12 PRESERVATION 

BRIEFS 

The Preservation of 

Historic Pigmented 

Structural Glass 

(Vitrolite and Carrara Glass) 

u.s. Department of the Interior, National Park Service 

Rocky Mountain Regional Office, Cultural Resources Division 

The dramatic growth and popularization of the early 20th 

century Art Deco, Streamline, and Moderne architectural 

styles were fueled, in part, by technological advances in the 

building materials industry. New products, such as 

stainless steel and plastics, enlarged the realm of 

architectural design. The more traditional materials, on the 

other hand, quickly developed fresh, innovative forms and 

uses. For example, the architectural glass industry became 

especially creative, introducing a series of new glass 

products known as structural glass. Used predominately 

for wall surfacing, these now familiar products included 

glass building blocks, reinforced plate glass, and pigmented 

structural glass. Pigmented structural glass, popularly 

known under such trade names as Carrara Glass, Sani 

Onyx (or Rox), and Vitrolite, revolutionized the business 

and rapidly became a favorite building material of the 

period's architects and designers. 

The versatility of pigmented structural glass contributed 

to its popularity. Not only could the material be applied to 

both the exterior and interior, the glass could be 

sculptured, cut, laminated, curved, colored, textured, and 

illuminated. Often applied directly over existing 

architecture to remodel older buildings- as well as in new 

construction-a veneer of pigmented structural glass had 

the ability to define a building'S architectural character as 

new and up-to-date. Pigmented structural glass also 

complemented the period's silvery metal accents and 

affinity for slick, shiny surfaces. A successful application of 

a structural glass veneer often resulted in a streamlined 

look characteristic of the Art Moderne architectural style. 

As tastes changed and production costs rose, however, 

pigmented structural glass fell into disfavor and disuse by 

mid-20th century. With today's rekindled interest in the 

Art Deco, Art Moderne, and Streamline styles the 

preservation and replacement of pigmented structural glass 

have now become an integral part of many rehabilitation 

projects, particularly in relation to commercial storefronts. 

This brief, then, was developed in order to address some of 

the major deterioration problems associated with 

pigmented structural glass and to recommend methods for 

maintaining, repairing, and-if necessary-replacing 

damaged or missing pieces of pigmented structural glass. 

--ooa 

Early Manufacture and Use of Pigmented 

Structural Glass 

Although pigmented structural glass enjoyed widespread 

popularity from the beginning of the Great Depression to 

the outbreak of World War II, its origins can be traced to 

the turn of the century. In 1900, the Marietta 

Manufacturing Company claimed to be the first producer 

of pigmented structural glass, rolling the first sheet of a 

"substitute for marble," Sani Onyx. Penn-American Plate 

Glass Company quickly joined its ranks, manufacturing 

white and black Carrara Glass around 1906. PennAmerican Plate Glass no doubt selected the name 

"Carrara" for the white glass's close resemblance to the 

white marble of the Carrara quarries of Italy. Shortly 

thereafter, Libby-Owens-Ford Glass began production of 

their own version called Vitrolite. 

Initially, Sani Onyx was produced for such utilitarian 

purposes as refrigerator linings. Manufacturers perceived 

the glass as a practical, easily cleaned, and sanitary 

product. Its uses, however, expanded rapidly. By the 

second decade of the 20th century, consumers viewed 

pigmented structural glass as an inexpensive substitute for 

marble counter tops, table tops, wainscoting, and restroom 

partitions. The first large-scale interior architectural 

application of pigmented structural glass was in the 

Woolworth Building (1912-1913) when Architect Cass 

Gilbert sheathed the restrooms with Carrara Glass. Later 

in the decade, the decorative possibilities of the glass 

received even more attention. 

As the century progressed, architects began to substitute 

pigmented structural glass for traditional building 

materials in new construction. Large expanses of 

architectural detailing such as sleek door surrounds, 

polished interior lobbies, and striking commercial 

storefronts became expected and familiar features within 

new, expanding downtown business districts in the 1920s 

and 1930s (see fig. 1). 

In addition, designers quickly found pigmented 

structural glass to be an increasingly popular modernizing 

material for older and out-of-date buildings. As a result. 

storefronts became a favorite subject for "modernization." 

New Deal programs, including low-rate insured Federal 
Fig. I. The Club Moderne. Anaconda. Montana. reflects the exceptional 

historic detailing associated with pigmented structural glass- polishedmirror finish. rounded corners. and horizontal polychrome bands. Photo: 

Jet Lowe. Historic American Engineering Record. 

Housing Administration loans in combination with a 

"Modernize Main Street" competition sponsored by the 

Architectural Record and Libby-Owens-Ford Glass, 

stimulated the remodeling fervor. By 1940, pigmented 

structural glass veneers had become synonymous with the 

"modern look." The numerous pigmented structural glass 

storefronts surviving today are testimony to the popularity 

of these remodelings. 

The winners of the 1935 "Modernize Main Street" 

competition illustrated what many considered good 

contemporary design. The judges of the competition, 

including Albert Kahn, William Lescaze, and John Root, 

awarded architects who incorporated "simplicity," 

"economy," "unbroken horizontal lines," "expressed 

function," and "pure colors contrasting light and shadow" 

in their designs. Simplicity of design often translated into 

curvilinear recessed entries which protected consumers 

from inclement weather-eliminating cumbersome canvas 

or metal awnings-and providing additional display 

window space (see fig. 2). The first and second stories of 

many 19th century storefronts had disappeared by 1940, 

hidden behind simple, yet striking, modern pigmented 

structural glass veneers. 

Although the glass was originally produced only in 

white, the range of colors from which architects could 

choose soon included black, beige, and ivory. By the 

1930s, more exotic colors such as tropic green, forest 

green, robin blue, suntan, and jade were offered by the 

principal manufacturers in addition to the stock colors of 

gray, yellow, and tan. Agate or marbleized treatments in 

fanciful imitation of the "real" materials were also 

available. The back surface was occasionally silvered to 

give a rich mirror finish (see fig. 3). Most of these colors 

and finishes were available in standard thicknesses from 

11/32 inch to 1-1/4 inches. The glass's smooth exterior 

was obtained either by fire polishing during the normal 

glass fabrication process or by mechanical polishing when 

a high mirror finish was desired. In both cases, the 

smooth, slick, reflective surface made the material intensely 

2 

Fig. 2. The extensive use of rich. black Vitrolite in this design impressed 

the judges of the 1935 "Modernize Main Street" competition. and the 

architects were awarded first prize. Courtesy. The Architectural Record. 

popular with architects or designers who sought the 

"modern look." 

Although focusing on exterior applications, architects 

also utilized pigmented structural glass for interior spaces 

(see fig. 4), replacing the porous and more expensive 

marble and offering a highly polished, uniform visual 

appearance in keeping with design trends of the 1920s and 

1930s. Other uses of the material included small, high-style 

installations in hotels, office lobbies, bars, and lounges (see 

figs. 5 and 6). 

Fig. 3. The Russell Stover Candies. Nashville. Tennessee. shows the 

company's historic use of deep. mirrored violet pigmented structural glass 

storefronts. Photo: Douglas A. Yorke. Jr .• AlA. 
Fig. 4. White pigmented structural glass was used in this remodeling of the 

U.S. Custom House. Denver. Colorado. Photo: Gregory D. Kendrick . 

Historic Material and Installation Specifications 

Early 20th century advertisers often promoted pigmented 

structural glass as a new panacea of the building materials 

industry. Their claims were not without substance. Unlike 

masonry units such as terra cotta, pigmented structural 

glass would not warp, swell, or craze. Nor was the glass 

highly susceptible to staining, fading, or burning. Like 

most glass products, it was impervious to moisture and 

could be easily maintained and usually cleaned with a 

damp cloth. Adaptable to a wide range of uses, the glass 

could be colored and textured to attain brilliant visual 

qualities. Perhaps most important, when compared to 

marble, the glass was easier to handle, less expensive to 

use, and simpler to install. 

The key to proper preservation and repair of both 

interior and exterior pigmented structural glass is a 

thorough understanding of the original material 

specifications and detailed installation techniques. 

Fortunately, these specifications and techniques remain 

virtually unchanged from their first early 20th century 

application (see fig. 7). 

Exterior Installation 

Essentially, the glass veneer was applied to a dry, smooth, 

and solid masonry or plaster-on-masonry substrate using 

an asphaltic masonry adhesive. Manufacturers 

recommended against affixing the glass directly to wood, 

either lath or paneling. Glass thicknesses of 11 / 32 inch or 

7/ 16 inch were most common for commercial storefronts. 

Shelf angles-18-gauge brass or stainless steel, 3 inch 

square with a 1/ 2 inch leg fastened directly to the masonry 

substrate- were used to provide additional support. 

Inserted along the bottom edge of the panels, they 

supported every second course of glass and were thus 

spaced not more than 3 feet apart. Horizontally, the angles 

were spaced approximately one every 18 inches with at 

least two used for any piece. 

Actual installation involved applying daubs (2 inches to 3 

inches in diameter) of hot asphalt-based mastic adhesive to 

the glass and then attaching the glass directly to the 

substrate. Manufacturers of the mastic recommended 

coverage of about 50 percent of the glass panels. A full 3 

inch width of mastic coverage was recommended around 

detail edges or any holes in the panels. The mastic was 

applied in a molten state after being melted in an electric 

"hot cup." (Hot cups are still manufactured for this 

specific purpose and are made to hold enough mastic for a 

single daub.) 

The next step in the installation procedure was to push 

the glass panel onto the masonry substrate. Every 

horizontal seam and abutment was separated by a 1/ 16 

inch thick adhesive cork tape recessed from the front 

surface by 1/ 8 inch. Vertical edges were kept apart at a 

uniform 1/ 32 inch. In either case, the joint opening was 

then buttered with a joint cement which was colored to 

match the surrounding glass. 

Proper detailing at the edges of the veneer could prolong 

the life of the pigmented structural glass. For example, to 

prevent possible chipping and cracking of the glass where 

it met the sidewalk, a cushion of neoprene or leather was 

provided and the exposed surface then caulked (see fig. 8). 

The side edges of the glass were detailed in a variety of 

methods or the glass simply terminated at the desired 

location with the ends ground smooth (see fig. 9). In either 

case, the edge was secured to the substrate with a mastic 

and the joints or void filled with joint cement or caulking 

compound. Where the edge of the glass abutted another 

material, such as the brickwork of a neighboring 

storefront, the glass was held back 1/ 8 inch to 1/ 4 inch 

from the adjacent material. The gap was usually filled with 

pliable caulk to permit expansion and to prevent moisture 

migration (see figs. 10 and II). 

Interior Installation 

Construction methods and materials were quite similar 

for interior and exterior uses of pigmented structural glass. 

Most interior veneers were the same thickness and 

approximate dimension of those used for exteriors. Minor 

differences did, however, exist. For example, joints 

between the pieces of glass could be reduced to little more 

Fig. 5. Gentlemen's Lounge. Hermitage Hotel. Nashville. Tennessee. 

presents a dynamic visual arrangement of horizontal black and green 

pigmented structural glass panels. Photo: Douglas A . Yorke. Jr., A I A . 

3 
Fig. 6. Owners of the Hadley Dean Glass Company Warehouse. SI. Louis. Missouri. preserved the unusual polychrome pigmented structural glass 

interior lobby . Photo: Paul Marshall. 

than hairline cracks for interior applications due to the 

limited thermal expansion of the substrate. On the other 

hand, the use of glass as an indoor ceiling material created 

unusual installation requirements. 

Ceiling slabs 11 / 32 inch in thickness were attached to 

I inch x 4 inch wood furring strips with mastic (a full 4 

inch width coverage was recommended around the edge of 

the panels). Brass wood screws and small rosettes, 

protected with felt exterior covers, provided additional 

support (see fig. 12). 

As a nonveneer material, pigmented structural glass was 

generally used for counter and table tops and restroom 

partitions. Counter tops presented little or no unusual 

installation problems. Partitions, however, often involved 

formidable installation challenges; for example, enormous 

glass panels, weighing up to 16.25 pounds per square foot 

and measuring I inch to 1-1 / 4 inches in thickness were 

used. The desired thickness was obtained by cementing two 

7/ 16 inch slabs together with mastic. To accommodate this 

heavy yet fragile load, a reinforced support and connection 

system was developed which utilized metal sleeves, iron 

anchors, and steel straps bolted directly into the glass 

panels. 

Reasons for Damage 

Although deterioration of pigmented structural glass itself 

is rare or unheard of, failure of the mechanical support 

system which bonds the glass modules to the wall is almost 

always the cause of failure, cracking, slipping, or loss. 

Therefore, damage is usually attributable to one or a 

4 

combination of the following: 

• Deterioration of the Joint Cement 

• Hardening and Failure of the Mastic Adhesive 

• Impact Due to Accident/ Vandalism 

Deterioration of the Joint Cement 

Historically, the cement joint between glass panels was 

intended to provide an integrated, watertight surface. 

Unfortunately, the traditional joint cement did not possess 

a long lifespan. Cracked or open joints have been the 

consequence, usually resulting from improper original 

application of the cement or from the normal thermal 

expansion and contraction cycle associated with 

substrate -~k:llUm glass 

joint 

cement 

cork 

tape 

mastic 

11:0111111-- glass 

shelf angle 

. 1J1IIII-- joint cement 

Basic exterior construction details (Owgs: D. Beals for BUIlding ConservaCion TKhnologyl 

Fig. 7. In the installation process. hot asphaltic mastic was applied to 

the ribbed or textured back of each glass panel. The panel was then 

pressed against a masonry wall and supported by metal shelf angles which 

were usually bolted to the masonry substrate on 3-foot centers. The joints 

between the panels were filled with cork tape or joint cement. The end 

result was a modular veneer of clean. uniform glass panels. Courtesy. 

Bulletin for the Association for Preservation Technology. 13 (/981). 
mastic 

Sections at sidewalk level. 

Fig. 8. Courtesy, Bulletin for the Association for Preservation 

Technology, 13 (1981). 

weathering. Cracked or open cement JOlnts then 

accelerated deterioration of the masonry substrate and/ or 

the mastic adhesive bond by allowing water to penetrate 

the internal system. Water entering the system weakened 

the bond between the mastic and the masonry substrate or 

rusted the anchoring shelves. This caused the individual 

glass panels to gradually slip away from their original 

positions and fall. 

Hardening and Failure of Mastic Adhesive 

Failure due to long-term hardening of the original mastic 

adhesive has accounted for a substantial loss of pigmented 

structural glass panels. The petroleum-based mastics 

normally possessed a 30 to 40 year lifespan. Once 

flexibility of the adhesive is lost, the glass panels become 

vulnerable to slippage and eventual destruction (see 

fig. 13). 

Impact Due to Accident/ Vandalism 

Glass breakage through impact is virtually impossible to 

prevent. The material is, by its nature, vulnerable to loss 

through vandalism or accident (see fig. 14). 

Maintenance and Repair of Pigmented 

Structural Glass 

The maintenance of a dry masonry substrate, mastic, and 

metal anchors is essential to the longevity of a pigmented 

structural glass veneer. Thus, repointing cracked or open 

joints- particularly at ground level where glass abuts 

concrete-and caulking of slightly cracked glass panels is 

an ongoing concern. Where drainage to conduct water 

away from the wall is faulty or insufficient, the problem 

should be immediately corrected. For example, roof 

flashing, downspouts, and gutters should be repaired or 

new systems installed. 

Mitered Bullnose Square 

('(tenor corners. 

Fig. 9. Courtesy, Bulletin for the Association for Preservation 

Technology, 13 (1981). 

adjoining building pointing 

('1 .. ' minimum) 

Termination details. 

Fig. 10. Courtesy, Bulletin for the Association for Preservation 

Technology, 13 (1981). 

Repair of Cement Joints 

Cracked or open cement joints, particularly in exterior 

applications, can present a serious preservation problem 

because they permit water to penetrate the internal system 

of a pigmented structural glass veneer. Rusting metal 

anchors or deteriorating mastic adhesive may be the result. 

Although the traditional joint cements are easily colored 

and may be neatly applied, they are no longer 

recommended for the repair of pigmented structural glass 

because their longevity is limited. Present-day silicone 

compounds, on the other hand, offer flexibility, relative 

impermeability to moisture, ease of installation, and a long 

lifespan. The proper color match can be obtained by 

mixing the compound with tinted polyester resins. 

Patching Glass Cracks 

Any glass panel that can be repaired should not be 

replaced. Thus, the decision to repair or replace damaged 

historic pigmented structural glass panels always needs to 

be made on a case-by-case basis. In many instances, the 

damage may be so minor or the likelihood of finding 

suitable replacement glass panels so small that repairing, 

reanchoring, and/ or stabilizing the damaged glass is the 

only prudent choice. 

A slightly chipped or cracked pigmented structural glass 

panel left unrepaired will inevitably become a source of 

water infiltration. Careful patching of those cracks with an 

appropriately colored, flexible caulk will deter moisture 

penetration while still allowing expansion and contraction 

with temperature fluctuations. Although patching is by no 

5 
•

flaSh,ng 

.. extruded metal 

JOlnl 

,ement 

~ 

Fig. II . Courtesy, Bulletin for the Association for Preservation 

Technology, 13 (1981). 

means a permanent solution, it will help to protect the 

material from further damage due to the effects of weather 

(see fig. 15). 

Removal of Pigmented 

Structural Glass Panels 

Removal of existing glass panels from a wall in order to 

reapply mastic adhesive that is failing or to replace broken 

panels (see also paragraphs on "Replacement of . 

Damaged/ Missing Glass Panels") is an exacting operatIOn 

because the mastic used to attach the glass panels to the 

wall may have become hard and extremely difficult to 

separate from the ribbed backing of the glass. Fortunately, 

commercial solvents may be purchased which are capable 

of softening the hardened mastic, such as methyl ethyl 

ketone, methyl isobutyl ketone, and acetone. These 

solvents may be introduced into the cavity behind the glass 

with a crook-necked polyethylene laboratory squeeze bottle 

or a large syringe without a needle. (Solvents should be 

stored in fire-safe metal containers until used and should 

also be handled with extreme care so that they do not 

come into contact with the skin.) Such methods make it 

easy to direct the solvent into the narrow separation 

between the glass panel and the wall with a minimum of 

waste and effort. After the mastic has softened, two people 

using a taut piano wire sawing down from the top can 

safely and efficiently separate the glass from the wal~. 

If time is a concern, a fast, simple removal method 1S to 

carefully pry the panels off with a broad flat tool such as a 

nail puller. A small piece of wood placed between the flat 

tool and glass will minimize splintering of the edges. 

Stubborn pieces can be removed by squirting the mastic 

with a solvent (as described above), then letting it set 

6 

glass 

Ceiling constructIon. 

metal rosette 

wlwood screw 

JOint cement 

and cork; age 

mastic 

glass 

. . '., 

Fig. 12. Courtesy, Bulletin for the Association for Preservation 

Technology, 13 (1981). 

Fig. 13. The pigmented structural glass panel has separated and fallen, 

exposing the substrate and hardened, brittle daubs of mastic. Photo: 

Douglas A. Yorke, Jr., AlA. 

several minutes. This procedure softens the mastic, making 

it more pliable. The piano wire / sawing method may be 

useful in removing the topmost glass panels of a 

continuous face where no edges occur. The wire can be 

effectively worked into the joints and will cut through the 

mastic. With care, a high percentage of the glass panels 

can be salvaged using this method (see fig. 16). 

Another method of removing glass panels that has 

proven to be effective if the solvent-and-wire method 

cannot be used, involves directing steam at the face of the 

panel in order to soften the mastic. Although this method 

can be time-consuming, averaging up to lO minutes per 

panel, the glass can be successfully removed. Remaining 

" . "41 ':":':~':" Lf 'I 

Fig. 14. The vast majority of damaged pigmented structural glass panels 

are found at ground level, the result of vandalism or improper caulking 

between the glass panel and the concrete sidewalk . Photo: Thomas 

Keohan. 
Fig. 15. Owners of this small barber shop, Denver, Colorado. have 

successfully preserved the historic character of their pigmented structural 

glass storefront by patching the cracked panels with a dark caulking 

compound. Photo: Gregory D. Kendrick . 

mastic may then be removed by directing additional steam 

on the panel, soaking the panels in hot water to further 

soften the mastic-or applying appropriate chemical 

solvents- and scraping off the softened mastic. 

Reinstallation of Glass Panels 

Due to an accumulation of soot behind the glass, the 

surface of the masonry substrate usually needs to be 

cleaned before panels or a wall of pigmented structural 

glass are reinstalled. After removal of the glass panels has 

been completed, the substrate should be cleaned using a 

mild detergent and water, then allowing sufficient time for 

it to dry. The old glass must also be thoroughly cleaned of 

soot, grease, or old mastic that would impair bonding of 

the new adhesive. A mild solution of water and household 

ammonia will generally clean the surface adequately. The 

glass may then be reinstalled following a system 

established during removal. 

In reinstalling the glass panels (or new panels to replace 

any historic glass that has been broken), it is recommended 

that the mastic adhesive used throughout the 1930s and 

1940s be used, because it is still the best bonding material. 

Although modern silicone compounds offer workability, 

adhesion, and flexibility, they tend to be expensive when 

used in the necessary quantity. On the other hand, butyl 

adhesives do not provide sufficient adhesion on nonporous materials such as pigmented structural glass. 

Polysulfide-based, synthetic rubber sealants do not have 

the short set-up time of the traditional hot-melt asphalt 

mastic and thus present installation difficulties. Finally, 

epoxies do not appear to have the plasticity essential for 

longevity of a glass veneer. 

Replacement of Damaged/ Missing Glass Panels 

Production of pigmented structural glass in the United 

States ceased several years ago, and only in rare cases have 

inventories been discovered. Yet, checking all the obvious 

and not so obvious sources for replacement may prove to 

be rewarding. Occasionally, long established "jobbers" will 

have a limited supply of pigmented structural glass. It is 

not uncommon for glass contractors to buy entire stocks 

of glass when companies or supply houses go out of 

business and to use this original material to make repairs 

on historic buildings. 

Locating a source for new glass similar to the historic 

pigmented structural glass is as much of a problem as 

finding the original glass. Until about lO years ago, glass 

companies near Bavaria in Western Germany were 

producing a pigmented structural glass called "Detopak." 

At present, these factories appear to be the only suppliers 

in the world. The glass is made in small batches, and the 

color can vary due to the lack of modern mechanization in 

the pigmenting process. For this reason, American 

importers generally only deal in white and black glass. 

If a satisfactory replacement panel cannot be located, 

one alternative is to remove a piece of glass from an 

inconspicuous part of the building and position it on the 

more prominent facade. Modern spandrel glass, a new 

substitute material described below, may be considered as 

a replacement for the less visible area. 

Substitute Material for Damaged/ Missing Glass 

Panels 

If replacement glass cannot be found to replace broken or 

missing panels, a compatible substitute material may be 

considered if it conveys the same visual appearance as the 

historic material, i.e., color, size, and reflectivity. Two of 

the historic producers of pigmented structural glass now 

manufacture a similar product known generically as 

Fig. 16. A worker carefully removes a large glass panel by placing a 

small piece of wood between a flat prying bar and the glass. then exerting 

steady pressure. The majority of panels were removed without damage 

using this procedure. Photo: Thomas Keohan . 

7 
"spandrel glass" and marketed under the trade names of 

Spandrelite and Vitrolux. This heavy plate glass has a 

ceramic frit or colored ceramic surface fired to the back of 

the glass. Stock colors are available in a range of grays, 

browns, bronzes, and black. Custom colors are also 

available. 

A second option simulates the appearance of pigmented 

structural glass by spraying paint, carefully tinted to match 

the historic glass, onto the back of plate glass. However, 

the paint may fade over a long period of time and thus 

require periodic reapplication. 

Sheet plastics may also be used and are available in a 

range of colors, sizes, and thicknesses. These materials are 

more suitable for interior applications, however, where the 

negative effects of ultra-violet light are lessened. 

Conclusion 

The preservation of pigmented structural glass remains more 

a materials issue than a detailing pro blem. The glass panels 

were and are extremely susceptible to breakage due to 

accident or vandalism. In addition, many of the historic 

installation materials such as the mastic adhesive and joint 

cement did not possess a long lifespan. Periodic maintenance, 

inspection, careful repair, and selective replacement- in like 

kind- are essential for the longevity of any historic pigmented 

structural glass veneer. 

Even though the architectural glass industry has 

continued to expand its production of different types of 

glazing, the imaginative innovations of Carrara Glass, Sani 

Oxyx, and Vitrolite in the early part of this century have 

not been surpassed. New technology, combined with 

human artistry, produced exteriors and interiors alive with 

color and dimension. Glittering movie palaces, sparkling 

restaurants, and streamlined storefronts as well as the 

more mundane kitchens, restrooms, and laboratories 

exemplified the extensive variety and potential of 

pigmented structural glass. Carrara Glass, Sani Onyx, and 

Vitrolite were integrally linked to the architecture and 

interior design of the 1930s and 1940s and helped to define 

what was "modern." Thus, every effort should be made to 

preserve this significant historic material in both the 

innovative buildings of the Art Deco, Streamline, and 

Moderne styles as well as the "modernization" of earlier 

structures. 

This Preservation Brief is partially adapted from an article entitled 

"Material Conservation for the Twentieth Century: The Case for 

Structural Glass," written by Douglas A. Yorke, Jr., AlA, which 

appeared in the Bulletin for the Association for Preservation Technology. 

13 (1981), and from an unpublished- manuscript by Thomas L. Hensley of 

the National Park Service. Preservation Brief 12 was edited by Gregory 

D. Kendrick, Historian, under the technical editorship of de Teel 

8 

Patterson Tiller, both of the Rocky Mountain Regional Office, National 

Park Service. We wish to thank Mr. Yorke for permission to use his 

article and photographic material. Finally, we want to acknowledge 

Thomas G. Keohan, Field Representative, Mountains/ Plains Regional 

Office, National Trust for Historic Preservation for donating photographs 

and assistance to this project. 

Comments on the usefulness of this information are welcomed and 

should be sent to Lee H. Nelson, AlA, Chief, Preservation Assistance 

Division, National Park Service, Department of the Interior. This 

publication is not copyrighted and can be reproduced without penalty. 

Normal procedures for credit to the authors and the National Park 

Service are appreciated. 

Additional Reading 

Gay, Charles Merick and Parker, Harry. Materials and Methods of 

Architectural Construction. New York: John Wiley and Sons, 

Inc., 1931. 

Glass, Paints, Varnishes and Brushes: Their History, Manufacture and 

Use. New York: Pittsburgh Plate Glass Company, 1923. 

Hornbostel, Caleb. Construction Materials. New York: John Wiley and 

Sons, Inc., 1978. 

Kidder, Frank E. and Parker, Harry. The Architect's and Builder's 

Handb ook, 15th ed., New York: John Wiley and Sons Inc., 

1913. 

McGrath, Raymond and Frost, A.c. Glass in Architecture and 

Decoration. London: The Architectural Press, 1937. 

"Modernize Main Street." Architectural Record 78 (October 1935): 

209- 266. 

Ramsey, Charles George and Sleeper, Harold Reeves. Architectural 

Graphic Standards, 3rd ed., New York: John Wiley and Sons, 

Inc., 1941. 

Richey, H. G. Richey's Reference Handbook for Builders, Architects and 

Construction Engineers. New York: Simmons-Boardman 

Publishing Corporation, 1951. 

The Secretary of the Interior's Standards f or Rehabilitation and 

Guidelines f or Rehabilitating Historic Buildings (Revised 1983). 

Washington, D.C.: Technical Preservation Services Division, 

U.S. Department of the Interior. 

Standard Building Code. Birmingham, Alabama: Southern Building Code 

Congress International, Inc., 1979. 

Sweet's Architectural Catalogue, 22nd annual ed., New York: F.W. 

Dodge Corporation, Sweet's Catalogue Service, 1927-1928; 

Section B, pp. 1406- 1409, (Vitrolite product literature). 

Sweet's Indexed Catalogue of Building Construction. New York: 

Architectural Record Company, 1906. 

Time Saver Standards, 1st ed., New York: Architectural Record , 1946. 

Yorke, Douglas A. Jr. , AlA. "Materials Conservation for the Twentieth 

Century: The Case for Structural Glass." APT 13 (1981): 19-30. 

February 1984