

plastic (GRFP) was 

chosen as a substitute 

material, and samples 

were made in a variety 

of colors and textures to 

obtain the best match 

for the missing and 

damaged terra cotta. (d) 

This photo taken after 

restoration shows that 

the GFRP replacements 

successfully blend in with 

the original terra cotta. 

Photo (d): Blamonet at 

English Wikipedia. 

(a) 

(c) 

(d) (b) 

MASONRY 
RESTORATION

MASONRY: STONE, BRICK, TERRA COTTA, CONCRETE, ADOBE, STUCCO, AND MORTAR 

RECOMMENDED NOT RECOMMENDED 

Applying non-historic surface treatments, such as water-repellent Applying waterproof, water-repellent, or other coatings that are not 

coatings, to masonry from the restoration period only after from the restoration period (such as stucco) to masonry as a substirepointing and only if masonry repairs have failed to arrest water tute for repointing and masonry repairs. 

penetration problems. 

Applying permeable, anti-graffiti coatings to masonry from the 

restoration period when appropriate. 

Applying water-repellent or anti-graffiti coatings that change the 

historic appearance of the masonry from the restoration period or 

that may trap moisture if the coating is not sufficiently permeable. 

Replacing in kind an entire masonry feature from the restoration Removing a masonry feature from the restoration period that is 

period that is too deteriorated to repair (if the overall form and unrepairable and not replacing it, or replacing it with a new feature 

detailing are still evident) using the physical evidence as a model that does not match. 

to reproduce the feature. Examples can include a large section of 

a wall, a cornice, balustrade, pier, or parapet. If using the same Using a substitute material for the replacement that does not 

kind of material is not feasible, then a compatible substitute convey the same appearance of the surviving components of the 

material may be considered. The new work may be unobtrusively masonry. 

dated to guide future research and treatment. 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic masonry features that would 

be retained in Preservation and Rehabilitation treatments; and the replacement of missing masonry features from the restoration period using all new 

materials. 

Removing Existing Features from Other Historic Periods 

Removing masonry features from other historic periods, such as a 

door surround, porch, or steps. 

Failing to remove a masonry feature from another period, thereby 

confusing the depiction of the building’s appearance from the 

restoration period. 

Documenting masonry features dating from other periods prior to 

their alteration or removal. If possible, selected examples of these 

features or materials should be stored for future research. 

Failing to document masonry features from other historic periods 

that are removed from the building so that a valuable portion of the 

historic record is lost. 

Recreating Missing Features from the Restoration Period 

Recreating a missing masonry feature that existed during the Constructing a masonry feature that was part of the original design 

restoration period based on documentary and physical evidence; for the building but was never actually built, or a feature which 

for example, duplicating a terra-cotta bracket or stone balus­ was thought to have existed during the restoration period but which 

trade. The new work may be unobtrusively dated to guide future cannot be documented. 

research and treatment. 

MASONRY 175
RESTORATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND 

OTHER FUNCTIONAL AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving wood features from the res- Altering wood features from the restoration period. 

toration period (such as siding, cornices, brackets, window and 

door surrounds, and steps) and their paints, finishes, and colors. Failing to document wood features from the restoration period, 

which may result in their loss. 

Applying paint or other coatings to restoration-period wood features, 

or removing them, if such treatments cannot be documented to the 

restoration period. 

Changing the type of paint or coating or the color of restorationperiod wood features, unless the work can be substantiated by 

historical documentation. 

Protecting and maintaining wood features from the restoration 

period by ensuring that historic drainage features that divert rainwater from wood surfaces (such as roof overhangs, gutters, and 

downspouts) are intact and functioning properly. 

Failing to identify and treat the causes of wood deterioration, such 

as faulty flashing, leaking gutters, cracks and holes in siding, deteriorated caulking in joints and seams, plant material growing too 

close to wood surfaces, or insect or fungal infestation. 

Applying chemical preservatives or paint to wood features from 

the restoration period that are subject to weathering, such as 

exposed beam ends, outriggers, or rafter tails. 

Using chemical preservatives that can change the appearance of 

wood features from the restoration period. 

Implementing an integrated pest management plan to identify 

appropriate preventive measures to guard against insect damage, 

such as installing termite guards, fumigating, and treating with 

chemicals. 

Retaining coatings from the restoration period (such as paint) 

that protect the wood from moisture and ultraviolet light. Paint 

removal should be considered only when there is paint surface 

deterioration and as part of an overall maintenance program 

which involves repainting or applying other appropriate coatings. 

Stripping restoration-period paint or other coatings from wood features without recoating them. 

Using biodegradable or environmentally-safe cleaning or paintremoval products. 

176 WOOD 
RESTORATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND 

OTHER FUNCTIONAL AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Using thermal devices (such as infrared heaters) carefully to Using a thermal device to remove paint from wood features without 

remove paint, when it is so deteriorated that total removal is first checking for and removing any flammable debris behind them. 

necessary prior to repainting. 

Using thermal devices without limiting the amount of time the wood 

is exposed to heat. 

Using paint-removal methods that employ a poultice to which 

paint adheres, when possible, to neatly and safely remove old 

lead paint. 

Using coatings that encapsulate lead paint, when possible, where 

the paint is not required to be removed to meet environmental 

regulations. 

Using chemical strippers primarily to supplement other methods Failing to neutralize the wood thoroughly after using chemical paint 

such as hand scraping, hand sanding, and thermal devices. removers so that new paint may not adhere. 

Removing paint from detachable, restoration-period wood features 

by soaking them in a caustic solution which can roughen the surface, split the wood, or result in staining from residual acid leaching out through the wood. 

Removing damaged or deteriorated paint to the next sound layer Using potentially-damaging paint-removal methods on restorationusing the gentlest method possible (e.g., hand scraping and hand period wood surfaces, such as open-flame torches, orbital sanders, 

sanding) prior to repainting. abrasive methods (including sandblasting, other media blasting, or 

high-pressure water), or caustic paint-removers. 

Removing paint that is firmly adhered to wood surfaces. 

Applying compatible paint coating systems to historically-painted 

wood following proper surface preparation. 

Failing to follow manufacturers’ product and application instructions when repainting wood features from the restoration period. 

Repainting historically-painted wood features with colors that are 

documented to the restoration period of the building (i.e., verifying through paint analysis). 

Using paint colors on historically-painted wood features that are not 

documented to the restoration period. 

WOOD 177
RESTORATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND 

OTHER FUNCTIONAL AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

Protecting adjacent restoration-period materials when cleaning or 

removing paint from wood features from the restoration period. 

Failing to protect adjacent restoration-period materials when 

cleaning or removing paint from wood features from the restoration 

period. 

Evaluating the overall condition of wood features from the restoration period to determine whether more than protection and 

maintenance, such as repairs to wood features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

wood features from the restoration period. 

Repairing wood features from the restoration period by patching, Removing wood features from the restoration period that could be 

splicing, consolidating, or otherwise reinforcing the wood using stabilized, repaired, and conserved, or using untested consolidants 

recognized preservation methods. Repair may include the limited or unskilled personnel, potentially causing further damage to hisreplacement in kind or with a compatible substitute material of toric materials. 

those extensively deteriorated or missing components of features 

from the restoration period when there are surviving prototypes Replacing an entire wood feature from the restoration period, such 

(such as brackets, molding, or sections of siding) or when the as a cornice or porch railing, when repair of the wood and limited 

replacement can be based on physical or historic documentation. replacement of deteriorated or missing components are appropriate. 

The new work should match the old in material, design, scale, 

color, and finish. 

Replacing in kind an entire wood feature from the restoration Removing a wood feature from the restoration period that is unreperiod that is too deteriorated to repair (if the overall form and pairable and not replacing it, or replacing it with a new feature that 

detailing are still evident) using the physical evidence as a model does not match. 

to reproduce the feature or when the replacement can be based 

on historic documentation. Examples can include a cornice, Using substitute material for the replacement that does not convey 

entablature, or a balustrade. If using the same kind of material the same appearance of the surviving components of the wood feais not feasible, then a compatible substitute material may be ture from the restoration period or that is physically incompatible. 

considered. The new work may be unobtrusively dated to guide 

future research and treatment. 

178 WOOD 
RESTORATION

WOOD: CLAPBOARD, WEATHERBOARD, SHINGLES, AND 

OTHER FUNCTIONAL AND DECORATIVE ELEMENTS 

RECOMMENDED NOT RECOMMENDED 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic masonry features that would be 

retained in Preservation and Rehabilitation treatments; and the replacement of missing wood features from the restoration period using all new materials. 

Removing Existing Features from Other Historic Periods 

Removing wood features from other historic periods, such as a 

door surround, porch, or steps. 

Failing to remove a wood feature from another period, thereby confusing the depiction of the building’s appearance from the restoration period. 

Documenting wood features dating from other periods prior to 

their alteration or removal. If possible, selected examples of these 

features or materials should be stored for future research. 

Recreating Missing Features from the Restoration Period 

Recreating a missing wood feature that existed during the restoration period based on documentary and physical evidence; for 

example, duplicating a wood dormer or porch 

Failing to document wood features from other historic periods that 

are removed from the building so that a valuable portion of the 

historic record is lost. 

Constructing a wood feature that was part of the original design for 

the building but was never actually built, or a feature which was 

thought to have existed during the restoration period but cannot be 

documented. 

[5] New wood trim pieces 

were milled to match the 

few remaining historic 

features to replace those 

that were missing. 

WOOD 179
RESTORATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving metal features from the 

restoration period (such as columns, capitals, pilasters, spandrel 

panels, or stairways) and their finishes and colors. The type of 

metal should be identified prior to work because each metal has 

its own properties and may require a different treatment. 

Altering metal features from the restoration period. 

Failing to document metal features from the restoration period, 

which may result in their loss. 

Applying paint or other coatings to restoration-period metal features, or removing them, if such treatments cannot be documented 

to the restoration period. 

Changing the type of paint or coating or the color of restorationperiod metal features, unless the work can be substantiated by 

historical documentation. 

Protecting and maintaining metals from the restoration period Failing to identify and treat the causes of corrosion of restorationfrom corrosion by providing proper drainage so that water does period metal features such as moisture from leaking roofs or gutnot stand on flat, horizontal surfaces or accumulate in curved ters. 

decorative features. 

Cleaning metals from the restoration period, when necessary, to 

remove corrosion prior to repainting or applying other appropriate 

protective coatings. 

Failing to reapply coating systems after cleaning metals from the 

restoration period that require protection from corrosion. 

Removing the patina from restoration-period metal features. The 

patina may be a protective layer on some metals (such as bronze or 

copper) as well as a distinctive finish. 

Identifying the particular type of metal from the restoration Using cleaning methods which alter or damage the restorationperiod prior to any cleaning procedure and then testing to ensure period color, texture, and finish of the metal, or cleaning when it is 

that the gentlest cleaning method possible is selected; or alterna­ inappropriate for the metal. 

tively, determining that cleaning is inappropriate for the particular metal. 

Using non-corrosive chemical methods to clean soft metals from Cleaning soft metals from the restoration period (such as lead, tinthe restoration period (such as lead, tinplate, terneplate, copper, plate, terneplate, copper, and zinc) with abrasive methods (includand zinc) whose finishes can be easily damaged by abrasive ing sandblasting, other media blasting, or high-pressure water) 

methods. which will damage the surface of the metal. 

180 METALS 
RESTORATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Using the least abrasive cleaning method on hard metals from 

the restoration period (such as cast iron, wrought iron, and steel) 

to remove paint buildup and corrosion. If hand scraping and wire 

brushing have Using the least abrasive cleaning method on hard 

metals from the restoration period (such as cast iron, wrought iron, 

and steel) to remove paint buildup and corrosion. If hand scraping 

and wire brushing have proven ineffective, low-pressure abrasive 

methods may be used as long as they do not damage the surface. 

Using high-pressure abrasive techniques without first trying gentler 

cleaning methods prior to cleaning cast iron, wrought iron, or steel. 

Applying appropriate paint or other coating systems to historically-painted, restoration-period metal features after cleaning to 

protect them from corrosion. 

Applying paint or other coatings to metals (such as copper, bronze, 

or stainless steel) if they were not coated during the restoration 

period. 

Repainting historically-painted metal features with colors that are 

documented to the restoration period of the building (i.e., verifying through paint analysis). 

Using paint colors on historically-painted metal features that are 

not documented to the restoration period of the building. 

Applying an appropriate protective coating (such as lacquer 

or wax) to an architectural metal feature that was historically 

unpainted, such as a bronze door, that is subject to heavy use. 

Protecting adjacent restoration-period materials when working on 

metal features from the restoration period. 

Failing to protect adjacent restoration-period materials when working on metal features from the restoration period. 

Evaluating the overall condition of metals from the restoration 

period to determine whether more than protection and maintenance, such as repairs to metal features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

metal features from the restoration period. 

Repairing metal features from the restoration period by reinforc- Removing metal features from the restoration period that could be 

ing the metal by using recognized preservation methods. Repair stabilized, repaired, and conserved, or using improper repair techmay include the limited replacement in kind or with a compatible niques, or untrained personnel, potentially causing further damage 

substitute material of those extensively deteriorated or missing to historic materials. 

parts of features when there are surviving prototypes (such as 

porch balusters, column capitals or bases, storefronts, railings, or Replacing an entire metal feature from the restoration period, such 

porch cresting) or when the replacement can be based on physi­ as a column or balustrade, when repair of the metal and limited 

cal or historic documentation. The new work should match the replacement of deteriorated or missing components are appropriate. 

old in material, design, scale, color, and finish. 

METALS 181
182

RESTORATION

[6] Preliminary 

work before starting 

restoration revealed 

that the columns and 

the decorative shingles 

ornamenting the top 

floor of this historic 

building were fabricated 

of metal to imitate 

the red sandstone 

used elsewhere on the 

building. 

METALS 
RESTORATION

METALS: WROUGHT AND CAST IRON, STEEL, PRESSED METAL, TERNEPLATE, 

COPPER, ALUMINUM, AND ZINC 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire metal feature from the restoration Removing a metal feature from the restoration period that is unreperiod that is too deteriorated to repair (if the overall form and pairable and not replacing it, or replacing it with a new feature that 

detailing are still evident) using the physical evidence as a model does not match. 

to reproduce the feature or when the replacement can be based 

on historic documentation. Examples of such a feature could Using a substitute material for the replacement that does not 

include cast-iron porch steps or steel-sash windows. If using the convey the same appearance of the surviving components of the 

same kind of material is not feasible, then a compatible sub- metal feature from the restoration period or that is physically or 

stitute material may be considered as long as it has the same chemically incompatible. 

appearance as the original. The new work may be unobtrusively 

dated to guide future research and treatment. 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic masonry features that would be 

retained in Preservation and Rehabilitation treatments; and the replacement of missing metal features from the restoration period using all new materials. 

Removing Existing Features from Other Historic Periods 

Removing metal features from other historic periods, such as a 

cast-iron porch railing or aluminum windows. 

Failing to remove a metal feature from another period, thereby confusing the depiction of the building’s appearance from the restoration period. 

Documenting metal features dating from other periods prior to 

their alteration or removal. If possible, selected examples of these 

features or materials should be stored for future research. 

Failing to document metal features from other historic periods that 

are removed from the building so that a valuable portion of the 

historic record is lost. 

Recreating Missing Features from the Restoration Period 

Recreating a missing metal feature that existed during the resto- Constructing a metal feature that was part of the original design for 

ration period based on documentary and physical evidence; for the building but was never actually built, or a feature which was 

example, duplicating a cast-iron storefront or porch. thought to have existed during the restoration period but cannot be 

documented. 

METALS 183
RESTORATION

ROOFS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving roofs from the restoration Altering roof and roofing materials from the restoration period. 

period and their functional and decorative features. The form of 

the roof (gable, hipped, gambrel, flat, or mansard) is significant, Failing to document roof features from the restoration period, which 

as are its decorative and functional features (such as cupolas, may result in their loss. 

cresting, parapets, monitors, chimneys, weather vanes, dormers, 

ridge tiles, and snow guards), roofing materials (such as slate, Changing the type of paint or coating or the color of restorationwood, clay tile, metal, roll roofing, or asphalt shingles) and size, period roof features, unless the work can be substantiated by 

color, and patterning. historical documentation. 

Stripping the roof of sound historic roofing material (such as slate, 

clay tile, wood, or metal) from the restoration period. 

Protecting and maintaining a roof from the restoration period Failing to clean and maintain gutters and downspouts so that water 

by cleaning gutters and downspouts and replacing deteriorated and debris collect and cause damage to roof fasteners, sheathing, 

flashing. Roof sheathing should also be checked for indications and the underlying structure. 

of moisture due to leaks or condensation. 

Providing adequate anchorage for roofing material from the 

restoration period to guard against wind damage and moisture 

penetration. 

Allowing flashing, caps, and exposed roof fasteners to corrode, 

which accelerates deterioration. 

Protecting a leaking roof with a temporary waterproof membrane 

with a synthetic underlayment, roll roofing, plywood, or a tarpaulin until it can be repaired. 

Leaving a leaking roof unprotected so that accelerated deterioration 

of historic building materials from the restoration period (such as 

masonry, wood, plaster, paint, and structural members) results. 

Repainting a roofing material from the restoration period that Failing to repaint a roofing material from the restoration period that 

requires a protective coating and was painted historically (such requires a protective coating and was painted historically as part of 

as a terneplate metal roof or gutters) as part of regularly-sched­ regularly-scheduled maintenance. 

uled maintenance. 

Protecting a restoration-period roof covering when working on 

other roof features from the restoration period. 

Failing to protect restoration-period roof coverings when working on 

other roof features from the restoration period. 

Evaluating the overall condition of the roofing materials from the 

restoration period to determine whether more than protection and 

maintenance, such as repairs to roof features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

roof features from the restoration period. 

184 ROOFS 
185

RESTORATION

[7 a-b] This crumbling chimney was restored to 

its historic appearance using matching bricks. 

[8] The missing steeple of this historic 

church was replaced with a new steeple 

made of a substitute material that, from the 

street below, closely resembles the original 

steeple. Photo: en.Wikipedia. 

ROOFS 
RESTORATION

ROOFS 

RECOMMENDED NOT RECOMMENDED 

Repairing a roof from the restoration period by reinforcing the 

materials that comprise the roof using recognized preservation 

methods. Repair may include the limited replacement in kind or 

with a compatible substitute material of those extensively deteriorated or missing components of features when there are surviving 

prototypes (such as cupola louvers, cresting, dormer roofing, roof 

monitors, or slate or tile on a main roof) or when replacement can 

be based on physical or historic documentation. The new work 

should match the old in materials, design, scale, color, and finish. 

Replacing an entire roof feature from the restoration period, such as 

a dormer, when repair of the roofing materials and limited replacement of deteriorated or missing components are feasible. 

Failing to reuse intact slate or tile from the restoration period when 

only the roofing substrate or fasteners need replacement. 

Replacing in kind an entire roof covering or feature from the Removing a roof feature from the restoration period that is unrepairrestoration period that is too deteriorated to repair (if the overall able, such as a chimney or dormer, and not replacing it, or replacform and detailing are still evident) using the physical evidence ing it with a feature that does not match. 

as a model to reproduce the feature or when the replacement can 

be based on historic documentation. Examples of such a feature Using a substitute material for the replacement of a single elecould include a large section of roofing, a dormer, or a chimney. ment of a roof (such as a tile or slate) or an entire feature that does 

If using the same kind of material is not feasible, then a compat­ not convey the same appearance of the surviving components of 

ible substitute material may be appropriate. the roof feature from the restoration period or that is physically or 

chemically incompatible. 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic masonry features that would be 

retained in Preservation and Rehabilitation treatments; and the replacement of missing roof features from the restoration period using all new materials. 

Removing Existing Features from Other Historic Periods 

Removing roofs or roof features from other historic periods, such 

as a dormer or asphalt roofing. 

Failing to remove a roof feature from another period, thereby confusing the depiction of the building’s appearance from the restoration period. 

Documenting roof features dating from other periods prior to their Failing to document roofing materials and roof features from other 

alteration or removal. If possible, selected examples of these historic periods that are removed from the building so that a valufeatures or materials should be stored for future research. able portion of the historic record is lost. 

Recreating Missing Features from the Restoration Period 

Recreating a missing roofing material or roof feature that existed Constructing a roof feature that was part of the original design for 

during the restoration period based on documentary and physical the building but was never actually built, or a feature which was 

evidence; for example, duplicating a former dormer or cupola. thought to have existed during the restoration period but cannot be 

documented. 

186 ROOFS 
RESTORATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving windows from the restoration period and their functional and decorative features. The 

window material and how the window operates (e.g., double 

hung, casement, awning, or hopper) are significant, as are its 

components (including sash, muntins, ogee lugs, glazing, pane 

configuration, sills, mullions, hardware, casings or brick molds) 

and related features, such as shutters. 

Altering windows or window features from the restoration period. 

Failing to document window features from the restoration period, 

which may result in their loss. 

Applying paint or other coatings to restoration-period window features, or removing them, if such treatments cannot be documented 

to the restoration period. 

Changing the type of paint or coating or the color of restorationperiod windows, unless the work can be substantiated by historical 

documentation. 

Stripping windows of sound historic material (such as wood or 

metal) from the restoration period. 

Conducting an in-depth survey of the condition of existing win- Replacing windows from the restoration period solely because of 

dows from the restoration period early in the planning process so peeling paint, broken glass, stuck sash, or high air infiltration. 

that repair, upgrading, and, if necessary, possible replacement These conditions, in themselves, do not indicate that windows are 

options can be fully explored. beyond repair. 

Protecting and maintaining the restoration-period wood or metal Failing to protect and maintain window materials from the restorawhich comprises the window jamb, sash, and trim through appro­ tion period on a cyclical basis so that deterioration of the window 

priate surface treatments such as cleaning, paint removal, and results. 

reapplication of the same protective coatings. 

Protecting windows from the restoration period against vandalism before work begins by covering them and by installing alarm 

systems that are keyed into local protection agencies. 

Leaving windows unprotected before work begins, thereby also 

allowing the interior to be damaged if it can be accessed through 

unprotected windows. 

Installing impact-resistant glazing, when necessary for security, 

so that it is compatible with the historic windows from the restoration period and does not damage them or negatively impact 

their character. 

Installing impact-resistant glazing, when necessary, for security that 

is not compatible with the historic windows from the restoration 

period and damages them or negatively impacts their character. 

WINDOWS 187
RESTORATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

[9] Historic window and shutter 

hardware such as that shown here 

should be retained and repaired in a 

restoration project. 

Protecting restoration-period windows when working on other 

features of the building. 

Failing to protect restoration-period windows when working on other 

features of the building. 

Protecting and retaining historic glass from the restoration 

period when replacing putty or repairing other components of the 

window. 

Failing to protect historic glass from the restoration period when 

making repairs. 

Sustaining the historic operability of windows from the restoration Failing to maintain windows and window components from the resperiod by lubricating friction points and replacing broken com­ toration period so that windows are inoperable, or sealing operable 

ponents of the operating system (such as hinges, latches, sash sash permanently. 

chains or cords) and replacing deteriorated gaskets or insulating 

units. Failing to repair and reuse window hardware from the restoration 

period, such as sash lifts, latches, and locks. 

Evaluating the overall condition of windows from the restoration Failing to undertake adequate measures to ensure the protection of 

period to determine whether more than protection and mainte­ window features from the restoration period. 

nance, such as repairs to windows and window features, will be 

necessary. 

Repairing window frames and sash from the restoration period Replacing an entire window from the restoration period when repair 

by patching, splicing, consolidating, or otherwise reinforcing of materials and limited replacement in kind are appropriate. 

them using recognized preservation methods. Repair may include 

the limited replacement in kind or with a compatible substitute Removing a window from the restoration period that is unrepairable 

material of those extensively deteriorated, broken, or missing and not replacing it, or replacing it with a new window that does not 

components of windows when there are surviving prototypes match. 

(such as sash, sills, hardware, or shutters) or when the replacement can be based on physical or historic documentation. The 

new work should match the old in material, design, scale, color, 

and finish. 

188 WINDOWS 
RESTORATION

WINDOWS 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire window from the restoration period Removing a window from the restoration period that is unrepairable 

that is too deteriorated to repair (if the overall form and detail- and not replacing it, or replacing it with a new window that does not 

ing are still evident) using the physical evidence as a model to match. 

reproduce the feature or when the replacement can be based on 

historic documentation. If using the same kind of material is not Using substitute material for the replacement that does not convey 

feasible, then a compatible substitute material may be consid­ the same appearance of the surviving components of the window 

ered. The new work may be unobtrusively dated to guide future from the restoration period or that is physically incompatible. 

research and treatment. 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic masonry features that would be 

retained in Preservation and Rehabilitation treatments; and the replacement of missing window features from the restoration period using all new materials.

 Removing Existing Features from Other Historic Periods 

Removing windows or window features from other historic period, 

such as the glazing pattern or inappropriate shutters. 

Failing to remove a window or window feature from another period, 

thereby confusing the depiction of the building’s appearance from 

the restoration period. 

Documenting window features dating from other periods prior to Failing to document window features from other historic periods 

their alteration or removal. If possible, selected examples of these that are removed from the building so that a valuable portion of the 

features or materials should be stored for future research. historic record is lost. 

Recreating Missing Features from the Restoration Period 

Recreating a missing window or window feature that existed Constructing a window feature that was part of the original design 

during the restoration period based on documentary and physical for the building but was never actually built, or constructing a feaevidence; for example, duplicating a hoodmold or shutter. ture which was thought to have existed during the restoration period 

but cannot be documented. 

WINDOWS 189
RESTORATION

ENTRANCES AND PORCHES 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving entrances and porches 

from the restoration period and their functional and decorative 

features. The materials themselves (including wood, masonry, 

and metal) are important, as are their features, such as doors, 

transoms, pilasters, columns, balustrades, stairs, roofs, and 

projecting canopies. 

Altering entrances and porch features from the restoration period. 

Failing to document entrance and porch features from the restoration period, which may result in their loss. 

Applying paint or other coatings to restoration-period entrance and 

porch features, or removing them, if such treatments cannot be 

documented to the restoration period. 

Changing the type of paint or coating or the color of restorationperiod entrance and porch features, unless the work can be substantiated by historical documentation. 

Stripping entrances and porches of sound material from the restoration period, such as wood, cast iron, tile, or brick. 

Protecting and maintaining the masonry, wood, and metals which Failing to protect and maintain materials from the restoration period 

comprise entrances and porches from the restoration period on a cyclical basis so that deterioration of the entrance or porch 

through appropriate surface treatments, such as cleaning, rust results. 

removal, paint removal, and reapplication of protective coatings. 

Protecting entrances and porches against arson and vandalism 

before work begins by covering them and by installing alarm 

systems keyed into local protection agencies. 

Leaving entrances and porches unprotected and subject to vandalism before work begins, thereby also allowing the interior to be 

damaged if it can be accessed through unprotected entrances. 

Protecting entrance and porch features from the restoration 

period when working on other features of the building. 

Failing to protect entrances and porches from the restoration period 

when working on other features of the building. 

Evaluating the overall condition of entrances and porches from 

the restoration period to determine whether more than protection 

and maintenance, such as repairs to entrance and porch features, 

will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

entrance and porch features from the restoration period. 

190 ENTRANCES AND PORCHES 
RESTORATION

ENTRANCES AND PORCHES 

RECOMMENDED 

Repairing entrances and porches from the restoration period 

by reinforcing them or replacing deteriorated materials using 

recognized preservation methods. Repair may include the limited 

replacement in kind or with a compatible substitute material of 

those extensively deteriorated or missing components of features when there are surviving prototypes (such as balustrades, 

columns, and stairs) or when the replacement can be based on 

physical or historic documentation. The new work should match 

the old in material, design, scale, color, and finish. 

NOT RECOMMENDED 

Replacing an entire entrance or porch feature from the restoration 

period when the repair of materials and limited replacement of 

deteriorated or missing components are feasible. 

[10] (a) The entrance 

of this house had been 

altered over the years, 

including removal of the 

porch floor and steps. 

(b) This photograph 

shows the house after 

the porch and steps 

were restored to their 

historic appearance. 

ENTRANCES AND PORCHES 191
RESTORATION

ENTRANCES AND PORCHES 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire entrance or porch from the restora- Removing an entrance or porch feature from the restoration period 

tion period that is too deteriorated to repair (if the overall form that is unrepairable and not replacing it, or replacing with a new 

and detailing are still evident) using the physical evidence as a entrance or porch that does not match. 

model to reproduce the feature or when the replacement can be 

based on historic documentation. If using the same kind of mate- Using a substitute material for the replacement that does not 

rial is not feasible, then a compatible substitute material may be convey the same appearance of the surviving components of 

considered. The new work may be unobtrusively dated to guide restoration-period entrance or porch features or that is otherwise 

future research and treatment. incompatible. 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic entrances and porches or their features that would be retained in Preservation and Rehabilitation treatments; and the replacement of missing entrances and porches or their features from the 

restoration period using all new materials. 

Removing Existing Features from Other Historic Periods 

Removing entrances and porches and their features from other 

historic periods, such as a porch railing. 

Failing to remove an entrance or porch feature from another period, 

thereby confusing the depiction of the building’s appearance from 

the restoration period. 

Documenting entrance and porch features dating from other Failing to document entrance and porch features from other historic 

periods prior to their alteration or removal. If possible, selected periods that are removed from the building so that a valuable porexamples of these features or materials should be stored for tion of the historic record is lost. 

future research. 

Recreating Missing Features from the Restoration Period 

Recreating a missing entrance or porch or its features that Constructing an entrance or porch feature that was part of the 

existed during the restoration period based on documentary and original design for the building but was never actually built, or 

physical evidence; for example, duplicating a transom or porch constructing a feature which was thought to have existed during the 

column. restoration period but cannot be documented. 

192 ENTRANCES AND PORCHES 
RESTORATION

STOREFRONTS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving storefronts from the restoration period and their functional and decorative features. The 

storefront materials (including wood, masonry, metals, ceramic 

tile, clear glass, and pigmented structural glass) and the configuration of the storefront are significant, as are its features, such as 

display windows, base panels, bulkheads, signs, doors, transoms, 

kick plates, corner posts, piers, and entablatures. 

Altering storefronts and their features from the restoration period. 

Failing to document storefront features from the restoration period, 

which may result in their loss. 

Applying paint or other coatings to restoration-period storefront features, or removing them, if such treatments cannot be documented 

to the restoration period. 

Changing the type of paint or coating or the color of restorationperiod storefront features, unless the work can be substantiated by 

historical documentation. 

Stripping storefronts of material from the restoration period, such 

as wood, cast iron, ceramic tile, pigmented structural glass, or 

masonry. 

Protecting and maintaining masonry, wood, glass, ceramic tile, Failing to protect and maintain storefront materials from the restoand metals which comprise storefronts from the restoration ration period on a cyclical basis so that deterioration of storefront 

period through appropriate surface treatments, such as cleaning, features results. 

paint removal, and reapplication of protective coatings. 

Replacing storefront windows from the restoration period rather 

than maintaining all the components of the window system. 

Protecting storefronts against arson and vandalism before work 

begins by covering windows and doors and by installing alarm 

systems keyed into local protection agencies. 

Leaving the storefront unprotected and subject to vandalism before 

work begins, thereby also allowing the interior to be damaged if it 

can be accessed through unprotected entrances. 

Protecting restoration-period storefront features when working on 

other features of the building. 

Failing to protect the restoration-period storefront when working on 

other features of the building. 

Evaluating the overall condition of the storefront from the restoration period to determine whether more than protection and maintenance, such as repairs to storefront features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

storefront features from the restoration period. 

STOREFRONTS 193
194

RESTORATION

[11] (a) Some of the materials on the front of this historic 

building had been previously replaced, but the façade 

retained its essential distinctive features and design. 

(b) A vintage postcard of the building (far left) provided 

sufficient documentation to restore the façade to its 

historic 1945 appearance, using spandrel glass as a 

replacement for the original Carrara glass (c). Photo (b): 

Courtesy Kelsey & Associates. 

STOREFRONTS 
RESTORATION

STOREFRONTS 

RECOMMENDED NOT RECOMMENDED 

Repairing storefronts from the restoration period by reinforcing Replacing an entire storefront from the restoration period when 

them or replacing deteriorated materials using recognized pres- repair of materials and limited replacement of deteriorated or misservation methods. Repair may include the limited replacement ing components are feasible. 

in kind or with compatible substitute materials of those extensively deteriorated or missing components of features when there 

are surviving prototypes (such as transoms, pilasters, or signs) 

or when the replacement can be based on physical or historic 

documentation. The new work should match the old in material, 

design, scale, color, and finish. 

Replacing in kind an entire storefront from the restoration period Removing a storefront from the restoration period that is unrepairthat is too deteriorated to repair (if the overall form and detail- able and not replacing it, or replacing it with a new storefront that 

ing are still evident) using the physical evidence as a model to does not match. 

reproduce the feature or when the replacement can be based on 

historic documentation. If using the same kind of material is not Using a substitute material for the replacement that does not 

feasible, then a compatible substitute material may be consid­ convey the same appearance of the surviving components of the 

ered. The new work may be unobtrusively dated to guide future restoration-period storefront or that is physically incompatible. 

research and treatment. 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic entrances and porches or their features that would be retained in Preservation and Rehabilitation treatments; and the replacement of missing storefronts or their features from the restoration 

period using all new materials. 

Removing Existing Features from Other Historic Periods 

Removing storefronts and their features from other historic periods, such as later cladding or signage. 

Failing to remove a storefront feature from another period, thereby 

confusing the depiction of the building’s appearance from the 

restoration period. 

Documenting storefront features dating from other periods prior Failing to document storefront features from other historic periods 

to their alteration or removal. If possible, selected examples of that are removed from the building so that a valuable portion of the 

these features or materials should be stored for future research. historic record is lost. 

Recreating Missing Features from the Restoration Period 

Recreating a missing storefront or storefront feature that existed Constructing a storefront feature that was part of the original design 

during the restoration period based on documentary and physical for the building but was never actually built, or constructing a feaevidence; for example, duplicating a display window or transom. ture which was thought to have existed during the restoration period 

but which cannot be documented. 

STOREFRONTS 195
RESTORATION

CURTAIN WALLS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving curtain wall systems from Altering curtain wall components from the restoration period. 

the restoration period and their components. The design of the 

curtain wall is significant, as are its component materials (metal Failing to document curtain wall systems from the restoration 

stick framing and panel materials, such as clear or spandrel period, which may result in their loss. 

glass, stone, terra cotta, metal, and fiber-reinforced plastic), 

appearance (e.g., glazing color or tint, transparency, and reflectiv- Replacing curtain wall features from the restoration period instead 

ity), and whether the glazing is fixed, operable, or louvered glass of repairing or replacing only the deteriorated components. 

panels. How a curtain wall is engineered and fabricated, and the 

fact that it expands and contracts at a different rate from the 

building’s structural system, are important to understand when 

undertaking the restoration of a curtain wall system. 

Protecting and maintaining curtain walls and their components 

from the restoration period through appropriate surface treatments, such as cleaning, paint removal, and reapplication of 

protective coating system; and by making them watertight and 

ensuring that sealants and gaskets are in good condition. 

Failing to protect and maintain curtain wall components from the 

restoration period on a cyclical basis so that deterioration of the 

curtain wall results. 

Protecting ground-level curtain walls from the restoration period Leaving ground-level curtain walls from the restoration period 

from vandalism before work begins by covering them, while unprotected and subject to vandalism before work begins, thereby 

ensuring adequate ventilation, and by installing alarm systems also allowing the interior to be damaged if it can be accessed 

keyed into local protection agencies. through unprotected glazing. 

Protecting restoration-period curtain wall components when working on other features of the building. Failing to protect curtain wall components from the restoration 

period when working on other features of the building. 

Installing impact-resistant glazing, when required by safety codes 

or necessary for security, with color, transparency, and reflectivity 

as close as possible to the original in a curtain wall system from 

the restoration period so that it is compatible with the historic 

curtain walls and does not damage them or negatively impact 

their character. 

Installing impact-resistant glazing, when required by safety codes or 

necessary for security, that is not compatible with the historic curtain walls and damages them or negatively impacts their character. 

Evaluating the overall condition of the curtain wall system from Failing to undertake adequate measures to ensure the protection of 

the restoration period and its individual components to determine curtain wall features from the restoration period. 

whether more than protection and maintenance, such as repairs 

to curtain wall features, will be necessary. 

196 CURTAIN WALLS 
RESTORATION

CURTAIN WALLS 

RECOMMENDED NOT RECOMMENDED 

Repairing curtain walls from the restoration period by reinforc- Replacing an entire curtain wall from the restoration period when 

ing them or replacing deteriorated materials, including replacing repair of materials and limited replacement of deteriorated or missdeteriorated or missing sealants or gaskets, when necessary, to ing components are feasible. 

seal any gaps between system components. Repair may include 

the limited replacement in kind or with a compatible substitute 

material of those extensively deteriorated or missing components 

of curtain walls where there are surviving prototypes or when the 

replacement can be based on physical or historic documentation. 

The new work should match the old in material, design, scale, 

color, and finish. 

[12] This historic curtain wall features a 

distinctive variety of panel types which must be 

repaired or replicated in a restoration project if 

any are damaged or missing. 

CURTAIN WALLS 197
RESTORATION

CURTAIN WALLS 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire curtain wall from the restoration Removing a curtain wall feature from the restoration period that is 

period that is too deteriorated to repair (if the overall form and unrepairable and not replacing it, or replacing it with a new curtain 

detailing are still evident) using the physical evidence as a model wall feature that does not match. 

to reproduce the feature or when the replacement can be based 

on historic documentation. If using the same kind of material Using a substitute material for the replacement that does not 

is not feasible, then a compatible substitute material may be convey the same appearance of the surviving components of the 

considered. The new work may be unobtrusively dated to guide restoration-period curtain wall or that is physically incompatible. 

future research and treatment. 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic entrances and porches or their 

features that would be retained in Preservation and Rehabilitation treatments; and the replacement of missing curtain walls or their features from the 

restoration period using all new materials. 

Removing Existing Features from Other Historic Periods 

Removing curtain wall components from other historic periods. Failing to remove a curtain wall component from another period, 

thereby confusing the depiction of the building’s appearance from 

the restoration period 

Documenting curtain wall components dating from other periods Failing to document curtain wall components from other historic 

prior to their alteration or removal. If possible, selected examples periods that are removed from the building so that a valuable porof these components or materials should be stored for future tion of the historic record is lost. 

research. 

Recreating Missing Features from the Restoration Period 

Recreating a missing curtain wall component that existed during Constructing a curtain wall component that was part of the original 

the restoration period based on documentary and physical evi­ design for the building but was never actually built, or constructing 

dence. a feature which was thought to have existed during the restoration 

period but which cannot be documented. 

198 CURTAIN WALLS 
RESTORATION

 

STRUCTURAL SYSTEMS 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving structural systems and features from the restoration period. This includes the materials that 

comprise the structural system (i.e., wood, metal, and masonry), 

the type of system, and its features, such as posts and beams, 

trusses, summer beams, vigas, cast-iron or masonry columns, 

above-grade stone foundation walls, or load-bearing masonry 

walls. 

Altering visible features of structural systems from the restoration 

period. 

Failing to document structural systems from the restoration period, 

which may result in their loss. 

Overloading the structural system from the restoration period, or 

installing equipment or mechanical systems which could damage 

the structure. 

Replacing a load-bearing masonry wall from the restoration period 

that could be augmented and retained. 

Leaving known structural problems untreated, such as deflected 

beams, cracked and bowed walls, or racked structural members. 

Protecting and maintaining the structural system from the resto- Failing to protect and maintain exterior materials and features from 

ration period by keeping gutters and downspouts clear and roof- the restoration period on a cyclical basis so that deterioration of the 

ing in good repair; and by ensuring that wood structural members structural system results. 

are free from insect infestation. 

Using treatments or products that may retain moisture, which 

accelerates deterioration of structural members. 

Evaluating the overall condition of the structural system from Failing to undertake adequate measures to ensure the protection of 

the restoration period to determine whether more than protection the structural system from the restoration period. 

and maintenance, such as repairs to structural features, will be 

necessary. 

STRUCTURAL SYSTEMS 199
RESTORATION

STRUCTURAL SYSTEMS 

RECOMMENDED NOT RECOMMENDED 

Repairing structural systems from the restoration period by rein- Upgrading the building structurally in a manner that diminishes the 

forcing them by augmenting or upgrading individual components restoration-period character of the exterior (such as installing strapor features in a manner that is consistent with the restoration ping channels or removing a decorative masonry cornice) or that 

period. For example, weakened structural members, such as floor damages interior features or spaces. 

framing, can be paired with a new member, braced, or otherwise 

supplemented and reinforced. The new work should match the Replacing a component of the restoration-period structural system 

old in material, design, scale, color, and finish. when it could be repaired or augmented and retained. 

Installing a visible or exposed structural replacement feature that 

does not match the restoration-period feature (e.g., replacing an 

exposed wood summer beam with a steel beam). 

Using substitute material that does not equal the load-bearing 

capabilities of the restoration-period structural component; does not 

convey the same appearance of the restoration-period component, if 

it is visible; or is physically incompatible. 

Replacing in kind or with a compatible substitute material large 

portions or entire features of the structural system from the restoration period that are either extensively damaged or deteriorated 

or that are missing when there are surviving prototypes, such as 

cast-iron columns, trusses, or sections of load-bearing walls, or 

when the replacement can be based on historic documentation. 

Substitute material must be structurally sufficient, physically 

compatible with the rest of the system, and, where visible, must 

have the same form, design, and appearance as the restorationperiod feature. The new work may be unobtrusively dated to 

guide future research and treatment. 

200 STRUCTURAL SYSTEMS 
RESTORATION

STRUCTURAL SYSTEMS 

RECOMMENDED NOT RECOMMENDED 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing visible historic structural features that would 

be retained in Preservation and Rehabilitation treatments; and the replacement of missing visible structural features from the restoration period using all 

new materials. 

Removing Existing Features from Other Historic Periods 

Removing visually-intrusive structural features from other historic 

periods, such as a non-matching column. 

Failing to remove or alter a visually-intrusive structural feature from 

another period, thereby confusing the depiction of the building’s 

appearance from the restoration period. 

Documenting structural features dating from other periods prior 

to their alteration or removal. If possible, selected examples of 

these features or materials should be stored to facilitate future 

research. 

Recreating Missing Features from the Restoration Period 

Failing to document structural features from other historic periods 

that are removed from the building so that a valuable portion of the 

historic record is lost. 

Recreating a missing, visible structural feature that existed 

during the restoration period based on documentary and physical 

evidence; for example, duplicating a viga or cast-iron column. 

Constructing a visible structural feature that was part of the original 

design for the building but was never actually built, or constructing 

a feature which was thought to have existed during the restoration 

period but cannot be documented. 

STRUCTURAL SYSTEMS 201
RESTORATION

MECHANICAL SYSTEMS: 

HEATING, AIR CONDITIONING, ELECTRICAL, AND PLUMBING 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving visible features of mechani- Altering visible features of mechanical systems from the restoration 

cal systems from the restoration period, such as radiators, vents, period. 

fans, grilles, and plumbing and lighting fixtures. 

Failing to document visible features of mechanical systems from 

the restoration period, which may result in their loss. 

Protecting and maintaining functioning mechanical, plumbing, 

and electrical systems and their features from the restoration 

period through cyclical maintenance. 

Failing to protect and maintain functioning mechanical, plumbing, and electrical systems from the restoration period on a cyclical 

basis so that their deterioration results. 

Improving the energy efficiency of functioning mechanical 

systems to help reduce the need for a new system by installing 

storm windows and insulating attics and crawl spaces, if appropriate. 

Repairing functioning mechanical systems by augmenting or 

upgrading system components (such as installing new pipes and 

ducts), rewiring, or adding new compressors or boilers. 

Replacing a functioning mechanical system or its components when 

it could be upgraded and retained. 

Replacing in kind or with a compatible substitute material those 

extensively deteriorated or missing visible features of restorationperiod mechanical systems when there are prototypes, such as 

ceiling fans, radiators, grilles, or lighting fixtures. 

Installing a visible replacement feature that does not convey the 

same appearance as the restoration-period feature. 

Installing a new mechanical system, if required, in a manner that Installing a new mechanical system in a manner that the appearresults in the least alteration possible to the building’s appear­ ance of visible structural or interior features from the restoration 

ance from the restoration period. period is significantly changed, or the features are damaged or 

destroyed. 

Providing adequate structural support for new mechanical 

equipment. 

Failing to consider the weight and design of new mechanical equipment so that, as a result, restoration-period structural members or 

finished surfaces are weakened or cracked. 

202 MECHANICAL SYSTEMS 
RESTORATION

MECHANICAL SYSTEMS: 

HEATING, AIR CONDITIONING, ELECTRICAL, AND PLUMBING 

RECOMMENDED NOT RECOMMENDED 

Installing new mechanical and electrical systems and ducts, Installing ducts, pipes, and cables where they will obscure features 

pipes, and cables in closets, services areas, and wall cavities to from the restoration period. 

preserve the restoration-period character of the interior space. 

Concealing mechanical equipment in walls or ceilings in a manner 

that results in extensive loss or damage or otherwise obscures 

restoration-period building materials and features. 

Installing air conditioning units, if needed, in such a manner that 

features from the restoration period are not damaged or obscured, 

and so that excessive moisture is not generated that will accelerate deterioration of materials from the restoration period. 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing visible features of the mechanical system that 

would be retained in Preservation and Rehabilitation treatments; and the replacement of missing visible features of the mechanical system from the restoration period using all new materials.. 

Removing Existing Features from Other Historic Periods 

Removing mechanical systems and their visible features from 

other periods, such as a later elevator. 

Failing to remove or alter a visually-intrusive structural feature from 

another period, thereby confusing the depiction of the building’s 

appearance from the restoration period. 

Documenting mechanical systems and features from other Failing to document structural features from other historic periods 

periods prior to their alteration or removal. If possible, selected that are removed from the building so that a valuable portion of the 

examples of these features should be stored for future research. historic record is lost. 

Recreating Missing Features from the Restoration Period 

Recreating a missing feature of the mechanical system that Constructing a mechanical system or feature that was part of the 

existed during the restoration period based on documentary and original design for the building but was never actually built, or 

physical evidence; for example, duplicating a heating vent or constructing a feature which was thought to have existed during the 

lighting fixture. restoration period but cannot be documented. 

MECHANICAL SYSTEMS 203
RESTORATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving a floor plan and interior spaces, features, and finishes from the restoration period. 

Significant spatial characteristics include the size, configuration, 

proportion, and relationship of rooms and corridors; the relationship of features to spaces; and the spaces themselves, such as 

lobbies, lodge halls, entrance halls, parlors, theaters, auditoriums, gymnasiums, and industrial and commercial interiors. Color, 

texture, and pattern are important characteristics of features and 

finishes, which can include such elements as columns, plaster 

walls and ceilings, flooring, trim, fireplaces and mantels, paneling, light fixtures, hardware, decorative radiators, ornamental 

grilles and registers, windows, doors, and transoms; plaster, 

paint, wallpaper and wall coverings, and special finishes, such as 

marbleizing and graining; and utilitarian (painted or unpainted) 

features, including wood, metal, or concrete exposed columns, 

beams, and trusses and exposed load-bearing brick, concrete, 

and wood walls. 

Altering a floor plan, interior spaces (including individual rooms), 

features, or finishes from the restoration period. 

Failing to document interior spaces, features, and finishes from the 

restoration period, which may result in their loss. 

Applying paint, plaster, or other coatings to surfaces that have been 

unfinished historically, if the work cannot be documented. 

Changing the type of finish or the color, such as painting a historically-varnished wood feature from the restoration period, or 

removing paint from a historically-painted feature from the restoration period and staining and varnishing it, unless the work can be 

substantiated by physical or historic documentation. 

Stripping paint to bare wood rather than repainting, or not reapplying documented grained or marbled finishes from the restoration 

period to features, such as doors and paneling. 

Removing restoration-period interior features (such as mantels, 

woodwork, doors, windows, light fixtures, or radiators) or other decorative materials from the restoration period. 

Protecting and maintaining interior spaces, and materials, fea- Failing to protect interior features and finishes from the restoration 

tures, and finishes from the restoration period through appropri­ period when working on the interior. 

ate surface treatments, such as cleaning, paint removal, and 

reapplication of protective coating systems. 

Protecting interior features and finishes from the restoration Leaving the building unprotected with broken windows and open 

period against arson and vandalism before project work begins doorways before restoration begins so that the interior features and 

by covering broken windows and boarding open doorways, while finishes from the restoration period can be damaged by exposure to 

ensuring adequate ventilation, and by installing fire alarm sys- weather and vandalism. 

tems keyed into local protection agencies. 

204 INTERIOR SPACES, FEATURES, AND FINISHES 
RESTORATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Protecting interior features from the restoration period (such as 

a staircase, mantel, flooring, or decorative finishes) from damage 

during project work by covering them with plywood, heavy canvas, 

or plastic sheeting. 

Failing to protect interior features and finishes from the restoration 

period when working on the interior. 

Removing damaged or deteriorated paint and finishes from the 

restoration period only to the next sound layer, using the gentlest 

method possible, prior to repainting or refinishing using compatible paint or other coating systems based on historical documentation. 

Using potentially damaging methods, such as open-flame torches or 

abrasive techniques, to remove paint or other coatings. 

Removing paint that is firmly adhered to interior surfaces. 

Repainting with colors that are documented to the building’s 

restoration period. 

Using paint colors that are inappropriate to the building’s restoration period. 

[13] (a) In the 1990s the Missing Soldier’s Office—established by Clara 

Barton at the end of the Civil War—was discovered still extant on 

the third floor of a building in Washington, DC, that was slated for 

demolition. The office was restored to its historic appearance using 

physical and documentary evidence. The original numeral ‘9’ is still 

on the door to the office, and wall paper was reproduced from scraps 

found on the walls (b-d). 

INTERIOR SPACES, FEATURES, AND FINISHES 205
RESTORATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Using abrasive cleaning methods only on the interior of industrial Using abrasive methods anywhere but utilitarian and industrial 

or warehouse buildings with utilitarian, unplastered masonry interior spaces or when there are other methods that are less likely 

walls from the restoration period and where wood features are not to damage the surface of the material. 

finished, molded, beaded, or worked by hand. Low-pressure abrasive cleaning (e.g., sandblasting or other media blasting) should 

only be considered if test patches show no surface damage and 

after gentler methods have proven ineffective. 

Evaluating the overall condition of interior materials, features, 

and finishes from the restoration period to determine whether 

more than protection and maintenance, such as repairs to features and finishes, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

interior materials, features, and finishes from the restoration period. 

Repairing Interior features and finishes from the restoration Replacing an interior feature from the restoration period or a finish 

period by patching, splicing, consolidating, or otherwise reinforc­ when repair of materials and limited replacement of deteriorated or 

ing the materials using recognized preservation methods. Repair missing components are feasible. 

may include the limited replacement in kind or with a compatible 

substitute material of those extensively deteriorated or missing 

components of interior features when there are surviving prototypes (such as stairs, balustrades, wood paneling, columns, 

decorative wall finishes, or pressed-metal or plaster ceilings) 

or when the replacement can be based on physical or historic 

documentation. The new work should match the old in material, 

design, scale, color, and finish. 

206 INTERIOR SPACES, FEATURES, AND FINISHES 
207

RESTORATION

[14] When the 1931 Fox Theater in 

Spokane, WA, was rehabilitated 

as a performing arts center, the 

auditorium was restored to its 

original Art Deco splendor. 

INTERIOR SPACES, FEATURES, AND FINISHES 
RESTORATION

INTERIOR SPACES, FEATURES, AND FINISHES 

RECOMMENDED NOT RECOMMENDED 

Replacing in kind an entire interior feature from the restoration Removing a feature or finish from the restoration period that is 

period that is too deteriorated to repair (if the overall form and unrepairable and not replacing it, or replacing it with a new feature 

detailing are still evident) using the physical evidence as a model or finish that does not match. 

to reproduce the feature or when the replacement can be based 

on historic documentation. Examples could include wainscoting, Using a substitute material for the replacement that does not 

window and door surrounds, or interior stairs. If using the same convey the same appearance of the surviving components of the 

kind of material is not feasible, then a compatible substitute restoration-period interior feature or finish or that is physically 

material may be considered. The new work may be unobtrusively incompatible. 

dated to guide future research and treatment. 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic interior spaces, features, and finishes 

that would be retained in Preservation and Rehabilitation treatments; and the replacement of missing interior spaces, features, and finishes from the restoration period using all new materials. 

Removing Existing Features from Other Historic Periods 

Removing or altering interior spaces, features, or finishes from 

other historic periods, such as a dropped ceiling or wood paneling. 

Failing to remove an interior space, feature, or finish from another 

historic period, thereby confusing the depiction of the building’s 

appearance from the restoration period. 

Documenting materials and features dating from other periods Failing to document interior spaces, features, and finishes from 

prior to their alteration or removal. If possible, selected exam- other periods that are removed from the building so that a valuable 

ples of these features or materials should be stored for future portion of the historic record is lost. 

research. 

Recreating Missing Features from the Restoration Period 

Recreating an interior space or a missing feature or finish from Creating an interior space, adding a feature, or applying a finish 

the restoration period based on documentary and physical evi­ that was part of the original design for the building but was never 

dence; for example, duplicating a mantel or a staircase. actually built, or adding a feature which was thought to have existed 

during the restoration period but cannot be documented. 

208 INTERIOR SPACES, FEATURES, AND FINISHES 
RESTORATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving features of the building Altering buildings and their features or site features from the restosite from the restoration period. Site features may include walls, ration period. 

fences, or steps; circulation systems, such as walks, paths, or 

roads; vegetation, such as trees, shrubs, grass, orchards, hedges, Failing to document building and site features from the restoration 

windbreaks, or gardens; landforms, such as hills, terracing, or period, which may result in their loss. 

berms; furnishings and fixtures, such as light posts or benches; 

decorative elements, such as sculpture, statuary, or monuments; 

water features, such as fountains, streams, pools, lakes, irrigation 

ditches; and subsurface archeological resources, other cultural or 

religious features, or burial grounds which are also important to 

the restoration period of the site. 

Reestablishing the relationship between buildings and the landscape on the site that existed during the restoration period. Retaining non-restoration period buildings or landscape features on 

the site, thereby confusing the depiction of the restoration-period 

appearance of the site. 

Protecting and maintaining buildings and site features from the Failing to ensure that site drainage is adequate so that buildrestoration period by providing proper drainage to ensure that ings and site features from the restoration period are damaged or 

water does not erode foundation walls, drain toward a building, or destroyed. Or, alternatively, changing the site grading so that water 

damage or erode the landscape. does not drain properly. 

Minimizing disturbance of the terrain around buildings or else- Using heavy machinery or equipment in areas where it may disturb 

where on the site, thereby reducing the possibility of destroying or damage important landscape features from the restoration period 

or damaging important landscape features from the restoration or archeological resources, other cultural or religious features, or 

period or archeological resources, other cultural or religious fea­ burial grounds. 

tures, or burial grounds. 

BUILDING SITE 209
210

RESTORATION

[15] (a) Cherry Hill House and Farm 

(c. 1845) in Falls Church, VA, was the site of 

encampments during the Civil War. Outbuildings 

on the property, such as the corn crib (b) in the 

foreground which was the source of provisions 

for the soldiers, are important in interpreting its 

role during the war. 

BUILDING SITE 
RESTORATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Surveying and documenting areas of the site where the terrain Failing to survey the building site prior to beginning restoration 

will be altered during restoration work to determine the poten­ work, which can result in damaging or destroying landscape featial impact to important landscape features from the restoration tures from the restoration period, or archeological resources, other 

period or archeological resources, other cultural or religious cultural or religious features, or burial grounds. 

features, or burial grounds from the restoration period. 

Protecting (e.g., preserving in place) important site features, 

archeological resources, other cultural or religious features, or 

burial grounds. 

Failing to protect site features from the restoration period, or 

archeological resources, other cultural or religious features, or burial 

grounds when working on the site. 

Planning and carrying out any necessary investigation before restoration of the site begins, using professional archeologists and 

methods, when preservation in place is not feasible. 

Allowing unqualified personnel to perform data recovery on archeological resources, which can result in damage or loss of important 

archeological material. 

Preserving important landscape features from the restoration 

period through regularly-scheduled site maintenance of historic 

plant material. 

Allowing important landscape features from the restoration period 

to be lost or damaged due to lack of site maintenance. 

Protecting the building site and landscape features from the 

restoration period against arson and vandalism before restoration 

work begins by erecting temporary fencing and by installing alarm 

systems keyed into local protection agencies. 

Leaving the property unprotected and subject to vandalism before 

work begins so that the building site and landscape features from 

the restoration period, or archeological resources, other cultural or 

religious features, or burial grounds can be damaged or destroyed. 

Removing site features from the restoration period, such as fencing, 

paths or walkways, masonry balustrades, or plant material. 

Installing protective fencing, bollards, and stanchions on a build- Installing protective fencing, bollards, and stanchions on a building site, when necessary for security, that are as unobtrusive as ing site, when necessary for security, without taking into considerpossible. ation their location and visibility so that they negatively impact the 

restoration-period character of the site. 

BUILDING SITE 211
RESTORATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Providing continued protection and maintenance of buildings and 

landscape features from the restoration-period of the site through 

appropriate grounds and landscape management. 

Failing to protect and maintain materials and features from the 

restoration period on a cyclical basis so that deterioration of the site 

results. 

Protecting buildings and site features from the restoration period 

when working on the site. 

Failing to protect buildings and landscape features from the restoration period when working on the site or failing to repair damaged or 

deteriorated site features. 

Evaluating the overall condition of materials and features from the 

restoration period to determine whether more than protection and 

maintenance, such as repairs to site features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

site features from the restoration period. 

Repairing site features from the restoration period which have 

been damaged, are deteriorated, or have missing components 

to reestablish the whole feature and to ensure retention of the 

integrity of the historic materials. Repair may include limited 

replacement in kind or with a compatible substitute material of 

those extensively deteriorated or missing components of site features when there are surviving prototypes, such as paving, railing, 

or individual plants within a group (e.g., a hedge), or when the 

replacement can be based on physical or historic documentation. 

Replacing an entire site feature from the restoration period (such 

as a fence, walkway, or drive) when repair of materials and limited 

replacement of deteriorated or missing components are feasible. 

Replacing in kind an entire restoration-period feature of the site 

that is too deteriorated to repair (if the overall form and detailing are still evident) using the physical evidence as a model to 

reproduce the feature or when the replacement can be based on 

historic documentation. Examples could include a walkway or 

fountain, a land form or plant materials. If using the same kind 

of material is not feasible, then a compatible substitute material 

may be used. The new work may be unobtrusively dated to guide 

future research and treatment. 

Removing a site feature from the restoration period that is unrepairable and not replacing it, or replacing it with a new feature that 

does not match. 

Using a substitute material for the replacement that does not 

convey the same appearance of the surviving site feature from the 

restoration period or that is physically incompatible. 

Adding conjectural landscape features to the site (such as period 

reproduction light fixtures, fences, fountains, or vegetation) that 

cannot be documented, thereby confusing the depiction of the 

restoration-period appearance of the building site. 

212 BUILDING SITE 
RESTORATION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing visible features of the building site that would 

be retained in Preservation and Rehabilitation treatments; and the replacement of missing visible features of the mechanical system from the restoration 

period using all new materials. 

Removing Existing Features from Other Historic Periods 

Removing site features from other historic periods, such as an 

outbuilding, paved road, or overgrown trees. 

Failing to remove a site feature from another historic period, 

thereby confusing the depiction of the site’s appearance from the 

restoration period. 

Documenting features of the building site dating from other periods prior to their removal. 

Recreating Missing Features from the Restoration Period 

Failing to document site features from other periods that are 

removed during restoration so that a valuable portion of the historic 

record is lost. 

Recreating a missing site feature from the restoration period 

based on documentary and physical evidence; for example, duplicating a no-longer extant terrace, gazebo, fencing, or a hedge. 

Constructing a feature of the building or site that was part of the 

original design but was never actually built, or constructing a feature which was thought to have existed during the restoration period 

but cannot be documented. 

[16] Archeological 

investigation of the 

property was undertaken 

to ensure accuracy of the 

restoration of Montpelier. 

Photo: Courtesy of The 

Montpelier Foundation. 

BUILDING SITE 213
RESTORATION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

Identifying, retaining, and preserving building and landscape 

features from the restoration period in the setting. These features 

can include circulation systems, such as roads and streets; furnishings and fixtures, such as light posts or benches; vegetation, 

gardens, and yards; adjacent open space, such as fields, parks, 

commons, or woodlands; and important views or visual relationships. 

Altering restoration-period building and landscape features in the 

setting. 

Failing to document restoration-period buildings and landscape 

features in the setting, which may result in their loss. 

Retaining or reestablishing the relationship between buildings 

and landscape features in the setting that existed during the 

restoration period. 

Retaining non-restoration period buildings or landscape features 

in the setting, thereby confusing the depiction of the restorationperiod appearance of the setting. 

[17 a-b] The cobblestone street, brick
 

sidewalks, and stone stoops of these
 

houses are important restoration-


period features of the late 18ththrough the 19th-century restoration
 

period of this historic district.
 

(a) 

214 SETTING (DISTRICT / NEIGHBORHOOD) 
RESTORATION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

Protecting and maintaining features from the restoration period 

in the setting through regularly-scheduled maintenance and 

grounds and landscape management. 

Failing to protect and maintain materials in the setting on a cyclical basis so that deterioration of buildings and landscape features 

results. 

Removing restoration-period building or landscape features in the 

setting, such as porches, fencing, walkways, or plant material. 

Installing protective fencing, bollards, and stanchions in a setting, when necessary for security, that are as unobtrusive as 

possible. 

Installing protective fencing, bollards, and stanchions in a setting, 

when necessary for security, without taking into consideration their 

location and visibility so that they negatively impact the historic 

character of the setting. 

(b) 

SETTING (DISTRICT / NEIGHBORHOOD) 215
RESTORATION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

Protecting buildings and landscape features from the restoration 

period when undertaking work in the setting. 

Failing to protect buildings and landscape features from the restoration period when working in the setting. 

Evaluating the overall condition of restoration-period materials and features in the setting to determine whether more than 

protection and maintenance, such as repairs to materials and 

features, will be necessary. 

Failing to undertake adequate measures to ensure the protection of 

materials and features in the setting from the restoration period. 

Repairing restoration-period features in the setting by reinforcing 

the historic materials. Repair may include the replacement in 

kind or with a compatible substitute material of those extensively 

deteriorated or missing components of features from the restoration period when there are surviving prototypes, such as porch 

balustrades, paving materials, or trees. 

Replacing an entire building or landscape feature from the restoration period in the setting when repair of materials and limited 

replacement of deteriorated or missing components are feasible. 

Replacing in kind an entire restoration-period building or land- Removing a restoration-period feature of the building or landscape 

scape feature in the setting that is too deteriorated to repair (if in the setting that is unrepairable and not replacing it, or replacing 

the overall form and detailing are still evident) using the physi­ it with a new feature that does not match. 

cal evidence as a model to reproduce the feature or when the 

replacement can be based on historic documentation. If using Using a substitute material for the replacement that does not 

the same kind of material is not feasible, then a compatible sub- convey the same appearance of the surviving restoration-period 

stitute material may be considered. The new work may be dated building or landscape feature in the setting or that is physically or 

to guide future research and treatment. ecologically incompatible. 

216 SETTING (DISTRICT / NEIGHBORHOOD) 
RESTORATION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic features of the setting that would be 

retained in Preservation and Rehabilitation treatments; and the replacement of missing restoration-period features of the setting using all new materials. 

Removing Existing Features from Other Historic Periods 

Removing features of the building or landscape in the setting 

from other historic periods, such as a road, sidewalk, or fence. 

Failing to remove a feature of the building or landscape in the 

setting from another period, thereby confusing the depiction of the 

setting’s appearance from the restoration period. 

Documenting features of the building or landscape in the setting 

dating from other periods prior to their removal. 

Recreating Missing Features from the Restoration Period 

Failing to document features of the building or landscape features 

in the setting from other periods that are removed during restoration 

so that a valuable portion of the historic record is lost. 

Recreating a missing feature of the building or landscape in 

the setting that existed during the restoration period based on 

documentary and physical evidence; for example, duplicating a 

non-longer extant path or park bench. 

Constructing a feature of the building or landscape that was part of 

the original design for the setting but was never actually built, or 

constructing a feature which was thought to have existed during the 

restoration period but cannot be documented. 

SETTING (DISTRICT / NEIGHBORHOOD) 217
RESTORATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Sensitive solutions to meeting accessibility and life-safety code requirements are an important part of protecting the restoration-period of the building and 

site. Thus, work that must be done to meet use-specific code requirements in the treatment Restoration must also be assessed for its potential impact on the 

restoration-period of the historic building and site. 

Accessibility 

Identifying the restoration-period exterior features, interior Undertaking accessibility code-required alterations before identifyspaces, features, and finishes, and features of the site and set­ ing the exterior features, interior spaces, features, and finishes, 

ting which may be affected by accessibility code-required work. and features of the site and setting from the restoration period and, 

therefore, must be preserved. 

Complying with barrier-free access requirements in such a Altering, damaging, or destroying the exterior features, interior 

manner that the restoration-period exterior features, interior spaces, features, and finishes, or features of the site and setting 

spaces, features, and finishes, and features of the site and set- from the restoration period while complying with accessibility 

ting are preserved or impacted as little as possible. requirements. 

Working with specialists in accessibility and historic preservation Making changes to historic buildings and their sites without first 

to determine the most sensitive solutions to comply with access consulting with specialists in accessibility and historic preservation 

requirements in a restoration project. to determine the most appropriate solutions to comply with accessibility requirements in a manner that will preserve the character of 

the restoration period. 

Providing barrier-free access that promotes independence for the 

user while preserving significant features from the restoration 

period. 

Making access modifications that do not provide independent, safe 

access while preserving restoration-period features. 

Finding solutions to meet accessibility requirements that minimize the impact of any necessary alteration on the restoration 

period of the building, its site, and setting, such as compatible 

ramps, paths, and lifts. 

Making modifications for accessibility without considering the 

impact on the restoration period of the building, its site, or setting. 

Using relevant sections of existing codes regarding accessibility for historic buildings that provide alternative means of code 

compliance when code-required work would otherwise negatively 

impact the restoration-period character of the property. 

218 CODE-REQUIRED WORK | ACCESSIBILITY 
RESTORATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Minimizing the visual impact of accessibility ramps by installing them on secondary elevations when it does not compromise 

accessibility or by screening them with plantings. 

Adding a gradual slope or grade to the sidewalk, if appropriate, to 

access the entrance rather than installing a ramp that would be 

more intrusive to the historic character of the restoration period 

of the building and the district. 

[18 a-b] The historic Chapel of Our Lady in Cold Spring, NY, is 

situated on a rocky promontory overlooking the Hudson River. 

Installing an accessible ramp would greatly compromise the 

character of the building and the site. However, an audio-visual 

program available in a separate building—–located where it 

would not impact the character of the site, such as this small 

pavilion at the rear of the property—–could provide visitors 

otherwise unable to access the Chapel an opportunity to 

experience the site. 

CODE-REQUIRED WORK | ACCESSIBILITY 219
RESTORATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Installing a lift as inconspicuously as possible when it is necessary to locate it on a primary elevation of the historic building. 

Considering placing accessible facilities needed for visitors to the Installing accessible facilities inside or on the exterior of the hisrestored property (e.g., restrooms) in a separate building, such toric building that are incompatible with the character of the restoas a visitor center, that is located away from the historic struc­ ration period or would damage or destroy character-defining spaces, 

ture rather than in the historic building if their installation would features, or finishes from the restoration period. 

negatively impact character-defining spaces, features, or finishes 

from the restoration period. 

Devising non-permanent or temporary adaptive treatments that 

meet accessibility requirements to preserve the restoration-period 

character of the building, its site, and setting. 

Developing and providing virtual tours to help interpret the 

restored property when it is not feasible or it is physically impossible to make the building or its site accessible without damaging 

or obscuring character-defining building and landscape features 

in the setting from the restoration period. 

LIFE SAFETY 

Identifying the restoration-period exterior features, interior Undertaking life-safety code-required alterations before identifying 

spaces, features, and finishes, and features of the site and set- the exterior features, interior spaces, features, and finishes, and 

ting which may be affected by life-safety code-required work. features of the site and setting from the restoration period and, 

therefore, must be preserved. 

Complying with life-safety codes (including requirements for Altering, damaging, or destroying the restoration-period exterior 

impact-resistant glazing, security, and seismic retrofit) in such features, interior spaces, features, and finishes, or features of the 

a manner that the restoration-period exterior features, interior site and setting from the restoration period while making modificaspaces, features, and finishes, and features of the site and set­ tions to a building, its site, or setting to comply with life-safety code 

ting are preserved or impacted as little as possible. requirements. 

Removing building materials from the restoration period only Removing building materials from the restoration period without 

after testing has been conducted to identify hazardous materials, testing first to identify any hazardous materials, or using potentiallyand using only the least damaging abatement methods. damaging methods of abatement without considering less-invasive 

methods of abatement. 

220 CODE-REQUIRED WORK | ACCESSIBILITY AND LIFE SAFETY 
RESTORATION

CODE-REQUIRED WORK 

RECOMMENDED NOT RECOMMENDED 

Providing workers with appropriate personal equipment for protection from hazards on the worksite. Removing hazardous or toxic materials without regard for workers’ health and safety or environmentally-sensitive disposal of the 

materials. 

Working with code officials and historic preservation specialists Making life-safety code-required changes to the building without 

to investigate systems, methods, or devices to make the building consulting code officials and historic preservation specialists, with 

compliant with life-safety codes to ensure that necessary altera­ the result that alterations negatively impact the restoration-period 

tions will be compatible with the restoration-period character of character of the building. 

the building. 

Using relevant sections of existing codes regarding life safety for 

historic buildings that provide alternative means of compliance 

when life-safety code-required work would otherwise negatively 

impact the restoration-period character of the building. 

Upgrading restoration-period stairways and elevators to meet 

life-safety codes so that they are not damaged or their historic 

character is not negatively impacted. 

Damaging or making inappropriate alterations to historic stairways 

or elevators or to adjacent features, spaces, or finishes from the restoration period while complying with life-safety code requirements. 

Installing sensitively-designed fire-suppression systems, such as 

sprinklers, so that historic features and finishes from the restoration period are preserved. 

Covering wood features from the restoration period with fire-retardant sheathing, which results in altering their appearance. 

Applying fire-retardant coatings when appropriate, such as 

intumescent paint, to protect steel structural systems from the 

restoration period. 

Using fire-retardant coatings if they will damage or obscure character-defining features from the restoration period. 

CODE-REQUIRED WORK | LIFE SAFETY 221
RESTORATION

RESILIENCE TO NATURAL HAZARDS 

RECOMMENDED NOT RECOMMENDED 

Resilience to natural hazards should be addressed as part of a Restoration project. A historic building may have existing characteristics or features from the 

restoration period that help address or minimize the impacts of natural hazards. These should be used to best advantage and should be taken into consideration early in the planning stages of a restoration project before proposing any additional treatments. When new adaptive treatments are needed they should 

be carried out in a manner that will have the least impact on the restoration-period character of the building, its site, and setting. 

Identifying the vulnerabilities of the restoration-period property to 

the impacts of natural hazards (such as wildfires, hurricanes, or 

tornadoes) using the most current climate information and data 

available. 

Failing to identify and periodically reevaluate the potential vulnerability of the restoration-period building, its site, and setting to the 

impacts of natural hazards. 

Assessing the potential impacts of known vulnerabilities on restoration-period features of the building, its site, and setting; and 

reevaluating and reassessing potential impacts on a regular basis. 

[19] The 1951 Mies van der Rohe-designed 

Farnsworth House, Plano, IL, was built 

close to the Fox River, which is increasingly 

prone to floods. To preserve the house in 

its original location, historic preservation 

architects and engineers continue to 

explore ways to protect it from the flooding, 

including a possible system that would 

lift the house above the flood waters and 

lower it back to the ground. Photo: Courtesy 

Farnsworth, A Site of the National Trust for 

Historic Preservation. 

222 RESILIENCE TO NATURAL HAZARDS 
RESTORATION

RESILIENCE TO NATURAL HAZARDS 

RECOMMENDED NOT RECOMMENDED 

Documenting the restoration-period character of the property as 

a record and guide for future repair work, should it be necessary, 

and storing the documentation in a weatherproof location. 

Failing to document the restoration-period character of the property 

with the result that such information is not available in the future to 

guide repair or reconstruction work, should it be necessary. 

Ensuring that historic resources inventories and maps are accurate, up to date, and accessible in an emergency. 

Maintaining the restoration-period building, its site, and setting 

in good repair, and regularly monitoring their condition. 

Failing to regularly monitor and maintain the restoration-period 

property and the building systems in good repair. 

Using and maintaining existing characteristics and features of 

the restoration-period building, its site, setting, and larger environment (such as shutters for storm protection or a site wall that 

keeps out flood waters) that may help to avoid or minimize the 

impacts of natural hazards. 

Allowing loss, damage, or destruction to occur to the restorationperiod building, its site, or setting by failing to evaluate potential 

future impacts of natural hazards or to plan and implement adaptive measures, when necessary to address possible threats. 

Undertaking work to prevent or minimize the loss, damage, or Carrying out adaptive measures intended to address the impacts 

destruction of the historic property while retaining and preserving of natural hazards that are unnecessarily invasive or will otherwise 

significant features and the overall restoration-period character of adversely impact the restoration-period character of the building, its 

the building, its site, and setting. site, or setting. 

Ensuring that, when planning work to adapt for natural hazards, 

all feasible alternatives are considered, and that the options 

requiring the least alteration to the restoration-period character of 

the property are considered first. 

Implementing local and regional traditions (such as elevating 

residential buildings at risk of flooding or reducing flammable 

vegetation around structures in fire-prone areas) for adapting buildings and sites in response to specific natural hazards which would 

negatively impact the restoration-period character of the property. 

Using special exemptions and variances when adaptive treatments to protect buildings from known hazards would otherwise 

negatively impact the restoration-period character of the building, 

its site, or setting. 

RESILIENCE TO NATURAL HAZARDS 223
224

RESTORATION

Sustainability 

Sustainability should be addressed as part of a Restoration project. 

Existing energy-efficient features from the restoration period should 

be retained and restored while those that are no longer extant but 

which were important in defining the restoration-period character 

of the building should be recreated. New sustainability treatments 

should only be undertaken if they will not impact the restorationperiod character of the building. 

The topic of sustainability is addressed in detail in The Secretary of 

the Interior’s Standards for Rehabilitation & Illustrated Guidelines on 

Sustainability for Rehabilitating Historic Buildings. Although specifically developed for the treatment Rehabilitation, the Sustainability 

Guidelines can be used to help guide the other treatments 

SUSTAINABILITY 
RECONSTRUCTION

STANDARDS FOR RECONSTRUCTION & GUIDELINES 

FOR RECONSTRUCTING HISTORIC BUILDINGS 

Reconstruction
 

Reconstruction is defined as the act or process of depicting, by 

means of new construction, the form, features, and detailing of 

a non-surviving site, landscape, building, structure, or object for 

the purpose of replicating its appearance at a specific period of 

time and in its historic location. 

225
RECONSTRUCTION

226

Standards for Reconstruction 

1.	 Reconstruction will be used to depict vanished or non-surviving portions of a property 

when documentary and physical evidence is available to permit accurate reconstruction 

with minimal conjecture and such reconstruction is essential to the public understanding 

of the property. 

2.	 Reconstruction of a landscape, building, structure or object in its historic location will be 

preceded by a thorough archeological investigation to identify and evaluate those features 

and artifacts which are essential to an accurate reconstruction. If such resources must be 

disturbed, mitigation measures will be undertaken. 

3.	 Reconstruction will include measures to preserve any remaining historic materials, 

features, and spatial relationships. 

4.	 Reconstruction will be based on the accurate duplication of historic features and 

elements substantiated by documentary or physical evidence rather than on conjectural 

designs or the availability of different features from other historic properties. A 

reconstructed property will re-create the appearance of the non-surviving historic 

property in materials, design, color and texture. 

5.	 A reconstruction will be clearly identified as a contemporary re-creation. 

6.	 Designs that were never executed historically will not be constructed. 
GUIDELINES FOR RECONSTRUCTING HISTORIC BUILDINGS 

INTRODUCTION 

Reconstruction is different from the other treatments in that it is 

undertaken when there are often no visible historic materials extant 

or only a foundation remains. Whereas the treatment Restoration provides guidance on restoring historic building features, the 

Standards for Reconstruction and Guidelines for Reconstructing Historic Buildings should be followed when it is necessary 

to recreate a non-surviving building using new material. But, like 

restoration, reconstruction also involves recreating a historic building which appears as it did at a particular—and at its most significant—time in its history. Because of the potential for historical error 

in the absence of sound physical evidence, this treatment can be 

justified only rarely and, thus, is the least frequently undertaken of 

the four treatments. Reconstructing a historic building should only 

be considered when there is accurate documentation on which to 

base it. When only the appearance of the exterior of the building can 

be documented, it may be appropriate to reconstruct the exterior 

while designing a very simple, plain interior that does not attempt 

to appear historic or historically accurate. Signage and interpretative aids should make it clear to visitors that only the exterior of the 

building is a true reconstruction. Extant historic surface and subsurface materials should also be preserved. Finally, the reconstructed 

building must be clearly identified as a contemporary recreation. 

Research and Document Historical 

Significance 

The guidance for the treatment Reconstruction begins with 

researching and documenting the building’s historical significance to 

determine whether its recreation is essential to the public understanding of the property. In some instances, reconstruction may not 

be necessary if there is a historic building still existing on the site or 

in a setting that can explain the history of the property. Justifying a 

reconstruction requires detailed physical and documentary evidence 

to minimize or eliminate conjecture and to ensure that the reconstruction is as accurate as possible. Only one period of significance 

is generally identified; a building—as it evolved—is rarely recreated. 

If research does not provide adequate documentation for an accurate reconstruction, other interpretive methods should be considered, such as an explanatory marker. 

Investigate Archeological Resources 

Investigating archeological resources is the next area of guidance 

in the treatment Reconstruction. The purpose of archeological 

research is to identify any remaining features of the building, site, 

and setting that are essential to an accurate recreation and must be 

reconstructed. Archeological resources that are not essential to the 

reconstruction should be left in place. The archeological findings, 

together with archival documentation, should be used to replicate 

the design, materials, and plan of the historic building. 

INTRODUCTION 227
RECONSTRUCTION

228

Identify, Protect, and Preserve Extant 

Historic Features 

Closely aligned with archeological research, recommendations are 

given for identifying, protecting, and preserving extant features of the 

historic building. It is never appropriate to base a Reconstruction

upon conjectural designs or on features from other buildings. Any 

remaining historic materials and features should be retained and 

incorporated into the reconstruction when feasible. Both the historic 

and new materials should be documented to assist in interpretation. 

Reconstruct Non-Surviving Building and Site 

After the research and documentation phases, guidance is given 

for Reconstruction work itself. Exterior and interior features are 

addressed in general, always emphasizing the need for an accurate 

depiction (i.e., careful duplication of the appearance of historic 

materials and features for interpretative purposes). While the use 

of traditional materials and finishes is always preferred, in some 

instances substitute materials may be used if they are able to convey 

the same appearance. Where non-visible features of the building 

are concerned, such as interior structural systems, contemporary 

materials and technology may be used. Recreating the features of the 

building site or setting based on archeological findings should also 

be an integral part of project work. 

Accessibility and Life Safety, Natural Hazards, 

and Sustainability 

Whereas preservation, rehabilitation, and restoration treatments 

usually necessitate retrofitting to meet code requirements and to 

address other issues (including natural hazards and sustainability), 

in this treatment it is assumed that the Reconstructed building 

will be essentially new construction. Thus, code-required work, 

treatments to reduce the potential impact of natural hazards, and 

ensuring that the reconstructed building is as sustainable as possible 

should be considered during the design phase—when appropriate to 

the particular Reconstruction project—so as not to negatively impact 

or detract from the reconstructed appearance of the building, its site, 

and setting. The fact that the non-surviving building was located in 

a floodplain or another area especially vulnerable to the impact of 

natural hazards is crucial to consider when determining whether the 

building should be reconstructed. 

The topic of sustainability is addressed in detail in The Secretary of 

the Interior’s Standards for Rehabilitation & Illustrated Guidelines on 

Sustainability for Rehabilitating Historic Buildings. Although specifically 

developed for the treatment Rehabilitation, the Guidelines can be 

used to help guide the other treatments. 

Reconstruction as a Treatment. When a contemporary depiction is 

required to understand and interpret a property’s historic value (including 

the re-creation of missing components in a historic district or site); when 

no other property with the same associative value has survived; and when 

sufficient historical documentation exists to ensure an accurate reproduction, Reconstruction may be considered as a treatment. Prior to undertaking work, a documentation plan for Reconstruction should be developed. 

INTRODUCTION 
[1 a-b] Tyron Palace, New 

Bern, NC, was designed 

by John Hawks in 1767 

for Governor William 

Tyron. It was completed 

in 1770, but destroyed by 

fire in 1798. The palace 

was reconstructed 

in 1959 based on the 

original plans, and on 

its original foundation, 

which was found 5 feet 

below the street, with the 

help of the 1767 drawing. 

Photo: Courtesy Tyron 

Palace, New Bern, NC. 

Drawing: Courtesy of the 

State Archives of North 

Carolina. 

INTRODUCTION 229
RECONSTRUCTION

230

[2] The Saugus Iron 

Works, Saugus, MA, a 

National Historic Site, 

was active from 1646 

to about 1670 and was 

the first integrated 

iron works in North 

America. The forge and 

mill (shown here) are 

part of the site which 

was reconstructed 

based on archeological 

research and historic 

documents and opened 

in 1954. Photo: Daderot 

at the English language 

Wikipedia. 

OVERVIEW 
OVERVIEW 

RECOMMENDED NOT RECOMMENDED 

Researching and documenting the property’s historical signifi- Undertaking a reconstruction based on insufficient research so that, 

cance, focusing on documentary and physical evidence which is as a result, a historically inaccurate building is created. 

needed to justify reconstruction of the non-surviving building. 

Reconstructing a building unnecessarily when an existing building adequately reflects or explains the history of the property, the 

historical event, or has the same associative value. 

Executing a design for a building that was never constructed. 

Investigating archeological resources to identify and evaluate 

those features and artifacts which are essential to the design and 

plan of the building. 

Failing to identify and evaluate archeological material prior to 

reconstruction, or destroying extant historic material not relevant to 

the reconstruction but which should be preserved in place. 

Minimizing disturbance of the terrain around buildings or Using heavy machinery or equipment in areas where it may disturb 

elsewhere on the site, thereby reducing the possibility of destroy- or damage important landscape features, archeological resources, 

ing or damaging important landscape features, archeological cultural or religious features, or burial grounds. 

resources, other cultural or religious features, or burial grounds. 

Identifying, retaining, and preserving extant historic features of Beginning reconstruction work without first conducting a detailed 

the building, site, and setting, such as remnants of a foundation, site investigation to physically substantiate the documentary evichimney, or walkway. dence. 

Basing a reconstruction on conjectural designs or on features from 

other historic buildings. 

[3] The Cathedral of Saint Michael the Archangel, 

built in the early 1840s in Sitka, AK, was devastated 

by fire in 1966. It was reconstructed using measured 

drawings done in 1961 by the Historic American 

Buildings Survey (HABS). While the original cathedral 

was built of logs covered on the exterior with wood 

siding, its replacement is a fire-resistant structure 

with concrete and steel walls that replicates the 

historic building’s appearance. Photo: Barek at 

Wikimedia Commons. 

OVERVIEW 231
RECONSTRUCTION

BUILDING EXTERIOR 

RECOMMENDED NOT RECOMMENDED 

Reconstructing a non-surviving building to depict the docu- Reconstructing features that cannot be documented historically or 

mented historic appearance. Although the use of the original for which existing documentation is inadequate. 

building materials (such as masonry, wood, and architectural 

metals) is preferable, substitute materials may be used as long Using substitute materials that do not convey the appearance of the 

as they recreate the historic appearance. historic building. 

Recreating the documented design of exterior features, such as Omitting a documented exterior feature, or rebuilding a feature but 

the roof form and its coverings, architectural detailing, windows, altering its historic design. 

entrances and porches, steps and doors, and their historic spatial 

relationships and proportions. Using inappropriate designs or materials that do not convey the 

historic appearance. 

Reproducing the appearance of historic paint colors and finishes 

based on documentary and physical evidence. 

Using paint colors that cannot be documented through research 

and investigation or using other undocumented finishes. 

Installing exterior electrical and telephone cables underground 

or in the least obtrusive location possible, unless they can be 

documented as having been aboveground historically. 

Attaching exterior electrical and telephone cables to the principal 

elevations of the reconstructed building, unless they can be documented as having been there historically. 

Using signage to identify the building as a contemporary 

recreation. 

Failing to explain that the building is a reconstruction, thereby 

confusing the public’s understanding of the property. 

232 BUILDING EXTERIOR 
[4] The McLean House, 

where Robert E. Lee 

surrendered to Ulysses 

S. Grant, is located 

on the site of the 

battlefield—now part of 

Appomattox Courthouse 

National Historical 

Monument (VA). Several 

years after the end of 

the Civil War, measured 

drawings were made 

of the house before it 

was dismantled to be 

moved to Washington, 

DC, where it was to 

be reconstructed as 

a tourist attraction. 

This scheme never 

came to fruition, and 

the dismantled pieces 

gradually disappeared. 

The house was 

accurately reconstructed 

in 1949 on the original 

site based on the 

measured drawings. 

BUILDING EXTERIOR 233
RECONSTRUCTION

BUILDING INTERIOR 

RECOMMENDED NOT RECOMMENDED 

Recreating the appearance of visible features of the historic Changing the documented appearance of visible features of the 

structural system, such as posts and beams, trusses, summer structural system. 

beams, vigas, cast-iron columns, above-grade masonry foundations, or load-bearing brick or stone walls. Contemporary methods 

and materials may be used for the actual structural system of the 

reconstructed building. 

Recreating the historic floor plan and interior spaces, including Altering the documented historic floor plan, or relocating an 

the size, configuration, proportion, and relationship of rooms and important interior feature, such as a staircase, so that the historic 

corridors; the relationship of features to spaces; and the spaces relationship between the feature and the space is inaccurately 

themselves. depicted. 

Reconstructing the historic appearance of the interior without accurate documentation. 

Duplicating the documented historic appearance of the building’s Altering the documented appearance of the building’s interior 

interior features and finishes (including columns, cornices, base- features and finishes so that, as a result, an inaccurate depiction of 

boards, fireplaces and mantels, paneling, light fixtures, hardware, the historic building is created. For example, moving a feature from 

and flooring); plaster, paint, and finishes (such as stenciling or one area of a room to another, or changing the type or color of the 

marbleizing); and other decorative or utilitarian materials and finish. 

features. 

Installing mechanical systems and their components in the least 

obtrusive way possible so as not to impact the recreated interior 

spaces, features, or finishes while meeting user needs. 

Altering the historic plan or the recreated appearance unnecessarily 

when installing mechanical systems. 

Installing ducts, pipes, and cables in closets, service areas, and 

wall cavities. 

Installing ducts, pipes, and cables where they will intrude upon the 

historic appearance of the building. 

234 BUILDING INTERIOR 
[5] The parlor of the McLean House was 

reconstructed to its appearance on the occasion of 

Robert E. Lee’s surrender to Ulysses S. Grant in this 

room on April 9, 1865. 

BUILDING INTERIOR 235
RECONSTRUCTION

BUILDING SITE 

RECOMMENDED NOT RECOMMENDED 

Reconstructing building site features based on documentary and 

physical evidence. 

Reconstructing building site features without documentary and 

physical evidence. 

Inventorying the building site to determine the existence of Giving the building’s site an inaccurate appearance by basing the 

aboveground remains and subsurface archeological resources, reconstruction on conjectural designs or on features from other 

other cultural or religious features, or burial grounds, and using sites. 

this evidence as corroborating documentation for the reconstruction of related site features. These may include walls, fences, 

or steps; circulation systems, such as walks, paths, or roads; 

vegetation, such as trees, shrubs, grass, orchards, hedges, windbreaks, or gardens; landforms, such as hills, terracing, or berms; 

furnishings and fixtures, such as light posts or benches; decorative elements, such as sculpture, statuary, or monuments; water 

features, including fountains, streams, pools, lakes, or irrigation 

ditches. 

Recreating the historic spatial relationship between buildings and 

related site features. 

Changing the historic spatial relationship between buildings and 

related site features, or reconstructing some site features but not 

others, thereby confusing the depiction of the reconstructed site. 

236 BUILDING SITE 
[6] This lighthouse 

on Lake Ponchartrain 

in New Orleans was 

reconstructed after the 

historic 1890 lighthouse 

was destroyed by 

Hurricane Katrina. 

BUILDING SITE 237
 
RECONSTRUCTION

SETTING (DISTRICT / NEIGHBORHOOD) 

RECOMMENDED NOT RECOMMENDED 

Reconstructing features in the building’s historic setting based on 

documentary and physical evidence. 

Reconstructing features in the setting without documentary and 

physical evidence. 

Inventorying the setting to determine the existence of above- Giving the building’s setting an inaccurate appearance by basing 

ground remains and subsurface archeological resources, other the reconstruction on conjectural designs or on features from other 

cultural or religious features, or burial grounds, and using this locations. 

evidence as corroborating documentation for the reconstruction 

of missing features of the historic setting. These may include 

circulation systems, such as roads and streets; furnishings and 

fixtures, such as light posts or benches; vegetation, gardens, and 

yards; adjacent open space, such as fields, parks, commons, or 

woodlands; and important views or visual relationships. 

Recreating the historic spatial relationship between buildings and Changing the historic spatial relationship between buildings and 

landscape features in the setting. landscape features in the setting by reconstructing some features 

but not others, thereby confusing the depiction of the reconstructed 

setting. 

[7] The Muhlenberg Brigade Huts 

are reconstructions of nine log huts 

erected in 1777 at Valley Forge during 

the Revolutionary War. They have 

been reconstructed on the historic 

road with logs cut with modern power 

tools and finished with cement, unlike 

the original logs which were hand 

hewn and finished with traditional 

chinking. Photo: Rdsmith4 at Wikimedia 

Commons. 

238 SETTING (DISTRICT/ NEIGHBORHOOD) 
[8] The Palace of Fine Arts was designed by Bernard Maybeck and built for the 

1915 Panama-Pacific Exposition in San Francisco. The pavilion was intended to be 

temporary and, although it had a steel structure, the exterior was finished only 

with staff, an impermanent material composed of plaster and fiber. The building 

was not torn down after the exposition, and it eventually fell into ruin. In 1964, all 

but the steel structure was demolished, and the building was reconstructed with 

lightweight poured-in-place concrete. Photo: Kevinlcole at Wikimedia Commons. 

SETTING (DISTRICT/ NEIGHBORHOOD) 239
RECONSTRUCTION

240 Design: Lloyd Greenberg Design, LLC 
241
U.S. Department of the Interior 

National Park Service 

Technical Preservation Services