Mid-Century Modern Preservation: A Conservator’s Dilemma

Stephen HartleyDepartment Head of Historic Preservation

Savannah Technical Collegeshartley@savannahtech.edu

After the Second World War the United States experienced a tremendous boom in housing, causing a dramatic shift in the way Americans live. These new suburbs, based on the model first practiced by William Levitt on Long, Island, New York in the 1950’s were constructed on a principle of quick, inexpensive housing using standardized construction techniques. Material suppliers responded to this mechanizedway of building, creating materials such as framing lumber and gypsum products in standardized sizes, further restructuring building techniques and creating the model for new construction that we still use today. Indeed, it has been stated that these new construction standards put an end to such trades as plastering and lathing, and specialized others, such a framing and finish carpenters.

In the last twenty years many of these early suburban subdivisions and buildingshave, under the Secretary of Interior Standards, progressed into the classification of historic, thus eligible for all the programs and protections granted to structures of the pre World War Two era. While it is important to acknowledge the historic importance ofthese cultural landscapes, this classification also raises important questions in regards to the physical preservation of such sites. How do conservators effectively maintain materials designed to have limited life spans? Since these buildings were constructed using semi-skilled labor and a production line mentality, what is the role of the preservation artisan in these structures? This session, will explore the physical and ethical dilemmas encountered in the conservation of post-World War Two structures and sites from the evolving perspective of the conservators and building artisans.

Introduction: Mid-Century Modern and Preservation’s Future?

History is a continuum that flows without interruption into the present instant and the future1

1 Kelli Shapiro “From Modernism to McDonald’s: Ideology, Controversy, and the Movement to Preserve the Recent Past”. Journal of Architectural Education. Vol. 60 no.2(2007): 7.

Since its inception, the historic preservation movement has

been rife with controversy. From the beginnings of the movement’s

fight to save historic sites associated with the founding of

America, to its modern conception the preservation movement has

faced questions of what is to be saved as well as what is

authentic and compatible conservation solutions. Today the

largest controversy facing this movement is the preservation of

Mid Century Modern sites, structures and neighborhoods, the vast

numbers of sites eligible for listing on the National Register of

Historic Places associated with Mid Century Modern structures, as

well as long held prejudice and disdain for those sites from many

corners of the preservation realm. Regardless of individual

preservationists’ notions of these structures, it is clear that

the preservation of these sites will play a major role in the

future of the historic preservation movement throughout the

world.

Mid-Century Modern structures are typically identified as

those built between 1930 and 1975. These structures were built

with new technologies and construction methods and represent a

large proportion of America’s built heritage. These buildings

have recently approached or surpassed the fifty year mark, thus

making them eligible for listing on the National Register. Their

experimental technologies and production line construction made

them innovative, drastically and permanently changing the

construction field in the United States and beyond. It is that

same innovation however, which threaten the long term

preservation of these sites as the materials used have proven to

have shorter lives than their traditional counterparts as well as

potentially hazardous conditions for both residents and workers.

There has been a significant amount of research performed

pertaining to the historical value of post World War II

structures, the procedures for documentation, and conservation of

these sites. Most research however has been performed on high

style examples of Mid Century Modern architecture, such as

glazing issues at the Guggenheim Museum and the repair of thin

shelled concrete structures throughout the country. Little

research has been performed however on the responsible

preservation of vernacular structures in post World War II

suburbs, although these buildings represent not only a large

portion of Mid-Century Modern buildings, but a large percentage

of America’s built environment as a whole. While most of these

buildings will not be listed on the National Register

individually, many are contributing structures in historic

district applications focusing on Post World War II development.

This paper will focus on the role of the craftsman and

conservator on these structures, and the future of the heritage

craft in this growing subsection of the preservation field.

Housing the Nation: History of Post WWII Structures

Modernism is both the genesis and the bête noir of historic preservation.2

The history of design and construction of post World War II

structures begins with the United States entrance into the Second

World War at the end of 1941. The Federal Government encouraged

the research and development of new construction techniques and

materials. The demand for mass produced war materials and housing

drove the economy, as private production all but ceased. Large

companies switched all production to the wartime effort, refining

methods for mass production for all aspects of American life.

Builders constructed large housing estates to accommodate

2 Thomas C. Jester and David Fixler. “Modern Heritage: Progress, Priorities and Prognosis” Association for Preservation Technology Bulletin Vol. 27 No. 2-3 (2011): 3.

thousands of workers at factories, shipyards, and military

installations. It was this practice which became perfected after

the war.

By the end of 1945, an estimated 3,600,000 families were in

need of homes3. Returning veterans, eager to start families and

supported by the GI Bill, were in a desperate search for housing.

Builders responded by constructing 1,023,000 in 1946 alone.

Between 1946 and 1975, manufacturers constructed more than 40

million new homes4.

The Federal Government supported this new construction boom

in both direct and indirect manners. The Federal-Aid Highway Act

of 1956 authorized $25 billion dollars to construct a “National

System of Interstate and Defense Highways”5, opening millions of

acres of previously distant land for development of new suburbs.

The National Housing Act of 1936, meant to spur home ownership

and decrease the stock of substandard housing during the Great

Depression, established the Federal Housing Authority (FHA). The

3 Joseph B. Mason, History of Housing in the U.S. 1930-1980. Houston: Gulf Publishing Company. (1982): 45-47. 4 Ibid., 45-47.5 Federal Highway Administration, “The Dwight D. Eisenhower National System ofInterstate and Defense Highways”, Federal Highway Administration, http://www.fhwa.dot.gov/reports/routefinder (accessed 17 November 2012).

FHA established minimum guidelines for new construction,

including house and room size, lot minimums and access to public

amenities. It also insured mortgages, allowing smaller required

down payments as well as eventually extending payment schedules

to thirty years.

The construction of this number of properties could not have

been possible without a drastic shift in the method that

structures were completed. According to the U.S. Bureau of

Statistics, in 1938 the typical building constructed four or less

single family homes per year, and even fewer had the capacity for

constructing ten a year6. Builders changed their tactics in

regards of how they build. Following the methods used during the

war years, builders subdivided labor into individual jobs, much

like a production line, where crews would move from building to

building performing the same repetitive task. William Levitt, the

most famous of all post World War II builders determined that

there were twenty-six individual building components which

required specific crews. These crews could move faster than their

6 National Cooperative Highway Research Program, “A Model for Identifying and Evaluating the Historic Significance of Post-World War II Housing.” Transportation Research Board. (2012): p.66.

pre war counterparts, and by 1950 his company was producing one

four bedroom house every 16 minutes7. Increasing productivity and

standardizing production would be easier and more profitable for

the builder, but would change the construction industry forever,

drastically reducing the need for master craftsman and artisans,

and increasing the need for semi-skilled labor which only needed

to perform the same process repeatedly.

Traditional methods of supply and delivery could not

accommodate this new method of construction, and suppliers

responded to the changes. Many builders developed their own

methods of pre-fabrication, building components of the structures

off-site and delivering them to the building location. Still

others prepackaged materials needed to construct the individual

homes, delivering the materials within feet of the structure.

Pre fabrication of components and entire buildings was not a

new idea. During the war, companies quickly built entire

neighborhoods to respond to wartime demand, including the

prefabricated construction of 977 homes in 73 days in Vallejo,

California8, but the construction of millions of structures would

7 Ibid. 68. 8 Ibid., 85.

require an expansion of production as well as the experimentation

with new products.

The mass production of materials meant the standardization

of house styles and layout throughout the country. Plywood, first

patented in 1865, was originally intended for furniture, but

found a role in the building industry. Made in standard 4 foot by

8 foot panels it eliminated the high ceilings and unique room

configuration found before the war. Indeed the plywood industry

experienced a 380 percent increase in production from 1939 to

1947, and the number of plywood manufactures rose from 50 to

1509. Plastics, whose production increased significantly during

the war, found its way into the construction industry by means of

products such as Formica and Bakelite. Vinyl windows, first

produced by the Anderson Window Company, became industry standard

by 1960. These new products would make production easier, but

would be issues for both homeowners and conservators in the

future.

Respecting the Recent: Mid Century Modern as Historic

9 Thomas C. Jester. Twentieth Century Building Materials. (New York: McGraw Hill, 1995). 132-134.

Many, Many people became historic preservationists out of their hatred of modern design10

The historical implications of this post war expansion

cannot be denied. Nor can the changes it spurred within the

construction industry be ignored. Buildings designed by prominent

architects such as Eerro Sarrien and I.M. Pei have been

designated as historic sites based in their innovative design and

their representation of post war design. As increased number of

post World War II structures reach the 50 year mark required for

designation, early suburban developments are now being classified

as historic districts. But how can these developments, repeated

thousands of times throughout the country, be listed as historic,

and what does this mean for the future of the preservation

artisan role within the preservation field?

Many of the high style post World War II buildings have been

listed either before or immediately after they meet the 50 year

mark required by the Secretary of Interior Standards. Those who

were listed before the requirement were done under Consideration

G within the standards which allows for structures to be listed

10 Shapiro. P.8.

if they are of “exceptional importance”11. Some structures which

have been listed under this criterion have included architect

designed buildings, military installations, and sites associated

with the beginnings of the atomic age. The number of structures

listed under this criteria has remained relativity small however.

Since the 1970’s sites listed with association within the last

twenty years have statistically represented less than three

percent of the listings on the National Register12.

As the years march on and more structures are eligible under

the fifty year rule, structures and district applications have

increased dramatically. While individual buildings within early

suburban developments will most likely not be listed individually

as historic structures, given the abundance of examples as well

as prejudice against these structures, they will be listed as

contributing structures within National Register Districts.

National Register District nominations for post war

developments can be justified under several factors. The older

style of nomination, which may have included an argument 11 Jeanne Lambin. Preserving Resources form the Recent Past. (Washington D.C.: Preservation Press, 2003), 5. 12 John Spinkle “Of Exceptional Importance”: The Origins of the “Fifty-Year rule” in Historic Preservation” The Public Historian Vol. 29 No. 2 (spring 2007): 102.

pertaining to a large collection of structures from one time

period are not enough to justify inclusion as a district under

the statement of significance portion of the application process.

Nor is the argument pertaining to individual craftsmanship or

ethnic building groups, as the structures represent a production

process rather than bespoke building techniques or designs.

Indeed most post war districts have been established on the

argument of innovative planning schemes, connection with local

industry, or a connection with an individual builder or company

plan.

This method of nomination, while not new, has rapidly

increased within the last twenty years. In Savannah Georgia, a

city know for a high percentage of Victorian era architecture,

the Fairway Oaks-Greenview Historic District has been established

under the argument it was “the first mid 20th century suburban

residential development intended for middle to upper class white

homeowners outside the Savannah city limits featuring new-to-

Savannah curvilinear street layout with cul-de-sacs and

irregularly shaped wooded lots”13. Several other districts

13 National Cooperative Highway Research Program pp. 30-31.

surveys, including Kensington Park subdivision and Habersham

Woods have been performed, with varying levels of success.

All these districts represent a social change for the City

of Savannah, as well as a technological change for the building

traditions for the region. But the buildings represented therein

have been replicated repeatedly throughout the region, and in

many respects are still be constructed toady. The buildings

within the Fairway Oak-GreenView District, if listed as

contributing structures are now eligible for tax credits for the

rehabilitation of historic properties. How will these buildings

be preserved, and will preservation artisans be needed for their

rehabilitation? This question is a looming issue for the

preservation field.

Repairing the Disposable: Conservation Issues For Production LineProducts

In this case the material itself was of less importance than the values it represented as a product of industry.14

No discussion on the role of craftsman and conservators in

mid century modern preservation can exist without first

14 David N. Fixler. “Appropriate Means to an Appropriate End: Industry, Modernism, and Preservation” Association for Preservation Technology Bulletin. Vol. 39. No. 4. (2008): 32.

discussing some of the material introduced during its

construction. While the list of new products is seemly endless,

most, such as Zenitherm and Cuschocel had very short application

time frames. Some found use in high design buildings, such a thin

clad stone and glass curtain walls. Still others found roles in

remolding of older structures, such as asphalt siding which

mimicked brick veneers, and permastone, which provided the same

application for those which desired stone cladding. Three of the

major products which were found extensively on vernacular

structures built during this time frame which are in need of

further study in terms of conservation techniques are aluminum

siding and cladding, asphalt shingles and asbestos siding.

Aluminum was first patented by the Aluminum Company of

America (Alcoa) in 1889. Its use however was limited to

industrial purposes for the initial years of its life. During the

war, Aluminum production soared because of its extensive use in

the aircraft industry. After the war the aluminum producers

turned their attention to the building industry as a way to

market their products. Aluminum found its way into window frames,

siding and entire structures. The Reynolds Metals Company, a

subsidiary of Reynolds Tobacco, premiered an all aluminum

building in 1949, announcing that within a few months it would be

available in "unlimited quantities within a few months.15” The

product never made it to market.

While aluminum found its way into the building trades in

many aspects, from kitchen appliances to full polished panels for

architect designed buildings, perhaps that its greatest

contribution to the mid century modern building is in the realm

of siding. Sheet metal siding had been patented as early as 1903,

but it wasn’t until Frank Hoess patented the locking panel joint

in the 1930’s did the use of aluminum siding take off. The

locking joint was a simple way to overlap panels to avoid water

infiltration. This simple design caught the attention of major

aluminum producers, and by 1946 aluminum siding was being

installed on new housing developments throughout the Northeast.

After 18 months of production, the Reynolds Company estimated

that it had already sold enough metal products to side and roof

141,113 five-room homes.16

15 John Lauber “And it Never Needs Painting: The Development of Residential Aluminum Siding” Association for Preservation Technology Bulletin Vol. 31 No.2/3. (2000):20. 16 Ibid., p.21.

Aluminum siding continued to evolve, producing flash coated

painted materials in a rainbow of colors, even embossing sheets

to give the appearance of brick and stone. Until it was

supplanted by less expensive vinyl siding in the mid 1960’s, it

was the dominate cladding material for new construction.

Aluminum has its drawbacks as a building material. It does

not weather well, particularly in environments with high salt

contents. The flash paint technique used to originally coat the

product, if adhered incorrectly, would trap moisture inside the

product, causing it to rust from the inside. Finally, the

material dents and damages easily, causing unsightly damage that

is typically repaired in the same method one would repair an

automobile after an accident. Aluminum siding has long been the

bane of preservationist, as it was used to cover older wood

siding due to its guarantee of low maintenance and a promise that

it “never needs painting”. Now we have reached a point in history

where one of the preservationists most hated materials warrants

preservation.

Asphalt roofing materials have existed since the beginning

of the twentieth century. Asphalt shingles were originally

produced by impregnating an organic mat, as known as rag with

asphalt. While the asphalt was still hot, the producer added

granules to produce a coating on the outer surface of the

material. Asphalt shingles are sold in “squares”, with each

square covering a 10 foot by 10 foot section of roof, or roughly

100 square feet of roofing materials. Various producers created a

variety of styles for shingles, including what is commonly

referred to as two and three tab styles in which the shingles

were produced in consecutive two or three shingle styles, which

when installed on a roof will create a repetitive pattern.

Asphalt shingles were relatively inexpensive, readily

available, and easily installed. While other roofing materials

such a standing seam metal and clay tile required specialized

work crews, asphalt shingle were designed to be installed using

semi-skilled labor, often time the homeowner themselves.

Unlike other roofing materials, asphalt shingles have a very

short life span. In the best conditions, asphalt shingles will

last 30 years before needing replacement. In areas with high

temperatures, that number can be reduced by half, given the

thermal degradation experienced by the product. The longevity of

this material poses a major problem for preservationists.

While removing damaged or failed material and replacing it with

in-kind alternatives is common practice within the preservation

field, the shear variety of shingles produced since the 1930’s

poses a serious authenticity issue for preservationists. During

the restoration of Harry and Bess Truman’s home in Independence,

Missouri the National Park Service faced such a dilemma. The

home, built in 1867 with additions made in 1885, had a two tab

shingle system, installed a few years prior to Harry Truman’s

death. Since the building was considered historic due to its

association with Truman, the Park Service decided to replace the

failing shingle with in kind replacements. The issue that arose

was the original producer of the shingles had closed and larger

companies would not produce replacements unless the Park Service

ordered a minimum of 700 squares (70,000 square feet). The

project required only 35 squares17.

Attempting to find overstock supplies would be difficult,

due to the fact that it would be virtually impossible to locate

17 Alan W. O’Bright Replacing Historic Asphalt Shingles (Chicago: Preserving the Recent Past Proceedings, 1995) P. IV-115.

all 35 squares in one location and the possibility in variances

due to batch differences of the granules. After five years of

attempting to locate replacement shingles and trying to convince

manufacturers to reproduce a small batch, a method was found. A

company was willing to supply 40 squares of single tab shingles,

which would then be manually slotted to produce the two tab

appearance. The manual slotting technique was developed by the

Williamsport Preservation Training Center, who also performed the

install. After five years of planning, the project was completed.

The installation was proclaimed “anti-climactic; the job was like

any other asphalt roofing job”18

This project is an example of an emerging issue when dealing

with modern material restorations. It is not the installation of

the materials which causes the greatest issue, but rather it is

acquiring a mass produced material with a short life span.

Salvaging stone, brick, or even wood, while costly and

troublesome, can be done, there is currently no way to salvage a

material such as asphalt shingles once installed on a structure.

18 Ibid p. IV-119.

While aluminum and asphalt preservation represents important

issues in the craft of preservation and procurement of materials,

asbestos products represent another issue; safety.

Asbestos was typically mixed with other materials to produce a

product. Asbestos was inexpensive to process, was resistant to

fire, and had almost miracle levels of flexibility and wear

resistance as well as an ability to bond to almost any other

material. Asbestos was used as a product in insulation, flooring,

roofing and siding applications. Its use was continued until

1973, when the Environmental Protection Agency banned the use and

production of asbestos19. Today, it is illegal to manufacture or

sell asbestos in the United States.

Asbestos based materials are now considered historic, and

therefore eligible for preservation. Indeed there has been some

research done on the correct methods of preserving asbestos

siding using Portland cement patches. The preservation of these

materials raise is not only ethical but legal questions. Legally,

asbestos products may only be handled by certified asbestos

abatement companies, who are charged with safe removal and

19 Amy Lamb Woods. Keeping a Lid on it: Asbestos-Cement Building Materials (Chicago: Preserving the Recent Past Proceedings, 1995) 3-82.

disposal of the materials. Insurance companies, once asbestos has

been identified on site, will often not insure a building until

the material has been removed, regardless of the condition of the

asbestos.

The health issues surrounding asbestos are well documented.

Asbestos is hazardous when it is in its friable state, which is

identified as the exposure of asbestos fibers to the air.

Asbestos which is not in friable condition is not consider

hazardous, nor is products containing small amounts of asbestos

as an additive. Even in a non-friable state, dust control and

proper Personal Protective Equipment (PPE) is required to clean

or repair the material.

While asbestos is certainly not the only hazardous material

potentially found on preservation sites, its potential for

serious illness raises safety concerns for preservation artisans.

Many companies refuse to work on sites continuing asbestos,

including many of the large trade unions operating in the

Northeast. Asbestos also raises concerns for property owners,

particularly those with children. The removal of asbestos will

certainly affect the historic integrity of a structure, but the

retention of such materials may cause long term health issues.

These issues have not been addressed in detail by preservation

artisans, abatement and insurance companies dealing with historic

structures. Further research need to be performed on the future

of historic asbestos materials, which will become a prominent

issue in the near future.

How do we fix it?: The Role of the Conservator and Craftsman in

Mid-Century Modern

Lack of experience and underdeveloped repair technology are the main causes of the current predicament20

As shown, the changes in construction processes after the

Second World War have drastically altered the American landscape

and therefore the historic preservation field. Many of the

procedures and techniques for preserving these structures have

been put in place in terms of advocacy and documentation, but the

role of the conservator and preservation artisan in the

preservation of these sites has not fully developed.

Conservators study the physical and chemical composition of

structures and materials, and perform best practices in the

20 Susan MacDonald. “Authenticity is More than Skin Deep: Conserving Britain’sPostwar Concrete Architecture” Association for Preservation Technology Bulletin Vol. 28 No. 4. (1997): 43.

conservation of sites. Typically, conservators perform work on

architect design buildings and monuments. Their specialized

training and complicated equipment are out of the reach for the

owners of most vernacular structures. Conservators have already

begun researching the failure modules and correct procedures in

two specific areas of mid century modern structures; curtain

walls and concrete. Research has also been conducted on thin

masonry veneers such as granite and marble. These materials are

typically not applied structures found in post war housing

developments.

The conservators’ biggest obstacle to working on mid-century

modern buildings may be the buildings themselves. The

experimental manner in which they were built have proven to have

its faults, and many structures from this era are already showing

signs of extreme fatigue, and the sheer amount of work that needs

to be performed may encourage owners to demolish the structure.

Built in a time of cheap energy, mid century modern structures

are not withstanding the test of time on energy efficiency,

further encouraging demolition. As Susan Bronson and Thomas

Jester state:

“Another drawback is that many buildings of the recent past are currently in a state of technical obsolesce-

theirexposed concrete is decaying or their curtain wall

requiresrepair or replacement-and appropriate, economical

conservationsolutions are not as obvious as for early heritage.”

Craftsmen face two issues when working on post war sites.

The first issue again comes from the buildings themselves. The

mass production methods of original construction are designed to

be assembled with unskilled or semi-skilled labor. Given the

skills required to originally construct them, the repair

techniques are similarly semi-skilled. Big box “do it yourself”

stores encourage homeowners to complete the work themselves.

Contractors who typically build new structures, which use the

same techniques perfected in the 1950’s can use the same

techniques to repair almost any vernacular post war structure.

The preservation artisan must be willing to adapt their

techniques and approaches when working on these buildings.

The second issue arises when examining the materials used to

construct these buildings. Some have been found to be hazardous

to work with. Some were never designed to last. Asphalt shingles,

gypsum wallboard, linoleum flooring and other products were not

designed for a long life span. Preservation of these components

will be difficult, and often times impossible, requiring

replacement. Other materials were mass produced using industrial

processes, and cannot be replicated on site. As Michael Lynch

notes: “You cannot make twenty feet of aluminum extrusion in your

backyard shop the way you can run off a wood molding”21. As shown

by the National Park Service’s work of Truman’s home, the

acquiring the material which needs to be replaced is much more

challenging than the application of those materials. Much like

the specialized companies which replicate products for pre-war

structures, the field of those creating products for post war

structures is expanding. A company having the capacity to extrude

large quantities of aluminum siding or creating small productions

of shingles will require a significant investment of capital in

order to produce. Until the demand increases, production will

not. Until this occurs, craftsmen will be forced to make

decisions about in-kind materials which may be disavowed as the

field progresses.

21 Michael Lynch “What Are We Going to Do with the Recent Past in the Not Too Distant Future” Association for Preservation Technology Bulletin. Vol. 23. No.2 (1991) 6.

The decisions made by both conservators and craftsman in

regards to best practices in midcentury modern buildings are

certainly likely to stir controversy. The concept of authenticity

in historic sites is always in debate, and Mid Century Modern

structures are certain to contribute to these conversations. The

innovative methods of construction, production techniques of

materials, and hazardous nature of sites will contribute to the

argument which is central to the role of the conservator and

craftsman in regards to Mid Century Modern buildings: What is

authentic in a disposable site.

Conclusion: What is the Future of the Recent Past?

Creativity is important in determining approaches to apparently insurmountable problems22

While the number of National Register listed buildings from

the post war period is small, that number will continue to grow

as years progress and attitudes evolve pertaining to these

structures adapt. This will lead to a change in the role of both

the craftsman and the conservator in the preservation field.

Conservators must learn to adapt their best practices techniques

22 MacDonald. P.43.

to becoming economically viable, as more of the buildings they

are employed to save requires repair. Preservation artisans, who

have spent years studying the traditional techniques practiced in

this country, must expand their knowledge to include construction

techniques of the post war era. They must also adapt to the fact

that they will be facing a greater base of competition from new

build contractors and homeowners themselves. Traditional

craftsmanship is a specialized field, and that field must expand

their specialization in order to remain viable.

In an academic sense, Mid Century Modern structures provide

an exciting field of study. For those working in the field

however, it entails challenges and dangers not fully explored.

Further research must be performed on the best ways to deal with

structures built with impermanent and sometimes hazardous

materials. Questions of authenticity, value and practice must all

be addressed to ensure that this historic cultural change in our

built landscape is preserved for the future.

Bibliography

Federal Highway Administration, “The Dwight D. Eisenhower National System of Interstate and Defense Highways”, Federal Highway Administration, http://www.fhwa.dot.gov/reports/routefinder (accessed 17 November2012).

Fixler, David N. “Appropriate Means to an Appropriate End: Industry, Modernism, and Preservation” Association for Preservation Technology Bulletin Vol. 39 No. 4. (2008): 31-36.

Jester, Thomas C. 20th Century Building Materials. New York: McGraw Hill, 1995.

Jester, Thomas C. and David Fixler. “Modern Heritage: Progress, Priorities and Prognosis” Association for Preservation Technology Bulletin Vol. 27 No. 2-3 (2011). p.3.

Lambin, Jeanne. Preserving Resources From the Recent Past. Washington D.C.: Preservation Press, 2003.

Lauber, John. “And it Never Needs Painting: The Development of Residential Aluminum Siding” Association for Preservation Technology BulletinVol. 31 No.2/3 (2000): 17-24.

Lynch, Michael. “What Are We Going to Do with the Recent Past in the Not Too Distant Future” Association for Preservation Technology Bulletin.Vol. 23. No.2 (1991): 6.

MacDonald, Susan. “Authenticity is More than Skin Deep: Conserving Britain’s Postwar Concrete Architecture” Association for Preservation Technology Bulletin Vol. 28 No. 4. (1997): 37-44.

Mason, Joseph B. History of Housing in the U.S. 1930-1980. Houston: Gulf Publishing Company, 1982.

National Cooperative Highway Research Program. A Model for Identifying and Evaluating the Historic Significance of Post-World War II Housing. Washington D.C.: Transportation Research Board. 2012.

O’Bright, Alan W. “Replacing Historic Asphalt Shingles” in Preserving the Recent Past Proceedings. Chicago, Ill. 1995. P. IV-115.

Shapiro, Kelli. “From Modernism to McDonald’s: Ideology, Controversy, and the Movement to Preserve the Recent Past” Journal of Architectural Education. Vol. 60 No.2 (2007): 6-14.

Spinkle, John. “Of Exceptional Importance”: The Origins of the “Fifty-Year rule” in Historic Preservation” The Public Historian Vol. 29 No. 2 (spring 2007): 81-103.

Woods, Amy Lamb. “Keeping a Lid on it: Asbestos-Cement Building Materials” in Preserving the Recent Past Proceedings. Chicago Ill. 199: 3-82.