PRESERVATION 

BRIEFS 

Rehabilitating Interiors 

in Historic Buildings 

Identifying and Preserving Character-defining 

Elements 

H. Ward Jandl 

U.S. Department of the Interior 

National Park Service 

Cultural Resources 

Heritage Preservation Services 

A floor plan, the arrangement of spaces, and features and applied finishes may be individually or collectively important in 

defining the historic character of the building and the purpose for which it was constructed. Thus, their identification, retention, protection, and repair should be given prime consideration in every preservation project. Caution should be exercised in 

developing plans that would radically change character-defining spaces or that would obscure, damage or destroy interior 

features or finishes. 

While the exterior of a building may be its most 

prominent visible aspect, or its " public face," its interior can be even more important in conveying the 

building's history and development over time. 

Rehabilitation within the context of the Secretary of 

the Interior's Standards for Rehabilitation calls for the 

preservation of exterior and interior portions or 

features of the building that are significant to its 

historic, architectural and cultural values. 

Interior components worthy of preservation may include the building'S plan (sequence of spaces and circulation patterns), the building'S spaces (rooms and 

volumes), individual architectural features, and the 

various finishes and materials that make up the 

walls, floors, and ceilings. A theater auditorium or 

sequences of rooms such as double parlors or a lobby 

leading to a stairway that ascends to a mezzanine 

may comprise a building'S most important spaces. Individual rooms may contain notable features such as 

plaster cornices, millwork, parquet wood floors, and 

hardware . Paints, wall coverings, and finishing 

techniques such as graining, may provide color, texture, and patterns which add to abuilding's unique 

character. 

Virtually all rehabilitations of historic buildings involve some degree of interior alteration, even if the 

buildings are to be used for their original purpose. 

Interior rehabilitation proposals may range from 

preservation of existing features and spaces to total 

reconfigurations. In some cases, depending on the 

building, restoration may be warranted to preserve 

historic character adequately; in other cases, extensive 

alterations may be perfectly acceptable . 

This Preservation Brief has been developed to assist 

building owners and architects in identifying and 

evaluating those elements of a building'S interior that 

contribute to its historic character and in planning for 

the preservation of those elements in the process of 

rehabilitation . The guidance applies to all building 

types and styles, from 18th century churches to 20th 

century office buildings. The Brief does not attempt 

to provide specific advice on preservation techniques 

and treatments, given the vast range of buildings, but 

rather suggests general preservation approaches to 

guide construction work. 

Identifying and Evaluating the Importance 

of Interior Elements Prior to Rehabilitation 

Before determining what uses might be appropriate 

and before drawing up plans, a thorough professional 

assessment should be undertaken to identify those 

tangible architectural components that, prior to 

rehabilitation, convey the building's sense of time 

and place-that is , its "historic character." Such an 

assessment, accomplished by walking through and 

taking account of each element that makes up the interior, can help ensure that a truly compatible use for 

the building, one that requires minimal alteration to 

the building, is selected. 

Researching The Building's History 

A review of the building'S history will reveal why 

and when the building achieved significance or how 

it contributes to the significance of the district. This 

information helps to evaluate whether a particular 

rehabilitation treatment will be appropriate .to the 

building and whether it will preserve those tangible 

components of the building that convey its 

significance for association with specific events or 

persons along with its architectural importance. In 

this regard, National Register files may prove useful 

in explaining why and for what period of time the 
building is significant. In some cases research may 

show that later alterations are significant to the 

building; in other cases, the alterations may be 

without historical or architectural merit, and may be 

removed in the rehabilitation. 

Identifying Interior Elements 

Interiors of buildings can be seen as a series of 

primary and secondary spaces. The goal of the 

assessment is to identify which elements contribute to 

the building's character and which do not. 

Sometimes it will be the sequence and flow of spaces, 

and not just the individual rooms themselves, that 

contribute to the building's character. This is particularly evident in buildings that have strong central 

axes or those that are consciously asymmetrical in 

design. In other cases, it may be the size or shape of 

the space that is distinctive. The importance of some 

interiors may not be readily apparent based on a 

visual inspection; sometimes rooms that do not appear to be architecturally distinguished are associated 

with important persons and events that occurred 

within the building. 

Primary spaces, are found in all buildings, both 

monumental and modest. Examples may include 

foyers, corridors, elevator lobbies, assembly rooms, 

stairhalls, and parlors. Often they are the places in 

the building that the public uses and sees; sometimes 

they are the most architecturally detailed spaces in 

the building, earefully proportioned and finished with 

costly materials. They may be functionally and architecturally related to the building's external appearance. In a simpler building, a primary space may 

be distinguishable only by its location, size, proportions, or use. Primary spaces are always important to 

the character of the building and should be 

preserved. 

Secondary spaces are generally more utilitarian in 

appearance and size than primary spaces. They may 

include areas and rooms that service the building, 

such as bathrooms, and kitchens. Examples of 

secondary spaces in a commercial or office structure 

may include storerooms, service corridors, and in 

some cases, the offices themselves. Secondary spaces 

tend to be of less importance to the building and may 

accept greater change in the course of work without 

compromising the building's historic character. 

Spaces are often designed to interrelate both visually and functionally. The sequence of spaces, such 

as vestibule-haIl-parlor or foyer-Iobby-stair-auditorium 

or stairhall-corridor-classroom, can define and express 

the building's historic function and unique character. 

Important sequences of spaces should be identified 

and retained in the rehabilitation project. 

Floor plans may also be distinctive and 

characteristic of a style of architecture or a region. Examples include Greek Revival and shotgun houses. 

Floor plans may also reflect social, educational, and 

medical theories of the period. Many 19th century 

psychiatric institutions, for example, had plans based 

on the ideas of Thomas Kirkbride, a Philadelphia doctor who authored a book on asylum design. 

In addition to evaluating the relative importance of 

the various spaces, the assessment should identify architectural features and finishes that are part of the 

2 

Figure 1. This architect-designed interior reflects early 20th' century American taste: the checkerboard tile floor, wood wainscot, 

coffered ceiling, and open staircase are richly detailed and crafted 

by hand. Not only are the individual architectural features worthy 

of preservation, but the planned sequence of spaces-entry hall, stairs, stair landings, and loggia-imparts a grandeur that is 

characteristic of high style residences of this period. This interior 

is of Greystone, Los Angeles, California. Photography for HABS 

by Jack E. Boucher 

Figure 2. The interiors of mills and industrial buildings frequently 

are open, unadorned spaces with exposed structural elements. 

While the new uses to which this space could be put are manyretail, residential, or office-the generous floor-to-ceiling height 

and exposed truss system are important character-defining features 

and should be retained in the process of rehabilitation. 
DINING 

ROOM 

PARLOR 

KITCHEN 

SITTING 

ROOM 

APT. 2 

APT. ~ 

Figure 3. The floor plan at left is characteristic of many 19th century Greek Revival houses, with large rooms flanking a central hall. 

In the process of rehabilitation, the plan (at right) was drastically altered to accommodate two duplex apartments. The open stair was 

replaced with one that is enclosed, two fireplaces were eliminated, and Greek Revival trim around windows and doors was removed. 

The symmetry of the rooms themselves was destroyed with the insertion of bathrooms and kitchens. Few vestiges of the 19th century 

interior survived the rehabilitation. Drawing by Neal A. Vogel 

Figure 4. Many institutional buildings possess distinctive spaces or floor plans that are important in conveying the significance of 

the property. Finding new compatible uses for these buildings and 

preserving the buildings' historic character can be a difficult, if 

not impossible, task. One such case is Mechanics Hall in 

Worcester, Massachusetts, constructed between 1855 and 1857. 

This grand hall, which occupies the entire third floor of the 

building, could not be subdivided without destroying the integrity 

of the space. 

interior's history and character. Marble or wood 

wainscoting in corridors, elevator cabs, crown 

molding, baseboards, mantels, ceiling medallions, 

window and door trim, tile and parquet floors, and 

staircases are among those features that can be found 

in historic buildings. Architectural finishes of note 

may include grained woodwork, marbleized columns, 

and plastered walls. Those features that are 

characteristic of the building's style and period of 

construction should, again, be retained in the 

rehabilitation. 

Figure 5. The interior of a simply detailed worker's house of the 

19th century may be as important historically as the richly ornamented interior seen in figure 1. Although the interior of this 

house has not been properly maintained, the wide baseboards, flat 

window trim, and four-panel door are characteristic of workers' 

housing during this period and deserve retention during 

rehabilitation. 

Features and finishes, even if machine-made and 

not exhibiting particularly fine craftsmanship, may be 

character-defining; these would include pressed metal 

ceilings and millwork around windows and doors. 

The interior of a plain, simple detailed worker's 

house of the 19th century may be as important 

historically as a richly ornamented, high-style 

townhouse of the same period. Both resources, if 

equally intact, convey important information about 

the early inhabitants and deserve the same careful attention to detail in the preservation process. 

3 
The location and condition of the building's existing 

heating, plumbing, and electrical systems also need 

to be noted in the assessment. The visible features of 

historic systems-radiators, grilles, light fixtures, 

switchplates, bathtubs, etc.-can contribute to the 

overall character of the building, even if the systems 

themselves need upgrading. 

Assessing Alterations and Deterioration 

In assesessing a building's interior, it is important 

to ascertain the extent of alteration and deterioration 

that may have taken place over the years; these factors help determine what degree of change is appropriate in the project. Close examination of existing 

fabric and original floorplans, where available, can 

reveal which alterations have been additive, such as 

new partitions inserted for functional or structural 

reasons and historic features covered up rather than 

destroyed. It can also reveal which have been subtractive, such as key walls removed and architectural 

features destroyed. If an interior has been modified 

by additive changes and if these changes have not acquired significance, it may be relatively easy to 

remove the alterations and return the interior to its 

historic appearance. If an interior has been greatly 

altered through subtractive changes, there may be 

more latitude in making further alterations in the 

process of rehabilitation because the integrity of the 

interior has been compromised. At the same time, if 

the interior had been exceptionally significant, and 

solid documentation on its historic condition is 

available, reconstruction of the missing features may 

be the preferred option. 

It is always a recommended practice to photograph 

interior spaces and features thoroughly prior to 

rehabilitation. Measured floor plans showing the existing conditions are extremely useful. This documentation is invaluable in drawing up rehabilitation plans 

and specifications and in assessing the impact of 

changes to the property for historic preservation certification purposes. 

Drawing Up Plans and Executing Work 

If the historic building is to be rehabilitated, it is 

critical that the new use not require substantial alteration of distinctive spaces or removal of characterdefining architectural features or finishes. If an interior loses the physical vestiges of its past as well as 

its historic function, the sense of time and place 

associated both with the building and the district in 

which it is located is lost. 

The recommended approaches that follow address 

common problems associated with the rehabilitation 

of historic interiors and have been adapted from the 

Secretary of the Interior's Standards for Rehabilitation 

and Guidelines for Rehabilitating Historic Buildings. 

Adherence to these suggestions can help ensure that 

character-defining interior elements are preserved in 

the process of rehabilitation. The checklist covers a 

range of situations and is not intended to be allinclusive. Readers are strongly encouraged to review 

the full set of guidelines before undertaking any 

rehabilitation project. 

4 

Figure 6. This corridor, located in the historic Monadnock 

Building in Chicago, has glazed walls, oak trim, and marble 

wainscotting, and is typical of those found in late 19th and early 

20th century office buildings. Despite the simplicity of the 

features, a careful attention to detail can be noted in the patterned 

tile floor, bronze mail chute, and door hardware. The retention of 

corridors like this one should be a priority in rehabilitation projects involving commercial buildings. 

Figure 7. When the Monadnock Building was rehabilitated, architects retained the basic floor plan on the upper floors consisting 

of a double-loaded corridor with offices opelling onto it. The 

original floor-to-ceiling height in the corridors and outside 

offices-the most important spaces-was maintained by installing 

needed air conditioning ductwork in the less important anterooms. 

In this way, the most significant interior spaces were preserved 

intact. Drawing by Neal A. Vogel 
Recommended Approaches for Rehabilitating Historic Interiors 

1. Retain and preserve floor plans and interior 

spaces that are important in defining the overall 

historic character of the building. This includes the 

size, configuration, proportion, and relationship of 

rooms and corridors; the relationship of features to 

spaces; and the spaces themselves such as lobbies, 

reception halls, entrance halls, double parlors, 

theaters, auditoriums, and important industrial or 

commercial use spaces. Put service functions 

required by the building's new use, such as 

bathrooms, mechanical equipment, and office 

machines, in secondary spaces. 

2. Avoid subdividing spaces that are characteristic 

of a building type or style or that are directly 

associated with specific persons or patterns of 

events. Space may be subdivided both vertically 

through the insertion of new partitions or horizontally through insertion of new floors or mezzanines. The insertion of new additional floors 

should be considered only when they will not 

damage or destroy the structural system or 

obscure, damage, or destroy character-defining 

spaces, features, or finishes. If rooms have already 

been subdivided through an earlier insensitive 

renovation, consider removing the partitions and 

restoring the room to its original proportions and 

size. 

3. Avoid making new cuts in floors and ceilings 

where such cuts would change character-defining 

spaces and the historic configuration of such 

spaces. Inserting of a new atrium or a lightwell is 

appropriate only in very limited situations where 

the existing interiors are not historically or architecturally distinguished. 

4. A void installing dropped ceilings below ornamental ceilings or in rooms where high ceilings 

are part of the building's character. In addition to 

obscuring or destroying significant details, such 

treatments will also change the space's proportions. If dropped ceilings are installed in buildings 

that lack character-defining spaces, such as mills 

and factories, they should be well set back from 

the windows so they are not visible from the 

exterior. 

5. Retain and preserve interior features and 

finishes that are important in defining the overall 

historic character of the building. This might include columns, doors, cornices, baseboards, 

fireplaces and mantels, paneling, light fixtures, 

elevator cabs, hardware, and flooring; and 

wallpaper, plaster, paint, and finishes such as stenciling, marbleizing, and graining; and other 

decorative materials that accent interior features 

and provide color, texture, and patterning to walls, 

floors, and ceilings. 

6. Retain stairs in their historic configuration and 

location. If a second means of egress is required, 

consider constructing new stairs in secondary 

spaces. (For guidance on designing compatible new 

additions, see Preservation Brief 14, "New Exterior 

Additions to Historic Buildings.") The application 

of fire-retardant coatings, such as intumescent 

paints; the installation of fire suppression systems, 

such as sprinklers; and the construction of glass 

enclosures can in many cases permit retention of 

stairs and other character-defining features. 

7. Retain and preserve visible features of early 

mechanical systems that are important in defining 

the overall historic character of the building, such 

as radiators, vents, fans, grilles, plumbing fixtures, 

switchplates, and lights. If new heating, air conditioning, lighting and plumbing systems are installed, they should be done in a way that does 

not destroy character-defining spaces, features and 

finishes. Ducts, pipes, and wiring should be installed as inconspicuously as possible: in secondary 

spaces, in the attic or basement if possible, or in 

closets. 

8. Avoid "furring out" perimeter walls for insulation purposes. This requires unnecessary removal 

of window trim and can change a room's proportions. Consider alternative means of improving 

thermal performance, such as installing insulation 

in attics and basements and adding storm 

windows. 

9. Avoid removing paint and plaster from traditionally finished surfaces, to expose masonry and 

wood. Conversely, avoid painting previously unpainted millwork. Repairing deteriorated plasterwork is encouraged. If the plaster is too 

deteriorated to save, and the walls and ceilings are 

not highly ornamented, gypsum board may be an 

acceptable replacement material. The use of paint 

colors appropriate to the period of the building's 

construction is encouraged. 

10. Avoid using destructive methods-propane and 

butane torches or sandblasting-to remove paint or 

other coatings from historic features . Avoid harsh 

cleaning agents that can change the appearance of 

wood. (For more information regarding appropriate 

cleaning methods, consult Preservation Brief 6, 

" Dangers of Abrasive Cleaning to Historic 

Buildings.' ') 

5 
Figure 8. Furring out exterior walls to add insulation and suspending new ceilings to hide ductwork and wiring can change a room 's 

proportions and can cause interior features to appear fragmented. In this case, a school was converted into apartments, and individual 

classrooms became living rooms, bedrooms, and kitchens. On the left is an illustration of a classroom prior to rehabilitation; note the 

generous floor-to-ceiling height, wood wainscotting, molded baseboard, picture molding, and Eastlake Style door and window trim. After 

rehabilitation, on the right, only fragments of the historic detailing survive: the ceiling has been dropped be/ow the picture molding, the 

remaining wainscotting appears to be randomly placed, and some of the window trim has been obscured. Together with the subdivision 

of the classrooms, these rehabilitation treatments prevent a clear understanding of the original classroom 's design and space. If thermal 

performance must be improved, alternatives to furring out walls and suspending new ceilings, such as installing insulation in attics and 

basements, should be considered. Drawings by Neal A. Vogel 

Figure 9. The tangible reminders of early mechanical systems can 

be worth saving. In this example, in the Old Post Office in 

Washington, D. c., radiators encircle Corinthian columns in a 

decorative manner. Note, too, the period light fixtures. These 

features were retained when the building was rehabilitated as 

retail and office space. Photo: Historic American Buildings Survey 

6 

Figure 10. In this case plaster has been removed from perimeter 

walls, leaving brick exposed. In removing finishes from historic 

masonry walls, not only is there a loss of historic finish, but raw, 

unfinished walls are exposed, giving the interior an appearance it 

never had. Here, the exposed brick is of poor quality and the 

mortar joints are wide and badly struck. Plaster should have been 

retained and repaired, as necessary. 
Figure 11. These dramatic "before" and "after" photographs show a severely deteriorated space restored to its original elegance: plaster 

has been repaired and painted, the scagliola columns have been restored to match marble using traditional craft techniques, and missing 

decorative metalwork has been re-installed in front of the windows. Although some reorganization of the space took place, notably the 

relocation of the front desk, the overall historic character of the space has been preserved. These views are of the lobby in the Willard 

Hatel, Washington, D.C. Credit: Commercial Photographers (left); Carol M. Highsmith (right) 

Meeting Building, Life Safety and Fire 

Codes 

Buildings undergoing rehabilitation must comply 

with existing building, life safety and fire codes. The 

application of codes to specific projects varies from 

building to building, and town to town. Code requirements may make some reuse proposals impractical; in other cases, only minor changes may be 

needed to bring the project into compliance. In some 

situations, it may be possible to obtain a code 

variance to preserve distinctive interior features. (It 

should be noted that the Secretary's Standards for 

Rehabilitation take precedence over other regulations 

and codes in determining whether a rehabilitation 

project qualifies for Federal tax benefits.) A thorough 

understanding of the applicable regulations and close 

coordination with code officials, building inspectors, 

and fire marshals can prevent the alteration of significant historic interiors. 

Sources of Assistance 

Rehabilitation and restoration work should be 

undertaken by professionals who have an established 

reputation in the field. 

Given the wide range of interior work items, from 

ornamental plaster repair to marble cleaning and the 

application of graining, it is possible that a number of 

specialists and subcontractors will need to be brought 

in to bring the project to completion. State Historic 

Preservation Officers and local preservation organizations may be a useful source of information in this 

regard. Good sources of information on appropriate 

preservation techniques for specific interior features 

and finishes include the Bulletin of the Association for 

Preservation Technology and The Old-House Journal; 

other useful publications are listed in the 

bibliography. 

Protecting Interior Elements During 

Rehabilitation 

Architectural features and finishes to be preserved 

in the process of rehabilitation should be clearly 

marked on plans and at the site. This step, along with 

careful supervision of the interior demolition work 

and protection against arson and vandalism, can prevent the unintended destruction of architectural 

elements that contribute to the building's historic 

character. 

Protective coverings should be installed around 

architectural features and finishes to avoid damage in 

the course of construction work and to protect 

workers. Staircases and floors, in particular, are subjected to dirt and heavy wear, and the risk exists of 

incurring costly or irreparable damage. In most cases, 

the best, and least costly, preservation approach is to 

design and construct a protective system that enables 

stairs and floors to be used yet protects them from 

damage. Other architectural features such as mantels, 

doors, wainscotting, and decorative finishes may be 

protected by using heavy canvas or plastic sheets. 

Summary 

In many cases, the interior of a historic building is 

as important as its exterior. The careful identification 

and evaluation of interior architectural elements, after 

undertaking research on the building's history and 

use, is critically important before changes to the 

building are contemplated. Only after this evaluation 

should new uses be decided and plans be drawn up. 

The best rehabilitation is one that preserves and protects those rooms, sequences of spaces, features and 

finishes that define and shape the overall historic 

character of the building. 
This Preservation Brief is based on a discussion paper 

prepared by the author for a National Park Service 

regional workshop held in March, 1987, and on a 

paper written by Gary Hume, "Interior Spaces in 

Historic Buildings," October, 1987. Appreciation is 

extended to the staff of Technical Preservation Services Branch and to the staff of NPS regional offices 

who reviewed the manuscript and provided many 

useful suggestions. Special thanks are given to Neal 

A. Vogel, a summer intern with the NPS, for many 

of the illustrations in this Brief. 

This publication has been prepared pursuant to the 

National Historic Preservation Act of 1966, as 

amended. Preservation Briefs 18 was developed 

under the editorship of Lee H. Nelson, FAIA, Chief, 

Preservation Assistance Division, National Park Service, U.S. Department of the Interior, P.O. Box 37127, 

Washington, D.C. 20013-7127. Comments on the 

usefulness of this information are welcomed and may 

be sent to Mr. Nelson at the above address. This 

publication is not copyrighted and can be reproduced 

without penalty. Normal procedures for credit to the 

author and the National Park Service are appreciated. 

Selected Reading List 

There are few books written exclusively on preserving historic interiors, and most of these tend to focus 

on residential interiors. Articles on the subject appear 

regularly in The Old-House Journal, the Bulletin of the 

Association for Preservation Technology, and Historic 

Preservation Magazine. 

Ferro, Maximilian 1., and Melissa 1. Cook. Electric 

Wiring and Lighting in Historic American Buildings. 

New Bedford, Massachusetts: AFC/A Nortek 

Company, 1984. 

Fisher, Charles E. Temporary Protection of Historic Stairways During Rehabilitation Work. Preservation Tech 

Note. Washington, D. c.: Preservation Assistance 

Division, National Park Service, U.S. Department 

of the Interior, 1985. 

Jennings, Jan, and Herbert Gottfried. American Vernacular Interior Architecture 1870-1940. New York: 

Van Nostrand Reinhold Company, 1988. 

Johnson, Ed. Old House Woodwork Restoration: How to 

Restore Doors, Windows, Walls, Stairs and Decorative 

Trim to Their Original Beauty. Englewood Cliffs, 

New Jersey: Prentice-Hall, Inc., 1983. 

Labine, Clem, and Carolyn Flaherty (editors). The 

Old-House Journal Compendium. Woodstock, New 

York: The Overlook Press, 1980. 

The Secretary of the Interior's Standards for Rehabilitation 

and Guidelines for Rehabilitating Historic Buildings. 

Washington, D. c.: Preservation Assistance Division, National Park Service, U.s. Department of 

the Interior, rev. 1983. 

U.S. Department of Housing and Urban Development. Rehabilitation Guidelines, volumes 1-11. 

Washington, D.C.: U.S. Department of Housing 

and Urban Development, 1980-84. 

Winkler, Gail Caskey, and Roger W. Moss. Victorian 

Interior Decoration: American Interiors 1830-1900. 

New York: Henry Holt and Company, 1986. 

October 1988 

Cover: Detail of carving on interior shutter. Hammond-Harwood 

House, Annapolis, Maryland. 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402