SUSTAINABLE ARCHITECTURE AND ITS RELATIONSHIP TO INDUSTRIALIZED BUILDING
DANA SCOTT HAUKOOS
A THESIS PRESENTED TO THE GRADUATE SCHOOL THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN ARCHITECTURAL STUDIES
UNIVERSITY OF FLORIDA
TABLE OF CONTENTS
Industrialized Building and Sustainability ............. 1
What is Sustainability?................................1
Focus of This Study....................................8
2 REVIEW OF LITERATURE...................................9
Industrialized Housing Today..........................74
3 EMERGY ANALYSIS OF VARIOUS CONSTRUCTION MATERIALS.....83
Introduction .......................................... 83
Methods ............................................... 84
Flat Glass Products..................................101
Discussion of Results.................................101
4 COMPARISONS OF FIRST COSTS FOR CONSTRUCTION
ALTERNATIVES VIA EMERGY ANALYSIS...................107
Methods .............................................. 107
Discussion of Results................................122
5 INDUSTRIALIZED BUILDING AND SUSTAINABILITY:.........126
Indices for Sustainability...........................126
Summary and Conclusions .............................131
A EMERGY EVALUATION CALCULATIONS FOR BUILDING
MATERIALS IN CHAPTER 3............................13 5
B MASS PER GIVEN UNIT FOR VARIOUS BUILDING
C DETAIL MATERIAL AND COST ESTIMATES FOR DESIGN
D DETAIL MATERIAL AND COST ESTIMATES FOR DESIGN
E DETAIL MATERIAL AND COST ESTIMATES FOR DESIGN
Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science in Architectural Studies
SUSTAINABLE ARCHITECTURE AND ITS RELATIONSHIP TO INDUSTRIALIZED BUILDING
Dana Scott Haukoos August, 199 5
Chairman: Ira Winarsky
Major Department: Architecture
While the concept of sustainable architecture is broadly understood in general terms, a comprehensive quantitative measure is more difficult to define. This study proposes a basis for one such analytical methodology based on the theory of ecological energetics known as eMergy (spelled with an "M") analysis. The goal is to develop a method by which the sustainability of various approaches to architecture can be compared, and to look at industrialized building from this perspective.
EMergy analysis involves determining the total amount of energy of a single type that is required to produce a given amount of material. This result is called the eMergy per unit mass. EMergy evaluation of several commonly used building
materials are presented, including wood, steel, concrete, and glass products. This data, combined with conventional cost estimating techniques, is used to estimate first costs both in terms of monetary and eMergy units. A case study is presented which compares a residential design of three alternative construction materials and methods; two alternatives represent conventional construction approaches and the third represents an industrialized approach.
EMergy analysis is shown to provide a means of analytically comparing diverse inputs to the building process (materials, fuels, human services, etc.) based upon a common metric. It can fully accommodate the concept of life-cycle assessment, including issues of reuse, recycling, and renewable resources.
CHAPTER 1 INTRODUCTION
Industrialized Building and Sustainability
Industrialized building and its cousin modern architecture claim efficiency and economy among their founding principles. From an ecological perspective, however, much of their legacy is anything but efficient and economical. Some would go as far to say that the model of industrialized construction is the antithesis of sustainable architecture. This study asks the question "to what extent ^ are the methods, materials, philosophy, and aesthetics of industrialized building compatible with the growing contemporary concerns for restructuring society around the popular concept of sustainability?" To address this question, however, requires a working definition of what sustainability is and a method by which it might be measured. That is the second major issue this study will address.
What is Sustainability?
On one hand the general idea of what the concept is all about is simple--a process (of building, in this case) which can be sustained for an indefinite period. This "implies a limitation on the degree and rate of human impact such that
the natural carrying capacity of the earth's ecosystems can be perpetually maintained" (Thayer, 1972, p.99). The analysis of sustainability, however, is a much less clearly understood problem. This study applies the theory of ecological energetics known as "eMergy analysis" in the process of developing and advancing quantitative measures of sustainability as applied to the analysis of architecture and the built environment.
Different Perspectives Based on Scale of Consideration
Different perspectives on the efficiency and economy of a building's design are a result of which factors have been considered in the analysis. In general terms, this is referred to as where one places the boundaries of the system to be analyzed. Early proponents of industrialized building were focused primarily on the aspects of mass production and the efficiencies of human labor that could result. They were interested in the "first costs" of a building. Often the design of these structures took little consideration of the climate in which they were placed, relying heavily instead on fossil fuels to produce a comfortable human environment. This attitude was economically practical as long as fossil fuels remained inexpensive, but with the energy shortages of the 1970s, a broadening of perspective began to emerge. The monetary cost of fossil fuels increased, providing an incentive to take into consideration a building's operating costs during its design.
At the same time, others took an even broader look at the consumption of energy. The concept of the "embodied energy" of materials took into account the fact that fossil fuels were utilized in all processes of the conversion of raw materials into products. The accounting techniques devised to measure these costs are known as life-cycle assessment (LCA) or resource and environmental profile analysis (REPA). Figure 1-1 illustrates this concept.
Energy Energy Energy Energy Energy
Figure 1-1. A System Diagram for Life-Cycle Assessment (AIA, 1992, Intro.V 2)
Since the beginnings of the energy shortages of the 1970's until today, the scope of concerns facing architects and builders has expanded even further. Confronted with the need to reduce energy consumption in the design of their buildings, many designers of the past two decades responded by developing "super-tight" buildings which minimized the
loss of energy by more carefully sealing each of the paths of potential infiltration of outside air. While this did reduce a significant source of energy loss, it also frequently had the unanticipated effect of what is called "sick building syndrome". The infiltration air had been providing fresh-air ventilation, which when restricted led to the build up of toxic gases due to off-gassing of many contemporary construction materials. Thus, designers have been forced to deal with new human health concerns in conjunction with their pursuit of energy efficiency.
Other concerns, arising out of a growing appreciation for the interrelationships between human activity and its effects on the biosphere, have enlarged the scale of concern still further. The health of not only immediate human inhabitants, but also of the global geobiosphere, has become an issue. Figure 1-2 illustrate one attempt to summarize this enlarged conceptual framework for sustainable construction.
The "Apples and Oranges" Problem
The preceding discussion has described four progressively broader perspectives, or scales of consideration, in an attempt to address the issue of sustainability. The first looks at first costs of a structure. The second includes operating costs, but still from a strictly monetary viewpoint. The third (Figure 1-1) goes beyond first costs and operating costs to include cumulative energy and resource costs as well as monetary *
costs (which are inherently cumulative). The fourth (Figure 1-2) goes further still by incorporating issues of human and ecosystem health.
4. Protect Nature
Figure 1-2. A Conceptual Model for Sustainable Construction (Kibert, 1994, p.11).
Today the second of these perspectives has supplanted the first in common practice of building design to the extent that operating costs are reflected within conventional monetary valuation. Other elements of the more holistic perspectives are occasionally considered, typically on an ad hoc basis. A major difficulty in analyzing sustainability is with the many "externalites" that must be considered. Externalities are those costs which lie beyond the realm of conventional economic evaluation. One of the major challenges in providing a working theory for sustainability
is the development of a system of evaluation which "internalizes" all of these so-called externalities.
What is sometimes offered to fill this analytical void are grading schemes, where various concerns are listed and rated on an relative scale within each category. These categories are sometimes related to one another with weighting factors, in an attempt develop an overall score for a given building design proposal. While these schemes no doubt provide a useful service in raising the relevant issues of environmental concern, they are none-the-less problematic. The assignment of weighting factors between categories is often done without the benefit of any underlying theoretical basis.
EMergy analysis (spelled with an "M") is a theory and methodology developed by Howard Odum which provides unified system of valuation of natural and human economies. In this study, eMergy analysis is presented as the foundation for an analytical scheme to evaluate sustainability with regards to architecture. EMergy theory clearly asserts that money is a representation of only the human services required in bringing a commodity to market. This is obvious if one considers that nature is never "paid" for its services. Yet this is a concept that is often not clearly appreciated. This is related to the common misconception that human ingenuity and endeavor is the fundamental source of economic
value. Natural resources are in fact the fundamental source of economic wealth; human activity is the catalyst in the equation. Another major posit of eMergy theory is that nature does indeed have an economic system of its own, namely energy. EMergy recognizes different qualities of energy, and provides empirically-defined conversions, called transformities, between them. Furthermore, human economic activity is seen as a subsystem within the context of the larger natural economy, not as an independent or parallel system. Money is understood to represent a form of energy (namely human services), and with its appropriate quality (transformity) it can be evaluated on a common basis with other natural systems.
Solar energy is defined as the baseline level of energy quality and given a transformity of unity. The transformity of other types of energy represent a ratio of how much solar energy was directly and indirectly required in its production per unit of energy of the subject type. For example, one Joule of coal represents an investment by nature of 40,000 Joules of sunlight. Thus, coal is said to have a transformity of 40,000 solar emjoules per Joule (sej/J). Likewise, one US dollar in 1990 has been calculated to represent the equivalent of 1.6E+12 sej/$ (Odum, 1994b, p. 162) .
Focus of This Study
A complete evaluation of the sustainability of a proposed building design would address all of the issues outlined in Figure 1-2. EMergy analysis provides an unified basis for analytical evaluation of most (if not all) of the factors listed. This is discussed in further detail in Chapter 5.
This study begins with a literature review of industrialized building systems past and present. This provides a historical perspective on the on the concept of efficiency in building. Chapter 3 presents an eMergy analysis of various primary building materials. Chapter 4 presents three alternative residential design scenarios, which are analyzed in terms of first costs on an eMergy basis. Chapter 5 concludes the study by briefly describing the process by which eMergy analysis could be further applied to encompass operating cos:s and other considerations necessary in a more complete evaluation of sustainable design. It also relates these issues back to the relationship between sustainability and industrialized building.
CHAPTER 2 REVIEW OF LITERATURE
The history of industrialized construction is closely related to the history of the Industrial Revolution in general, and to the roots of the Modern movement in architecture in particular. Its roots go back as far as the early seventeenth century when the Dorchester Company of England produced demountable wood panel houses for the English fishing fleet in Cape Ann, Massachusetts (Holeman, 1980, p.6). While most of the story of industrialized construction (systematic building) takes place in Britain, the United States, and Europe; Japan made an early important contribution in the form of the Japanese house.
The Japanese House
Between the seventeenth and nineteenth centuries, Japan underwent a period of political isolation which resulted in a policy of conservation of resources including population, trade, and art. The architecture that developed during this time reflected these conditions in a spirit of economizing, rationing, and standardization. This Japanese architecture had a significant impact upon modern architecture of the
twentieth century, with a particularly strong influence on the work of Frank Lloyd Wright. It is of special interest today, because the environmental pressures Japan felt then mirror the growing recognition of global environmental strain today. This Japanese spirit for making the most of limited resources, and of creating an aesthetic of simplicity and efficiency, is one that much of the rest of the world would do well to emulate.
The floor plan of the Japanese house was based upon the organization of a number of Tatami mats. It was not a modular element, per se, but rather a part of a systematic approach to building. This mat, originally a portable element, is used to sit on, sleep on, and as a table. Made of rice-straw bound together with string, the mats are approximately 3' by 6', with a thickness of about two inches. The mat was originally designed to accommodate one man sleeping or two sitting. Room sizes are designed to accommodate a number of mats, with the constraint that corners of the mats are not allowed to touch. Figure 2-1 shows a number of Tatami arrangements. The most common size rooms are the six and eight mat rooms (9x12' and 12x12', respectively). Two different methods are used to relate the structure to the rooms: the 'maka-ma' uses a consecutive grid with the columns on gridline centers, while the 'kyo-ma' places a column-wide zone between room spaces. The heights of the room are also related by formula to the number of
mats, with different heights for an eight mat room, a six mat room, etc. _
4.5 MAT ROOM
6 MAT ROOM
3 MAT ROOMS
8 MAT ROOM
10 MAT ROOM
Figure 2-1. Room layouts based on Tatami mats (Russell, 1981, p.16) .
Another Japanese tradition that has gone on to be echoed in the theory of many industrialized building proponents is the idea of user participation in the building process. House building for the Japanese was not singled out as a special activity but seen as part of daily life in which any person can make their own house.
Early British "Pioneers of Prefabrication"
The British entrepreneurs of the early 1800's continued the practice of prefabricated housing for the market created by emigrants to the Americas, Australia, Africa, and the West Indies. The conditions which these colonists encountered
which encouraged the prefabricated housing solution included a shortage of skilled labor and a general lack of infrastructure for building construction, as well as a shortage of resources in some cases. Many settlers came with little more than a tent for shelter when first arriving in their new home. This left them vulnerable to the extremes of weather and to problems of theft. Those who came with prefabricated houses, ready for quick assembly upon arrival, were at a considerable advantage.
One of the more successful of the early models was the 'Manning Portable Colonial Cottage for Emigrants', marketed largely in Australia. It had several features that made it well adapted to the needs of its customers. First, it was specifically designed for mobility and ease of transportation. Manning designed it to "pack in a small compass" for shipping, and claimed "none of the pieces are heavier than a man or a boy could easily carry for several miles..." Second, it was designed for ease of erection. The only site work required was the building of the foundation and the assembly of components: "whoever can use a common bedwrench can put this cottage up." Third, it contained the essential qualities of industrialized construction, dimensional coordination and standardization: "every part of it being made exactly the same dimensions; that is, all the panels, posts, and plates, being respectively the same length, breadth, and thickness, no mistake or loss of time can occur in putting them together" (Herbert, 1978, pp.9-11).
Figure 2-2. Manning Portable Colonial Cottage for Emigrants, 1833. (A.) Frame (B.) Plan (C.) Detail of framing (Herbert, 1978, pp.10-11).
Figure 2-2 shows some of the details of Manning's design. The plan shows a 12' x 24 structure with two rooms 12' square each. It was a wooden post frame, members spaced at 3' intervals, which received standardized panels for
walls,doors, and windows. The Manning Cottage design was conceived of as a solution to the emigrant's need for "instant" temporary housing, at which it excelled. As a solution for permanent housing, however, it suffered from a problem that has often been the Achilles heel of the industrialized building climatic adaptation. As an Englishman, Manning was aware of the problems of cold and suggested installing a stove for heating. His single paneled walls, however, provided little insulation value. He showed even less recognition of the problems of heat, as experienced especially by settlers in Australia. "The 8-foot ceiling so cozy in England, created intolerable conditions when the external temperature soared to 100 degrees F, or more." (Herbert, 1978, p.23)
While Manning was advancing the concepts of industrialized building flexibility, ease of erection, mobility, standardization, interchangeability of components, and dimensional coordination he was still using a traditional material, timber, and the time-honored crafts of the carpenter and the shipwright. (Herbert, 1978) Some of his contemporaries, however, were beginning to look toward the new technology of iron construction in their development of prefabricated building. The first patent for the application of corrugated metal to building components was granted to Henry Palmer in 1829. The process of galvanization, patented in 1837, provided the material with its first effective protection from corrosion. A latter
patent, by John Spencer in 1844, greatly improved the manufacturing process of forming corrugated iron, making it available in greater quantities and lower cost.
Richard Walker purchased Palmer's patent and took on a pioneering role in its practical application. An advertisement by Walker from 1832 (Figure 2-3) shows a warehouse with barrel vaults of curved corrugated iron forming its roof. The use of corrugated iron for roofing solved a major problem; "...the roof had proved to be one of the intractable problems, not amenable to satisfactory solution using conventional materials..." (Herbert, 1978, p.35). The ability of this material span great distances economically was an advantage particularly to the construction of factories, warehouses, and other large industrial buildings. The application of prefabricated metal building systems predominantly to industrial buildings continues to this day.
Figure 2-3. Richard Walker, Warehouse, 1832 (Herbert, 1978, p.35) .
Walker also competed in the Australian emigrant market for portable buildings, and his sons, John and Richard carried on their father's business. By 1849, the California gold rush provided another significant, if short lived, market for their product. Edward T. Bellhouse was another British manufacturer of prefabricated iron buildings to participate in the California market, as well as American Peter Naylor of New York. Naylor "was perhaps the largest American manufacturer of prefabricated iron houses, shipping more than 500 houses to the West in one year" (Herbert, 1978, p.47).
With the demise of the California market, the British
returned to their traditional markets. Another firm
specializing in portable corrugated iron buildings for export
was that of Samuel Hemming. He produced residential and
commercial buildings, as well his most notable development,
the portable or temporary church. Not only did he offer a
wide variety of building type to fit various needs, but he
also began to show more sophisticated designs responsive to
the climatic conditions of his intended markets. A
contemporary account states:
The proprietor has himself been under tropical suns and in tropical rains; and his inventive genius provided for his son a house which should comprise portability, security, and be put up without any difficulty or trouble, by the most inexperienced hands .Mr. Hemming saw at once the capability of this principle of construction for adaptation to almost every conceivable want and climate... (Herbert, 1978, p.62).
While the claim of being adaptable "to almost every
conceivable want and climate' is definitely over-
enthusiastic, Hemming did offer "full glazed, half-glazed, louvered, and shuttered modular units, offering a wide variety of fenestration options" (Herbert, 1978, p.63) which were appropriate for his largely tropical market. Figure 2-4 shows some pages from the product catalog from Hemming's company.
One of the great works in the history of industrialized building was also born at the mid-century mark in Britain -the Crystal Palace by Sir Joseph Paxton. That subject will be discussed in greater detail in the next section. In 1854, Britain had yet another application for economical and quick-to assemble prefabricated structures the Crimean War. Isambard Brunei was in charge of some of the government1s initial designs for portable hospitals and tents. Brunei's father, Marc, was notable for his blockmill (for the manufacture of ship's pulleys), the first application of machine tools to mass production on a powered basis. Others including Hemming, Paxton and Charles D. Young also became involved in designing buildings for the war effort. The example of the British with prefabricated military buildings was later put use in the American Civil War where paneled prefabricated hospitals were used extensively (Herbert, 1978, p.96). The tradition of "Victorian prefabs" continued on through the late nineteenth century, notably in South Africa where settlers were lured by the discovery of diamonds (early 1870's) and gold (1880's).
EAST ISOIA V11.1. *
UHMMIKCTS PATENT IMPKOVBD IHJIITA1IIJR IIOl'SES.
mi wmmma. tun mt vmwma. mutol
Figure 2-4. Samuel Hemming's catalog, c.1854 (Herbert, 1978, pp.63-64).
Joseph Paxton and the Crystal Palace
Built in 1851, the Crystal Palace stands a landmark in the history of architecture. It was the first large scale building to be built using modular construction and prefabricated elements, and its list of innovations and accomplishments is no less impressive today than it was nearly a century and a half ago. The building was commissioned to house the first world's fair, The Great Exhibition of the Works of Industry of All Nations, in Hyde Park, London.
The building was to be temporary in nature, economical of materials and labor, simple in arrangement, capable of rapid erection, dismantling and expansion, illuminated entirely from the roof, built of fire-resistant materials and erected over an 18-acre site generally to a height of a single story (Kihlstedt, 1984, pp.132-33).
Its designer, Joseph Paxton, along with a staff, formulated the design eight days, and went on to build it in the unheard-of time of 39 weeks. It was dismantled in 1852 and re-erected at Sydenham Hill in 1854, where it stood until 1936 when it was accidentally destroyed by fire.
The building itself consisted of a steel and wooden structure clad in glass (Figure 2-5). Its dimensions were 1,848 feet by 408 ft, with an extension on the north side measuring 93 6 by 48 feet. Its central aisle was 72 feet wide by 66 feet high, and its vaulted transept was 72 feet wide by 108 feet high. It consisted of a series of hollow cast-iron columns joined by trussed girders that supported a roof made
of glass panes in a pleated, ridge-and furrow configuration. (Figure 2-6) The valleys of the roof were supported by gutters that collected the rainwater and delivered it through the hollow columns to underground drainage.
Figure 2-5. Paxton's Crystal Palace, c.1851 (Chadwick, 1961, p.130) .
Figure 2-6. Ridge and furrow roof of the Crystal Palace (Chadwick, 1961, p.127).
As an exemplar of the concept of industrialized construction, it is a tour de force:
1. designed to a 24 ft 0 in (7.32 m) structural and 8 ft
0 in (2.4m) cladding module (Figure 2-7)
2. components prefabricated, mass-produced and
3. dry assembly
4. many components interchangeable
5. rapid erection (39 weeks for 989,884 sq. ft (91,960
m) of floor space) and demountability
6. light steel structure with a weatherproof lightweight
skin, or curtain wall
7. the frame was its own scaffolding
8. the use of mechanized erection techniques, for
example the roof glazing wagon (Figure 2-8)
9. the designer, engineers and suppliers worked as one
organization. Paxton, Fox and Henderson (contractors and engineers) and Chance (glass supplier) between them controlled the companies working on the building (Russell, 1981, p.41)
Joseph Paxton was a farmer's son who since 1826 served as superintendent of gardens for the Duke of Devonshire. He worked as a gardener, a landscape gardener, and a landscape manager who also engaged in building design. This background played a crucial role in his development as a builder. Previous to his work on the Crystal Palace, Paxton had designed several greenhouses. It was in these projects where he developed his ridge and furrow glass roofing techniques and his familiarity with wood, glass and iron construction. Of perhaps even greater interest is the source of his inspiration for his roofing system, a lily by the name of Victoris regia (Figure 2-9):
Figure 2-7. Crystal Palace. (Left) Part of the south elevation showing cladding module of 8 ft (Right) Interior showing 24 ft structural module. Also shows the arch sections introduced to span existing trees; an early example of respect for site (Russell, 1981, p.41).
Figure 2-8. "Glazing wagons" utilized in roof construction (Russell, 1981, p.45).
This structural system, Paxton himself acknowledged, had been inspired by that of the plant which it was to house. The leaves of the great lily were formed of a flat upper surface supported by a series of webs like miniature cantilevers touching only intermittently; yet they would bear a considerable weight, as Paxton found when he put it to the practical test of placing his own daughter Annie, then seven, on one. (Chadwick, 1961, p. 101)
Figure 2-9. Victoris regia (A.) Paxton's daughter Annie on a leaf.(B.) The underside of a leaf at center, the inspiration of Paxton's roofing system (Chadwick, 1961, p.37).
Early American Contributions
While the British pioneered the ideas of portable prefabricated buildings and the application of corrugated iron, America was the primary scene of experimentation and development with other new building materials of the era -cast iron and steel. (The Crystal Palace just discussed is one very notable exception of British cast iron development.) Two key figures in the story of cast iron were both from New York; Daniel Badger and James Bogardus. Badger's factory produced parts for over 300 buildings in New York and throughout the United States between 1849 and 1877. Badger was unique among his peers in that he sold his products as
whole building concepts, systems of frame and skin. He manufactured his standardized components in New York and then shipped them to be assembled on site. Badger is also remembered for his finely illustrated product catalog. Bogardus is credited with the first all-iron building in the United States, his own factory built in New York City in 1849 (Figure 2-10). He would contract with various foundries and blacksmiths for the fabrication of building components and then supervise their assembly. Bogardus constructed several buildings on the East Coast from New York to Havana.
Figure 2-10. James Bogardus' cast iron factory (Russell, 1981, p.56).
In 1856, Henry Bessemer patented a new process for carbonizing iron to make steel. This was followed by methods for rolling and forming steel, and thus a revolutionary new building material was born. During the 1880's the development of steel-frame buildings was centered in the boom town of Chicago, Illinois. William le Baron Jenny was a key figure in the transformation from cast iron (First Leiter Building, 1879) to steel frame construction (Second Leiter Building, 1889/91). Steel-frame skeleton construction and the full story height 'Chicago window' became trademarks of the 'Chicago Construction'. Perhaps the largest personality of this Chicago style was Louis Sullivan. His Carson Pirie, Scott department store of 1899/1904 was "perhaps the most complete embodiment of what was to come" (Russell, 1981, p.64) with its emphasis on the grid of steel on its facades and vast glass area.
In 1908, Sears, Roebuck and Co. entered the prefabricated housing market through its nationwide mailorder business. With the establishment of their Modern Homes Division in 1911, the houses were marketed through a separate catalog complete with drawings, photographs, floor plans, detailed descriptions, and pricing. Home designs were offered in a variety of styles, sizes and price ranges. Stick frame construction was the rule; the company bought their own lumber mills in strategic locations to maintain cost-controlled supply sources. The homes came in packages of precut, numbered lumber and ancillary materials (nails,
paint, roofing, etc.) everything necessary for construction with the exception of masonry. Lighting fixtures and plumbing were popular options. Sears also introduced innovations including an early form of drywall in these homes. Financing was available directly through Sears based on their familiar time-payment plan. The decade of the 1920's, with its post-war optimism, was the heyday of the business. "The catalog grew thicker every year. By 192 6 it contained 144 pages, and quite a few of them in color. Over 100 different house models were featured..." (Snyder, 1985, p.44). The decline and eventual end of the venture was brought about by the Great Depression: not only did sales decline, but numerous foreclosures were required when mortgage payments ceased. By its end in 1937, Sears had sold over 100,00 mail-order homes.
Frank Llovd Wright
Out of the Chicago scene of the late nineteenth century, and out of Sullivan's office, came Frank Lloyd Wright. Wright was masterful in combining the values of his Arts and Crafts contemporaries with the ideas of the mechanized age. "He intended to imply not that the machine should be celebrated directly in mechanical analogies or images, but that industrialization be understood as a means to the larger end of providing a decent and uplifting environment for new patterns of life" (Curtis, 1983, p.78). Much of the inspiration for this synthesis can from his interest in
Japanese architecture. He admired its "refined proportions, the exquisite carpentry, the humble use of materials, and the subtle placement in nature. Moreover, this was an architecture which modulated space and charged it with a spiritual character: the opposite, in his mind, of the Renaissance tendency to put up walls around box-like closed rooms and to decorate them with ornament" (Curtis, 1983, p.78) .
From the late 1800's through roughly 1910, Wright developed a residential style which came to be called the 'Prairie House Type', which was perhaps his most influential contribution to modern architecture. Wright outlined his guiding principles as follows:
First. To reduce the number of parts of the house and the separate rooms to a minimum, and to make all come together as enclosed space so divided that light, air, and vista permeated the whole with a sense of unity.
Second. To associate the building as a whole with the site by extension and emphasis of all the planes parallel to the ground, but keeping the floors off the best parts of the site, thus leaving that better part for use in connection with the life of the house....
Third. To eliminate the room as box and the house as
another by making the walls enclosing screens the ceilings and floors and enclosing screens to flow into each other as one large enclosure of space, with inner subdivisions only. Make all house proportions more liberally human, with less wasted space in structure, and structure more appropriate to material, so the whole more livable...
Fourth. To get the unwholesome basement up out of the ground, entirely above it, as a low pedestal for the living-position of the home, making the foundation itself visible as a low masonry platform on which the building should stand.
Fifth. To harmonize all necessary openings to 'outside' or to 'inside' with good human proportions and make them occur naturally singly or as a series in the
scheme of the whole building. Usually they appeared as light screens instead of walls... there were to be no holes cut in walls as holes are cut in a box... Sixth. To eliminate combinations of different materials in favor of mono materials so far as possible; use no ornament that did not come out of the nature of the materials to make the whole building clearer and more expressive as a place to live in, and give the conception of the building appropriate revealing emphasis...
Seventh. To incorporate all heating, lighting, plumbing so that these system became constituent parts of the building itself. These service feature became architectural and in this attempt the ideal of an organic architecture was at work.
Eighth. To incorporate as organic architecture as far as possible furnishings, making them all one with the building and designing them in simple terms for machine work...
Ninth. Eliminate the decorator...
(Curtis, 1983, pp.80-81).
Figure 2-11 shows the plan from one of Wright's house from this period, the Willitts House of 1902. This illustration is from his Wasmuth Volumes, a portfolio of his work which became an important vehicle for his work to become known in Europe.
Of special interest here are his contributions in the
ideas of building systems and holistic architecture. Three
areas can addressed:
first, his attitudes to construction and materials and an interest in standardization; second, his approach to three-dimensional space in planning and its relation to dimensional grids; third his relation of the building to the site, and the manner in which he controlled the environment of his buildings both by this, and by mechanical means (Russell, 1981, p.77).
The Froebel toys given to Wright as a child by his
mother are known to have been instrumental in the first two
matters. They consisted of fundamental shapes cube,
cylinders, spheres and the toy structures were to be
carefully built, with a plan marked out first upon the floor. These toys have clear connection with Wright's attitudes to standardization and coordination and also his subtle use of square and tartan grids (Russell, 1981, p.78).
Figure 2-11. Plan of Wright's Ward Willitts House, Highland Park, 111, 1902 (Curtis, 1983, p.81).
Two examples of building systems by Wright include his concept for the American System Ready-cut prefabricated flats (1915) and the 'knitblock' system he used in some of his California houses of the 1920's. Wright also designed for prefabrication again much later with the Marshal Erdman Company in 1956. Shipping and assembling doubled the houses' costs, however, and they did not realize their goal of low-cost housing (Sergeant, 1984, p.146).
European system builders went on to pursue both standardization and dimensional grids, but they largely ignored his third and arguably most important contribution -his approach to the environmental quality of the building. It is his concept of the whole system holistic design -where environmental quality is integral, that is the rightful aim of systematic building design. And yet much of the history of modern architecture overlooks this:
To perfect a structural system which produces an uninhabitable building is only a partial system. Yet ihis is what many of the Europeans did. The latter learned many lessons from Wright, but it seems that often these were of the most superficial sort and we will find in the ensuing development of building systems that repeated attention was given merely to structure and fabric in very narrow terms indeed, usually ignoring che implication of climate, site, and internal comfort (Russell, 1981, p.83).
While Wright strove to integrate technology with human needs in what he called organic architecture, the Europeans of the early twentieth century were fixated on what
came to be called the 'machine aesthetic'. Their goal was the creation of an architecture that was appropriate for their age the age of Frederick Winslow Taylor's work study methods and Henry Ford's phenomenally successful assembly line production. The leading vanguards of this new architecture were Le Corbusier, Walter Gropius, and Mies van der Rohe.
One of Le Corbusier's earliest proposals for mass-produced housing was the Domino House concept of 1914 (Figure 2-12). This was envisioned as a way to respond to the problem of reconstruction following the First World War, which had just then begun. In his words, this concept "would result in a completely new method of construction: the windows would be attached to the structural frame, the doors would be fixed with their frames and lined up with wall panels to form partitions. Then the construction of the exterior walls could begin" (Russell, 1981, p.126). In the Domino house one can see the seeds of many of the ideas that would go on to become the fundamental elements of modern architecture and industrialized construction: standardization, component building, user participation, the flexibility allowed by the open framework, moveable partitions, freedom in the facade design. Le Corbusier later crystallized these concepts into what he called his 'Five Points of a New Architecture' :
1. the piloti, or vertical support,
2. the plan libre (free plan), allowing interior wall
placement independent of structural support (provided by the piloti),
3. the facade libre (free facade), also a result of the
piloti as support,
4. the fenetre en longueur (strip window), really a
subset of the free facade, and
5. the toit-jardin (roof garden), intended as a
replacement of the land lost underneath the structure. (Curtis, 1986, p.69)
Figure 2-12. Le Corbusier's Domino House concept, 1914 (Curtis, 1986, p.43).
While Le Corbusier's descriptions of his new architecture often talk about their environmental advantages, the rhetoric often did not match the reality. His strip windows, for example, were intended to provide superior daylighting over more traditional openings. Instead, they were often sources of problems in interior comfort, allowing overheating in hot conditions and thermal loss in cold weather. The flat roofs of the "international style" are notorious for problems with leaking in the rain (a problem that many of Wright's buildings shared). Even with his later
brise-soleil (sun breaker) Le Corbusier shows a type of band-aid approach to designing for climate. The concrete struts may have blocked the direct sunlight, but they themselves became solar heat sinks due to their thermal mass.
Despite its shortcomings in regards to holistic design, the importance of Le Corbusier's contribution to modern architecture is beyond doubt. His book Vers une Architecture --Towards an Architecture (frequently mistranslated "Towards a New Architecture")--is one of the most influential architectural books of this century. First published in Paris in 1923, it states in poetic form the ideas and theory behind his work; for example:
A great epoch has begun. There exists a new spirit.
Industry, overwhelming us like a flood which rolls on toward its destined ends, has furnished us with new tools adapted to this epoch, animated by a new spirit.
Economic law inevitably governs our acts and thoughts.
The problem of the house is a problem of the epoch. The equilibrium of society today depends on it. Architecture has for its first duty, in this period of renewal, that of bringing the revision of values, a revision of the constituent elements of the house.
Mass-production is based on analysis and experimentation.
Industry on the grand scale must occupy itself with building and establish the elements of the house on a mass-production basis.
We must create the mass-production spirit. The spirit of constructing mass-production houses. The spirit of living in mass-production houses. The spirit of conceiving mass-production houses.
If we eliminate from our hearts and minds all dead concepts in regard to the house, and look at the question from a critical and objective point of view, we shall arrive at the "House-Machine", the mass-production house, healthy (and morally so too) and beautiful in the same way that the working tools and instruments which accompany our existence are beautiful.
Beautiful also with all the animation that the artist's sensibility can add to severe and pure functioning elements.
(Le Corbusier, 1931, pp.6-7)
While most schools of the period remained loyal to the beaux-arts tradition, Walter Gropius and the Bauhaus embraced the new design philosophies of the machine age. At the Bauhaus, the ideas of unity, wholeness and totality were a powerful force and these quasi-religious ideas became translated into architecture theory. Ironically, it is in their interpretation of these holistic concepts that the seeds of perhaps their greatest disservice to environmental design lay. For Gropius, the building itself was the whole. In this conception, the building was separated from its context -its specific locale and environment and viewed as an artifact in and of itself. "Accurately named the 'International Style', it had set aside the normal concern of the architect for the people and their differences, and for places and their differences and substituted the idealizations of machine technology" (Russell, 1981, p.137). From the perspective of a modern day systems theorist, the idea of the relations of parts to the whole is still a valid one, it is just that Gropius defined the "the whole" at a remarkably narrow scale. Today we recognize "the whole" as
the global scale of the earth's biosphere. In this context,
the proposition of the building, and indeed the architect, is
a vastly different one.
Nonetheless, the impact of Gropius and the Bauhaus on
the development of the modern machine aesthetic was
important. A series of projects at the Bauhaus examined the
implications of standardization and functionalism. Among
them were Gropius' Serial Houses of 1921, which had the goal
of combining maximum standardization with maximum
variability. Georg Muche in 1926 designed a prototype steel
house with flexible floor plan and potential for expansion.
Ludwig Hilberseimer in 1932 proposed a plan for the city of
Dessau that was very similar to the approach later adopted by
Levitt Brothers for their tract housing in the United States
(Figure 2-13). As with Le Corbusier, Gropius's rhetoric did
not match the reality that followed:
...Standardization of the building elements will result in new housing units and sections of cities having a uniform character. There is no danger of monotony, for if the basic requirement is fulfilled that only the building units are standardized the structures thereof will vary. Their "beauty" will be assured by properly used material and clear simple construction...(Russell, 1981, p.144).
Both Le Corbusier and Gropius during this period, "virtually excluded environmental comfort and services from their call for new attitudes to technology..." (Russell, 1981, p.145).
Ludwig Mies van der Rohe is another key figure of the modern movement associated with the Bauhaus (which he led in its final years before closing in 1933). Mies is noted for his concepts of modular anonymous space based on a meter grid
and the'separate of structure from space-making elements (i.e. walls). The Bauhaus model of a house style firmly equated several keywords into one interlinked concept: mechanization, standardization, dimensional coordination, mass production, efficiency, low cost working class housing.
Figure 2-13. Plan for Dessau, Ludwig Hilberseimer, 1932 (Russell, 1981, p.144).
Even today this list is often repeated as a model for cost-conscious housing. To this list, however, Gropius added one crucial factor the independence of the house from its site "The houses as designed are independent, coherent organisms not tied to any site, devised to fit the needs of modern
civilized man in any country, not even only Germany." (quoted in Russell, 1981, p.147). It is this idea that must be exorcised from the theory of industrialized housing.
Later in his career, Le Corbusier's work did evolve beyond his earlier mechanistic forms and became more interested in regional identity and connection with nature. Integral to this new focus was his development of a proportional system called the 'Modulor'. "The Modulor was more than a tool; it was a philosophical emblem of Le Corbusier's commitment to discovering an architectural order equivalent to that in natural creation" (Curtis, 1986, p.164). It was supposed to be 'a harmonic measure to the human scale, universally applicable to architecture and mechanics' (Curtis, 1986, p.163). Figure 2-14 illustrates the concept: a six foot man with his arm upraised is inserted into a square, which in turn is subdivided according to the Golden Section. Smaller dimensions are generated by the Fibonacci series (each number the sum of the previous two) .
Le Corbusier used the Modulor system in much of his post-war work. An important example is the Unite d' Habitation at Marseilles, where it was utilized to regulate the relationships between the large and small elements of the facade design. The Unite also contained Le Corbusier's other new devices, the brise-soleil and be ton-brut. As mentioned earlier, the brise soleil represented Le Corbusier's new awareness of (if not an altogether satisfactory response to) solar heat gain. The Unite itself became a prototype for
collective housing. "In retrospect one realizes that the Unite, along with Mies van der Rohe' s very different but nearly contemporary glass and steel towers, was one of the parent buildings of the post-war modern movement" (Curtis, 1986, p.163) .
Figure 2-14. Le Corbusier's Modular (Curtis, 1986, p.164).
Another European interested in industrialized housing was the French designer and metal fabricator Jean Prouve. Unlike Le Corbusier and Gropius, however, Prouve was strictly a pragmatist. One of his most interesting creations was his large moveable internal partitions with spring fixings, as used in the La Maison du Peuple. Another is the Free
University of Berlin. It uses all the rules of industrialized building: free facade, adjustable infill panels, etc.. In it, the concepts of growth, change, and indeterminacy are prominently displayed. Prouve did not considered himself an architect, instead being described as a 'self-styled constructeur' (Russell, 1981, p.158). Another significant figure in the history of industrialized architecture who did not arise from the architectural profession is the subject of the next section, the American R. Buckminster Fuller.
R. Buckminster Fuller
The ideas of Richard Buckminster Fuller form an important contribution to the field of industrialized building, for he approached the subject from a uniquely scientific and technological perspective. His first involvement in building construction was with his father-in-law; together they created the Stockade Building System. Between 1922 and 1927 they built 240 buildings using this system, which consisted of lightweight blocks made of straw and cement. It was during this time that he formulated his attitude to building:
That was when I really learned the building business, and the experience made me realize that craft building -in which each house is a pilot model for a design which never has any runs is an art which belongs in the middle ages. The decisions in craft-built undertakings are for the most part emotional and are based upon methodical ignorance (Russell, 1981, p.177).
In 1927, when as Fuller says, 'I resolve to do my own thinking' (Russell, 1981, p.175), he began to frame his ideas about the use of machine technology. The first fruits of this labor are seen in his so-called 4D houses, a 10-deck house design and the famous Dymaxion house. The 10 deck house featured a streamlined shield to bring the building's heat loss proportional to the air drag, which Fuller claimed could reduce heat losses to very little. The Dymaxion house was Fuller's first proposed solution for the problem of low-cost housing. It was inspired by his desire to create an extremely efficient dwelling that could be built quickly and inexpensively, with the intention of being mass produced for the retail price of $1500 (roughly the cost of a typical American automobile). The 4D house is a one-story hexagonal volume suspended from a central mast which also functioned as a service core (Figure 2-15). The design was completely futuristic, demanding materials and standards which at the time could not be met, and yet it did much to stir the public imagination.
One of the ideas to come out of the Dymaxion house was Fuller's mass-produced, self-contained bathroom. Twelve prototypes of the unit were produced in 1936, but it was never produced in quantity. The idea of the "plug-in" pod, however, has lived on. In the early 1940's Fuller developed the Dymaxion Dwelling Machine, or Wichita House as it came to be known.
Figure 2-15. Fuller's 4D Dymaxion house, 1927 (Ward, p.71)
In this design he put into practice his ideas for using shape to control cooling requirements. The building incorporated a ventilator which used natural external air flow and convection currents to keep the interior temperature comfortable even at outdoor temperatures of 100 degrees F
(Russell, 1981, p. 181). Two prototypes were built, but because of the massive tooling costs which in turn required a large continuous guaranteed market, the design was never mass-produced. One of concepts, however, has been realized in mass production.
After the Wichita House project, Fuller went on to invent the geodesic dome by devising a means for executing an enclosure that was simple and easily adaptable to prefabrication methods. The geodesic dome is a structure with an ability to span great distances with an economy of material, making it particularly applicable to large-scale buildings of many types. It combines the gravity-resisting shape of a solid dome shell with the economy of material of a three-way triangulated truss.
While Buckminster Fuller's work has been important in the area of industrialized building, most of it has never reached the mainstream of public acceptance. Perhaps Fuller's greatest contribution to architecture was not in the artifacts he produced, but in his "fundamental studies of a problem and his reformulating of possible directions"
(Russell, 1981, p.184).
More American Developments
Another American to play an influential role in the development of industrialized construction, particularly in the area of modular coordination, was Albert Farwell Bemis. Bemis put forward his ideas in a three volume work, The Evolving House, between 1933 and 193 6. Volume I is subtitled A History of the Home, while Volume II contains 'an analysis of current housing conditions and trends and comparisons with other industries' (Russell, 1981, p.185). It is Volume III, Rational Design, in which he puts forth his most lasting contribution the proposal of the 4 inch cubical module matrix (Figure 2-16). "Bemis saw his cubical module as the 'focus for standardization' and points out how all the parts of the house, whether factory made, or made on site, could relate to it" (Russell, 1981, p.191). Bemis' proposals for the use of this coordinating module were quickly taken up in the United States, and were subsequently adopted by Europe's proponents of component building in their metric equivalent (100 mm).
Following World War II, the United States government took an active interest in addressing a nationwide housing shortage, and provided funds for the development of factory built housing. One of the most publicized products of this program was the Lustron House, designed and manufactured by Carl Strandlund in 1946.
Figure 2-16. The 4 inch cubical module matrix: Albert Farwell Bemis, 1936 (Russell, 1981, pp.186-187)!
The house was made of prefabricated steel panels with a porcelain enamel finish. It had a steel stud structure with
the panels employing rubber gaskets and fiberglass insulation. Technically, the house had few problems, yet the project ended in failure. Lustron was given the Curtiss-Wright aircraft factory at Columbus, Ohio, and a series of government loans. Production began in 1949, only to close in 1950 after producing 5000 units due to marketing and political difficulties. Chief among these was the customer's requirement to pay the total $6000 amount up front due to financing difficulties. The failure of the Lustron Home project provided a valuable lesson for later building systems designer's--that the whole process of home provision, including financing, building regulations and other factors beyond the technical design of the structure itself, must be considered.
While the failure of the Lustron house brought about calls for the abandonment of the goal of mass-produced housing--'If Lustron doesn't work, let us forever quit talking about the mass-produced house': Senator Ralph Flanders (Russell, 1981, p.295)--the west coast designer-architect Charles Eames breathed new life into the idea of the industrialized vernacular with his Santa Monica house of 1949. Its simple form of rectangular units characterized an open system of off-the-shelf prefabricated components. Its materials of light metal structure and colored panels and glass invoked the image of a Mondrian painting, while its open plan allowed flexibilities in spatial organization and a continuum of lifestyle changes over time (Wilkes, 1988b,
p.10). It was also able to achieve the economic advantages of industrialized construction, so often proclaimed but often not realized. The successful combination of function and aesthetics of the Eames house won the admiration of the design community, and kept the dream of the machine aesthetic alive.
Carl Koch has been involved in a number of concepts for industrialized housing during his career, starting with his participation in the Lustron House Project. In 1947 he designed the Acorn House, which arrived on site with its floor, roof and walls folded against a central utilities core. Made of steel and timber construction, it was placed on a prepared foundation and then unfolded. His Techbuilt house of 1953 is perhaps his most famous work. The house is a two-story design constructed of stressed skin plywood panels on a 4-ft module (Figure 2-17). The basic exterior frame erection was accomplished in a two-day time period with two to four workers. The design also came with an instruction manual to allow for owner assembly. The Techbuilt house was unlike many earlier proposals for industrialized construction in that it did not strive for the machine aesthetic look. While the cathedral ceilings of the second floor were something of a new look, still it blended easily with existing architecture. This, along with its cost competitiveness, is probably the primary reason it was unlike many of its predecessors in another important way -commercial success. The product was franchised and its
market stretched across the United States and abroad; Techbuilt Homes is still in business today. Koch went on to concentrate his later work in prefabrication in the material of precast concrete with the Techcrete system.
Figure 2-17. Techbuilt House, Carl Koch, 1953 (Russell, 1981, p.596) .
In 1961, Konrad Wachsmann authored an influential document on industrialized building called The Turning Point of Building. Born in 1901, Wachsmann had a long history of involvement in the field. Starting out as a cabinetmaker and carpenter, he became the Chief Architect to Europe's largest prefabricator of timber components in Germany. After working with Le Corbusier for a period in France, he emigrated to the United States in 1941, where he joined Walter Gropius in designing the Packaged House System and founding the General
Panel Corporation. His Molibar Structure of 1944, featuring
a large space frame roof in tubular steel, was shown at the
Museum of Modern Art. In 1950 he became a Professor at the
Institute of Design at the Illinois Institute of Technology
(Russell, 1981, p.316).
In The Turning Point of Building, Wachsmann repeats many
of the familiar arguments in favor of industrialized
building. Nonetheless, "the very coherence of the Wachsmann
argument, has been tremendously influential both on building
systems and on architecture at large. The longspan, large
shed, flexible interior, environmentally controlled spaces of
Ehrenkrantz, Rogers and Foster all owe much to these
propositions" (ibid. 319). Wachsmann, perhaps more than
anyone else, popularized the space frame. He shows that long
before Fuller, Alexander Graham Bell demonstrated structural
systems based on the tetrahedron (Figure 2-18). Wachsmann's
most innovative contribution to the idea was his development
of the joint, which he described as 'a manifestation of
energy' (Figure 2-19).
While Wachsmann's work provided some new insights toward
the industrialized building that was to follow, it also
unfortunately repeated and even amplified the call to ignore
climatic design considerations in building:
While the production of synthetic building materials is already providing us with insulation capable of smoothing out local climatic conditions so effectively that it is useful in the face of both extreme heat and cold, complex mechanical air conditioning equipment is making it possible to ignore the degree of latitude, and the local climate in general, as a direct influence on construction. Mechanical equipment of this kind helps
to create autonomous space that manufactures its- own climate. Accordingly, no design need necessarily be determined by climatic conditions. The anonymous, universal room thus becomes a reality (Wachsmann, quoted in Russell, 1981, p.323).
Figure 2-18. Alexander Graham Bell and tetrahedral-based structures, c.1900 (Russell, 1981, p.320).
In retrospect, it is hard to comprehend how such 'anonymous, universal' spaces, devoid of any local character, were actually seen as a fervent goal. In his book, Wachsmann puts forth Paxton as one of his great inspirations, calling his
Crystal Palace a work of art. Yet he has, in the tradition of his mechanistic contemporaries, completely distorted many of the lessons of this predecessor. "For Paxton, each problem had a unique solution, each situation demanded a new response, which we might call holistic eclecticism" (Russell, 1981, p.320). At the same time, his deeper understanding of the importance of the joint quite ironically signals an unconscious, nascent move toward an 'ecological' philosophy. For an ecological viewpoint holds that it is the relationships between objects the connections, the joints -which are more important than the objects themselves.
Figure 2-19. Wachsmann's multi-way space frame joint, 1950's (Russell, 1981, p.324).
The School Component Systems Development (SCSD) system was proposed by Ezra Ehrenkrantz in 1961. The SCSD system was developed with the intent of supplying 22 school projects throughout 13 California public school systems, and was
funded in part by the Ford Foundation's Educational Facilities Laboratories. SCSD was different in concept from most of its predecessors in that it was designed as an open system comprising only about 50% of the total building. It consisted of four subsystems: structure, lighting and ceiling, partition, and mechanical. Each of these subsystems were put out to bid by independent manufacturing concerns. Beyond these components, the rest of the project was the task responsibility of the local project architect, who was free to adopt the building to the site, including the choice of external cladding materials.
The concept of the advantages of an open system marked an important shift in the mentality of systems designers. "Ehrenkrantz... showed that the mass production argument does not mean vast closed systems with guaranteed markets: indeed, the indications were that, in many ways, this was a disadvantage to develop" (Russell, 1981, p.530). The Educational Facilities Laboratory added this: "Basically it is a means of using the efficiency of modern industrial production to construct schools, while still avoiding standardized plans or monotonous repetition of either rooms or general appearance" (Russell, 1981, p.531).
Following in the footsteps of the SCSD system was Toronto's study for Educational Facilities (SEF) project. Their Metropolitan School Board had shown great interest in the SCSD system, and in 1965 approved the study, again with funding from the Educational Facilities Laboratory in New
York. Like SCSD, SEF was an open system plan, but it included 10 subsystems accounting for 75-85% of the building value as opposed to SCSD's 4 subsystems for 50%. The subsystems included: structure, HVAC, lighting-ceiling, interior partitions, vertical skin, plumbing, electric-electronic, caseworks-furniture, roofing, and interior finishing.
SEF is more notable for its development of a systems approach than its actual buildings. This approach included: "the academic and administrative programming; the interpretation of this programming into detailed performance specifications; the tendering procedures; the bid evaluation methods; the two-stage contractual system; and the management system for design, construction, and evaluation of the individual school projects" (Sullivan, 1980, p.95). The "dual-contract procedure" separated component manufacture from construction. "The SEF Project culminated in the first successful completely open building system in construction history generated in a single bid" (Sullivan, 1980, p.95).
At the 1967 Montreal World's Fair, Moshe Safdie showcased a housing concept called Habitat. Its basic system consisted of repetitive load-bearing reinforced concrete box modules forming a variety of house types (Figure 2-20) Its complex organization was designed to provide a multilevel neighborhood incorporating a variety of community facilities. Habitat was both admired for its aesthetic design qualities and criticized for its huge cost overrun problems.
Originally planned for 900 units, only 158 were constructed, with costs averaging between $80,000 and $100,000 per unit (Wilkes, 1988a, p.12). Safdie points out that the project scale reduction tripled the unit costs, and thus are not representative of what the technology is capable of. Habitat also featured prefabricated fiberglass bathroom modules and an innovative pedestrian street network incorporating mechanical distribution.
The Institutionalization of Industrial Building in Britain
Perhaps nowhere has the concept of industrialized building taken hold stronger than in Britain. The British were the originators of prefabricated buildings, as discussed
earlier, and following the second World War, the concept became largely institutionalized. In 1944, the government passed Housing Act, which created a temporary housing program that built 156,667 houses between 1945 and 1948. In overall terms, the program was not a great success; cost overruns and overstated benefits tended to give prefabrication a bad name. Yet lessons were learned and the ideal of mechanized building lived on.
The most famous of the housing concepts under this program were by a firm of designers called ARCON (Architectural Consultants), with Edric Neel, Rodney Thomas, and Raglan Squire as principals. One of their projects was the design of a kitchen/bathroom service core following the example of Buckminster Fuller's Dymaxion bathroom. The rectangular unit contained kitchen appliances on one side and bathroom facilities on the opposite side. This original design was never mass-produced, but the concept was later incorporated into the ARCON house design. The ARCON house underwent a series of design changes before going into production in 1945. The ARCON Mark 5 house consisted of about 2 500 parts produced by 145 different manufacturers; 41,000 units were produced in the three years of the program. It "incorporated many ideas that only much later were to become standard practice in housing in Britain. Among these were ducted warm air heating, modular kitchen fittings, prefabricated electrical wiring harness, prefabricated floor and ceiling panels, and a high standard of insulation in
walls and ceilings" (Russell, 1981, p.243). Thus, here is an all too uncommon case where the environmental comfort of a prefabricated design actually exceeds that of the common vernacular of the time. The example of the ARCON Mark 5 house also points out another continuing problem in the area of prefabricated housing. Although the 'prefabs' were environmentally better than most houses of the time, they did not conform to the building regulations and were required to obtain a special wavier before being allowed to be built. This points out the problem of regulations that deal with the way things are made, rather than the standards to be achieved.
When the government decided to cease support of the temporary housing program, ARCON turned their attention to other projects. In the early 1950's they developed the ARCON tropical roof using a tubular truss and columns (Figure 2-21). It had a double roof to allow air circulation for cooling, and met the need for a lightweight, easily erected structure for large spans. In addition to their development work, ARCON also carried out research projects into specific problems. In research concerning component interchangeability, jointing, and dimensional coordination, Rodney Thomas' work led to the realization that the joint was much more important than the component.
While groups like ARCON were dealing with industrialized construction for housing following W.W.II, the Architect's Department at Hertfordshire was applying the idea to the need
for new school buildings. It proposed a method of building with the following principles (Russell, 1981, p.255):
1. rapid erection
2. economical, but not cheap, building
3. repair and maintenance costs comparable with those of
4. a flexible system: this was not interpreted as the
ability to make frequent of rapid changes within the building envelope but much more it was seen as removing one of the main obstacles to planning freedom and allowing each building to be individually tailored to its site.
5. the schools produced should be 'pleasing to look at
and to work in'
Figure 2-21. Tropical Roof, ARCON architects, early 1950's (Russell, 1981, p.246).
A prototype was built at Cheshunt in 1946, consisting of a light pin-jointed steel frame, concrete roof panels laid dry, honeycomb partitions, and horizontal precast concrete units for the external walls. A key part of their philosophy
was the use of the planning 'grid. Initially, they utilized frame construction based on the bay system. This required a given range of spans, and allowed for expansion by adding more bays. This was later replaced with the two-way grid method, where columns could take any position on a regular grid, and have beam connections from any or all four sides. The two-way grid method was more flexible, which could be used in dealing with orientation and site problems (Figure 2-22). Another important change was from their initial 8 ft., 3 in. grid to one of 40 inches.
By 1956, Hertfordshire offered three structural systems with interchangeable components: brick, steel, and concrete. The 1949/50 program even included a timber-framed system which was a response to steel shortages. Thus they, unlike many of their fellow systems builders, were pragmatic rather than dogmatic about the use of "industrial materials". Two other aspects of their work which went against the grain of building systems dictums were relatively little bulk purchasing and the use of "wet" construction wherever it was considered sensible. Unlike the government's temporary housing program, the success of the Hertfordshire work did much to establish the credibility of the factory mass production ideal.
Industrialized construction continued to evolve in the education market with the creation of CLASP, the Consortium of Local Authorities Special Program, in 1957 (Figure 2-23).
ON THIS SITE A RECTANGULAR PLAN WITH GOOD ORIENTATION MEANS
THIS SECTION OR EXCESSIVE SITE WORKS
ON THIS SITE A RECTANGULAR PLAN TO GIVE GOOD ORIENTATION
THIS SECTION OR EXCESSIVE SITE WORKS
A RECTANGULAR PLAN WITH THE CONTOURS GIVES POOR ORIENTATION
THEREFORE SOME IRREGULAR PLAN FORM IS CALLED FOR
A RECTANGULAR PLAN WITH THE CONTOURS GIVES EAST WEST ORIENTATION
THEREFORE A PLAN OF THIS TYPE IS NEEDED TO FULFILL CONDITIONS OF SUN AND SLOPE
Figure 2-22. Using system flexibility to deal with site problems (Russell, 1981, p.264).
They made their most important mark with the award of the 1960 Special Grand Prize at the Triennale di Milano for the
primary school erected there. The school aroused a great deal of interest from Europe in the British approach to school design and CLASP in particular. Actual cost reductions were a good part of the interest: "the 1948 cost per school place L320: the increased cost of materials would have made this L550 in 1960 (the year of the exhibition) whereas in fact the actual cost was L260..." (Russell, 1981, p.403) .
Figure 2-23. CLASP, 1957 onwards, dimensional system (Russell, 1981,
Isometric showing p.395) .
It is pointed out, however, that these comparisons may be misleading. A great deal of the cost savings was achieved through the use of multi-use spaces, thereby reducing the overall floor area considerably. Thus, prefabrication itself may not be the primary reason for the cost reduction, but rather the different approach to the design problem.
The success of CLASP began to change the climate into which the ideas of industrialized building were received. CLASP gradually developed throughout the 1960's and 70's to include buildings of many types, from health centers to community centers to universities (University of York). Yet, after years of system building, professional and public criticism persisted. In its Annual Report for 1975, CLASP reports:
Some elements of the construction industry criticize system building on the grounds that it is a short cut technology, a bureaucratic convenience, and a struggle to achieve the cheapest building regardless of cost and regardless of environmental consequences (Russell, 1981, p.413) .
Yet another method of system building was initiated in the War Office in 1961, but soon thereafter (1963) passed on to the Ministry of Public Buildings and Works (MPBW) (Figure 2-24). Named after administrator David Nenk, the NENK concept was organized around eight criteria (Russell, 1981, p.420):
1. Dimensions of all spaces and thicknesses of walls,
partitions, floors, and roofs would be multiples of the basic module (M) which was 4 inches or 10 cm (approx.).
2. Submodular thickness would then be considered and
preferred sizes for components decided.
3. Structure based on the use of a space frame.
4. The carcassing of internal and external walls,
floors, and roofs would be considered independently of their finishes.
5. External walls and partitions would be in vertical
panels spanning between floors and ceilings.
6. External walls and partitions to be made up of two
independent leaves thus allowing differing combinations to achieve differing performance requirements.
7. Services to be housed in roofs and floors and in wall
8. Dry construction to be used wherever practicable.
Figure 2-24. NENK system Isometric showing hypothetical assembly (Russell, 1981, p.419).
The use of a space frame was an attempt to escape the difficulties and span limitations imposed by the post and beam frame. It was a double layer flat grid space frame made up of prefabricated inverted tetrahedra. While Fuller's work with tetrahedra is no doubt the original inspiration for the
space frame, it was Konrad Wachsmann's work, showcased in his
1961 book The Turning Point of Building, that probably had
the most influence on designers of this period. The use of
the 4 inch module as the basic sizing and positioning
dimension grew out of a concern to separate the planning grid
from the structural grid. One interesting idea put forward
by the NENK team was that of the number trio: for example,
with only three panel widths of 5M, 6M, and 7M it was shown
to be possible to produce every modular dimension from 10M
upwards, in an increasing number of different ways. Thus the
idea of maximizing flexibility with a minimum of parts was in
some measure realized.
The decision to consider the finishing materials of the
walls, roof, and floor independently of the basic
construction is another interesting point:
At least there is a recognition here that the curious moralities of the machine age argument as it had applied to the use of materials, and the 'honest' expression of functions and means, were more a hindrance than a help if 'Industrialized Building' was to begin to match the choice and flexibility of conventional building and also to remain economically viable.... The attempt in NENK to offer the opportunity for the use of conventional materials and/or industrially produced materials can here be seen against the commonly held view that to be industrialized a system has certainly to look industrialized (Russell, 1981, p.425).
Documentation was also given considerable attention in the NENK system. "Each component and junction was drawn separately and given a discrete code number and all drawings were reduced to A3 size to form a basic manual for the method" (Russell, 1981, p.425).
A number of buildings were produced with the system, but inertia waned and when key supporters moved on (Iredale to work for Ehrenkrantz in the United States) it was gradually phased out. Even though the NENK system had begun the transformation from the idea of closed to open systems, it was not enough to achieve lasting success.
Along with all the other governmental agencies involved in industrialized building in Britain in the 1960's, the Ministry of Housing and Local Government (MHLG) also developed a system for housing starting in 1961. Based on the 1 ft. 8 in. planning grid developed by CLASP, it went by the name 5M. It used a steel frame with timber beams and a flat roof 'to give flexibility in the shapes of the houses', although in practice the variety of shapes produced was small. Early on the group experimented with using components developed for CLASP, only to discover that they were over-designed and thus to expensive for housing purposes. It also tried some unusual solutions for a lightweight party wall, including a design incorporating a lead curtain to assist in sound reduction.
In order to designers estimate costs, MHLG produced The 5-Minute Guide to Economic Design in 5M System Housing in 1966. This document contained a series of examples based on the simple logic that those designs with the fewest corners, and most square shape would be most economical. Similarly, for row housing, as the number of attached units went up, the per unit cost would drop. While these facts are no doubt
true, it overlooks the myriad of other factors that come into
play in the cost of good human design.
It is interesting to note that as the concerns of energy and conservation generally became more central to building design, much housing again acquired a style involving projections, steps, staggers and pitched roofs of all sorts. One set of rationalizations replaced another, and a different range of expressive forms has begun to emerge. This shows the dangers of assuming that humane environments arise merely from satisfying a narrow range of criteria (Russell, 1981, p.437).
The 5M program was officially terminated in 19 68, with little to claim in the way of accomplishments. In addition, the maintenance record for a number of the houses built with the system is poor. A problem with concrete panels infilling the steel frame breaking up and falling out is reported in a number of cases, with expensive repair bills, after little more than a decade of use.
Following closely behind the example set by CLASP, the Second Consortium of Local Authorities (SCOLA) was formed in 1962 with a set of goals much the same as those seen before: a kit-of-parts solution for various requirements, standardization for the benefit of quantity production, consolidated projects for bulk purchasing, and fast construction times. The member counties of SCOLA, however, was more widely spread over England. The SCOLA group developed yet another closed building system, and showed a curious disregard for learning from the experience of previous systems builders. In an even greater anomaly, one member county, Hampshire, applied the system to a
standardized whole plan for several of its school sites, thus undermining the basic concept of adaptability through a flexible system. To its credit, the SCOLA group further pushed the movement to a more open system framework, and made advances in the process of documentation and communication involved with such bureaucratic systems. Like many of the other system designs of its day, however, SCOLA schools have had a poor record in regard to maintenance and energy.
The concept of the local authority client sponsored consortia grew throughout the 1960's in England. By 1970 these consortia accounted for over half of the total school building program (Russell, 1981, p.518). By 1976, the list of consortia included the following (Russell, 1981, p.520):
ASC: Anglican Standing Conference
CLASP: Consortium of Local Authorities Special Program CLAW: Consortium Local Authorities Wales MACE: Metropolitan Architectural Consortium for Education
METHOD: Consortium for Method Building
ONWARD: Organization of North West Authorities for
Rationalized Design SCOLA: Second Consortium of Local Authorities SEAC: South Eastern Architects Collaboration
Each of these groups developed their own approach to systems
building, with very little interchangeability between them.
Over time, problems of maintenance, poor environmental
control, aesthetic disfavor, and a reduction in demand
brought about a gradual abandonment of these closed systems
No doubt influenced by the adaptation of industrialized building by the British and other European governments, as well as the success of SCSD in California, the United States government undertook its largest involvement ever in prefabricated housing with Operation Breakthrough. Directed by Housing and Urban Development (HUD) administrator George Romney in 1969, the program's objective was to 'improve the process of providing housing' (Wilkes, 1988a, p.12). Over 600 proposals were received, and in February 1970, 22 were accepted.
The evaluation criteria were divided into three groups: concepts, capacity, and plans. Concepts included system qualities of flexibility, efficient use of labor and materials, and schedule forecasting. Capacity involved strength of the built form and the proposer's financial profile. Plans looked at the goals for marketing and production. Of the 22 accepted proposals, ten were volumetric, nine were panel systems, and three were component-based. The primary materials of the systems were similarly varied: six were concrete, one metal, eight wood, two plastic, and five were of a composite material. Table 2-1 gives a brief overview of the 22 systems selected (Wilkes, 1988a, p.13).
Because of the unconventional nature of these experimental systems, new methods of evaluation were
Table 2-1. Operation Breakthrough Systems
Alcoa Construction Systems, Inc.
Building Systems International, Inc.
Christiana Western Structures, Inc.
Descon / Concordia Systems, Ltd.
General Electric Company
Hereoform Marketing, Inc.
Home Building Corporation
Levitt Building Systems, Inc.
Service modules, wood or aluminum framed panels
Steel framed module
Large concrete panels, concreted joints
Large concrete panels, concreted joints
Wood framed panels, service modules
Large concrete panels, dry joint, service modules
Large concrete panels and
cast in place service modules
Lightweight wood-framed modules
Lightweight wood-framed modules
Lightweight wood framed modules
Lightweight wood-framed modules
PRINCIPLE INNOVATION Subsystem wet-core service
Design variability of modules
Materials and techniques
Panel Service assembly, and erection techniques
Factory built framing, sub-assemblies
Element and assembly procedure -uses existing facilities
Panel and service assembly
Cast plaster walls, central utilities chase
Tilt-up and horizontal module arrangement
Medium price range
Less than conventional
Same as conventional
Comparable to conventional
Medium price range
Factory built modules with stress $14/sq.ft.
skin floor panels and roof beam
Factory built modules, hinged roofs
Comparable to conventional
Table 2-1 (continued). Operation Breakthrough Systems
Material Systems Corporation
National Homes Corporation
Republic Steel Corporation
Shelly Systems Incorporated
Stirling Homex Corporation
TRW Systems Group
Inorganic composite panels
Light weight wood- or steel-framed modules
Foam plastic core framed stress skin panels
Foam plastic core framed stress skin modules
Steel faced foam and honeycomb core panels, service modules
Large concrete panels, concreted joints
Lightweight wood-framed modules
Lightweight concrete modules
Steel framed modules assembled by jacking
Precast concrete mega structure, lightweight steel framed panels and modules
Inorganic composite panels or modules
Man-made plastic structural panel material
Factory built panel or module assemblies
Owner erectable system concept
Panel, service module assembly
Factory built modules, conventional appearance
Box module stacking arrangement
Low to medium price range
Less than conventional
Comparable to conventional
$20-25K per unit
6% less than conventional
Medium price range
Created 'land-in-air' concept Not known
Man-made plastic material
More than conventional
necessary to establish conformance with standards for adequate housing. HUD commissioned the National Bureau of Standards (NBS) to provide this criteria, which it provided in the "Guide Criteria for the Evaluation of Operation Breakthrough Systems." This document proved useful beyond the program itself for the revision of codes and standards across the nation to allow for the inspection of unit building systems. The program itself was ran until January 1973, when the Nixon Administration imposed a moratorium on housing funds. Because of the cancellation of the program, the third phase of volume production was seriously affected. At the time, the program was largely viewed as a failure because it never achieved the production goals originally set out. It was also not able to develop the market demand by way of government incentives that it had hoped for. In retrospect, however, the program is seen to have been a major catalyst for change in the building industry, and its failure largely due to its unrealistic goals for the speed of change.
Archiqram and High Tech Architecture
By the end of the 1950's, the architecture of the machine aesthetic derived from the original conception of Le Corbusier, Gropius and others during the twenties and thirties, had become largely stale and banal. In response, a group of disenchanted young architects from London formed a loose association in 1961 and published a series of "manifestoes" called Archigram (an 'architectural telegram').
The original group included Peter Cook, David Greene, and Michael Webb, and they were later joined by Warren Chalk, Ron Herron, and Dennis Crompton. Like Le Corbusier with his Vers Une Architecture before them, their goal was to redefine the values and syntax of modern architecture, based on 'the spirit of the age1. Their age was the space age, and the technology and imagery of Cape Kennedy and the space program was a major source of inspiration for their work. Another inspiration came from an embrace of the values of popular culture, including consumerism, planned obsolescence, and the importance given to public imagery.
The work of Archigram (the people) throughout the 1960's was primarily drawings and exhibitions. The Walking City
(Ron Herron, 1964) was directly inspired by the huge moving structures of Cape Kennedy. Herron's imaginative imagery showed huge insect-like bodies of steel, walking on telescopic legs. Capsule Homes (Warren Chalk, 1964), Gasket Homes (Ron Herron, Warren Chalk, 1965), and Living Pods
(David Green, 1965) explored the ideas prefabricated dwellings that could be stacked into towers or megastructures
(Wilkes, 1988b, p.256). Similarly, Peter Cook's Plug-In City
(1964-66) inserted throw-away units into a concrete megastructure by way of a cranes operating from a railway at the structure's peak. From 1966 onwards, the work of Archigram altogether abandoned traditional notions of architecture, producing projects such as "suits that are homes", the Instant City, and other hybrids of machine,
biology, electronics, and architecture. The Archigram "newsletter" was ceased in 1970, but it was only then that its influence began to be seen in built form. Arata Isozaki further developed the ideas of the Instant City in his section of the 1970 Osaka World's Fair. In that same year, Richard Rogers entered into a partnership with Renzo Piano, and in 1971 they won the international competition for what became the Centre Pompidou in Paris (Figure 2-25). In this building is the perhaps the clearest expression of the architectural style called High Tech.
Figure 2-25. Centre Pompidou, Paris, by Rogers and Renzo, 1977 (Curtis, 1983 p.375).
The importance of Archigram was that it offered alternative ways of looking for solutions to architectural problems. Their movement, described as architectural counter-culture, was perhaps actually more of a "hyper-culture" Many of their ideals were simply updates to or reinterpretations of the original machine aesthetic: engineering rather than architectural inspiration, modularity, industrialized production, adaptability, etc. Their work is definitely true to the spirit of its time, but from an ecological point of view, that is its greatest fault. Referring to the idea of expendable construction, Peter Cook states in Archigram 3, "We must recognize this as a healthy and altogether positive sign. It is the product of a sophisticated consumer society, rather than a stagnant (and in the end, declining) society" (Cook, 1972, p.16). In Modern Movements in Architecture, Charles Jenks states (p.298), "The great contribution of the British avant-garde has been to open up and develop new attitudes towards living in an advanced industrial civilization where only stereotyped rejection had existed before, to dramatizing consumer choice and communicating the pleasure inherent in manipulating sophisticated technology." Yet it is precisely these cultural norms of consumerism and the unbridled glorification of technology that have exasperated many environmental problems. These are values that contemporary environmentalism seeks to dethrone.
As stated earlier, Archigram was a key influence on the High Tech style of architecture. Richard Rogers, Nicholas Grimshaw, and Michael Hopkins three of the four major leaders of the movement were all students of the Architectural Association in the early 1960's. Norman Foster, the fourth major leader of High Tech, studied at the Liverpool school of architecture, but met Rogers briefly at Yale in 1962, and then joined him to form Team 4 upon returning to England. These four have alternately been competitors and associates with each another in the years to follow. Beyond Archigram, however, High Tech has been influenced by such architects as Allison and Peter Smithson, James Stirling, Paul Rudolph, and even Louis Kahn. The hallmarks of High Tech imagery include: exposed steel structure, visible air-conditioning and other services, plug-in service pods, suspension structures. Its ideals are similar to those of past industrialized building philosophies: mass production, flexibility, modularity. It even takes the flexibility idea a step further in proposing that not only should internal partitions be demountable, but also external walls, roofs, and even structural frames. Similarly, it has carried forward the modernist theory of the "honest expression" of materials and means, although (as before) this theory and the actual implementation are often inconsistent.
In addition to the Centre Pompidou, Foster's Hongkong Bank Headquarters and Rogers' Lloyd's of London, both
completed in 1986, are considered major masterpieces of the genre. In Roger's Lloyd's building, the essence of the design is the separation of the service towers containing cables, ducts and staircases from the central atrium. Every element, both structural and mechanical, is expressed on the facade. In Foster's Hongkong Bank the structure is both prominent and unique. Floors are suspended from structures called "coat hangers", which are in turn supported by eight massive masts.
Industrialized Housing Today
Industrialized construction is broadly defined as the off-site production of building components or complete units in a factory setting, which are then assembled or erected on-site. The primary distinction between industrialized construction and conventional construction is the degree of off-site fabrication. In the past few decades, elements of industrialized construction have been absorbed within conventional construction techniques to the point that the boundary between conventional and industrialized construction is fuzzy at best.
Prefabricated components such as manufactured windows, doors, and cabinetry are practically standard in today's 'conventional' housing. Industrialized construction is applied to many different building types: residential,
commercial, institutional, recreational, and industrial. The emphasis of this thesis is upon residential applications.
A variety of terminology is used in describing industrialized building systems. Many of these terms have closely related meanings, and often they are used interchangeably. Unfortunately in doing so, the subtle differences in meaning are sometimes obscured. Other terms that are generally synonymous with industrialized housing include manufactured, factory-built, and prefabricated housing. The term manufactured housing is often used as a euphemism for the more specifically understood term 'mobile home'.
Building systems is another term commonly used in the realm of industrialized construction. A system can be defined as a kit of parts designed to be combined into a unified whole to accomplish a desired objective. It is this definition, with the emphasis on 'combined into a unified whole', which provides the important concept of holistic design that has often been ignored in the concept of industrialization. A systematic design philosophy includes the idea that the interrelationships between the parts are as important as the parts themselves, and it is in this context that the environmental implications of building are most clearly understood.
Building systems are classified as open or closed. An open system allows interchangeability of its own components with another system's or producer's, while components of a
closed system are only interchangeable internally. The term building systems is sometimes used in another sense, where products are referred to as hardware or software. Hardware refers to actual physical products; software which refers to a procedure or program for producing and marketing building products.
There are many different variations on the basic concept of an industrialized building system. Systems are often grouped together into categories to help understand commonalties and differences. Different authors propose different groupings, but the constituent systems that are recognized are generally the same. In regards to the U.S. housing market, the U.S. Department of Energy's Office of Building Technologies recognizes four types: HUD Code (mobile homes), modular houses, panelized houses, and production-built housing.
HUD Code is the official name of the category commonly refer to as mobile homes. They are constructed for year-round living, outfitted with wheels, and towed to the site where they are connected to a foundation and utilities. The term mobile home is primarily a historical vestige referring to their evolutionary ancestor, the trailer home. Today's mobile homes are built around economy rather than mobility as the primary objective; they are today's low income housing. Even though many still retain the trailer chassis, most are
never moved once they have been delivered to their initial site. (The wheels are typically removed and sold after their initial use.) The term HUD Code refers to the fact that today's mobile homes are constructed according to building codes administered by the U.S. Department of Housing and Urban Development, which supersede local and state building codes for these homes. Mobile homes also have special tax rates (licensed as motor vehicles and not taxed as real estate) and financing which further enhance their economical status. On the other hand, mobile homes neighborhoods are often considered as less desirable and are often subject to housing restrictions.
Modular homes (also called sectional homes) are built by stacking together two or more three-dimensional house sub-units. Each sub-unit contains one or more rooms; they are factory assembled, shipped to the site, and then stacked together, often using a crane. Modular homes are set over a standard foundation and financed in the same way as conventional houses. Moshe Safdie's Habitat housing complex in Montreal is an example of modular housing made from precast concrete technology. Many of today's modular homes have evolved from the 'single-wide' mobile home to double-wide and triple-units. It is mainly their separation from the trailer that technically qualify these modular homes as permanent housing, and circumvent the associated restrictions placed on mobile homes.
Panelized houses are constructed from manufactured roof, floor, and wall panels on site. Whereas the building block of a modular home is a three-dimensional unit, with the panelized home it is two-dimensional panel. Panelized wall units are either open wall, with one side open for inspection by local building officials, or closed wall. Closed wall units include wiring, plumbing, and insulation built-in and must be inspected at the factory. Open wall units may or may not include these utilities.
The fourth type, production-built housing, "refers to the mass production of whole houses, either in a factory as completely assembled units or at the site, which becomes an open-air assembly line where labor and materials are processed by advanced manufacturing methods into finished houses" (DOE 1). The on-site fabrication with this type is an exception to the general definition of industrialized construction given previously, but it includes the idea of mass production techniques. Tract housing is an example.
In addition to these housing categories, there are others which are often discussed in the industry literature. One of these is the precut house. Precut houses are units that come from the manufacturer as a package of precut lumber components. Log homes, A-frames, and geodesic domes are examples of precut packages, although they are many times considered as separate categories. Precut home kits may or may not include items such as plumbing, heating, and wiring kits. Wet cores or service modules are "special modular
components for housing that contain all the electrical control and mechanical and plumbing services required for a single housing unit" (Sullivan, 1980, p.72). Self-contained bathroom or kitchen modules are common examples. These service modules are often used in conjunction with other systems. In addition to modular and panelized (which essentially mean three-dimensional and two-dimensional) systems, there are skeleton or frame-based (one-dimensional) systems, also sometimes referred to as component systems. Stick-built (also called platform construction, or custom) housing is technically a frame-based housing system, although it is generally not considered industrialized construction since most fabrication takes place at the site. Metal building systems are another category of industrialized building which are often frame-based systems. All-metal systems are more prevalent in industrial and utilitarian applications than in residential housing, although this is slowly changing.
Comparisons Between Categories
The different types and categories of manufactured housing have different strengths and weaknesses. Consider the categories of mobile, modular, panelized, and component housing. As described earlier they can be considered as points on the "dimensionality scale": mobile homes are whole units, while modular, panelized and component systems represent sub-units of three, two, and one dimension. For
comparison purposes, they can also be considered as points on a spectrum of the degree of factory versus on-site fabrication. At one end is the mobile home, completely factory built, requiring only to be hooked up to utilities and "strapped down" to foundation anchors once transported to its site. At the component end, many different components and subsystems are assembled on site. In general terms, the mobile home end of the spectrum maximizes economy while sacrificing design flexibility, while the component end of the spectrum inverts this relationship.
Sullivan (pp.224-25) offers this list of advantages and disadvantages for the major housing types:
- extremely low costs relative to other housing types
- a wide range of mobile home units of different style, size and features
- low taxes and relatively low maintenance costs (mobile homes must be licensed as are motor vehicles)
- mobile homes can ,if desired, be easily relocated
- units may be shipped long distances from manufacturer or distribution centers (from 500 to 700 miles)
- relatively low transportation costs
- mobile homes are essentially a form of instant housing
- financing is relatively easy to obtain
- space rental and upkeep is relatively inexpensive (mobile homes are not taxed as real estate)
- prejudicial zoning keeps mobile home parks from good quality neighborhoods
- many existing parks are of low quality, offering few amenities
- mobile homes depreciate over time
- long term financing is not available (12 to 15 years maximum)
- mobile homes have a shorter life span than other forms of housing
- transport requirements impose limitations on unit design and layout
- modular housing is generally subject to real estate tax and as such qualifies for long-term financing in the form of the traditional mortgage
- the modular home, in general, will appreciate with time, as in the case of traditional housing
- modular housing has a reputation for superior quality relative to most mobile housing and, hence, experiences greater consumer acceptance
- there is a wider variety of forms of modular housing than mobile homes
- there are fewer problems with code acceptance
- there is more flexibility in design
- modular housing has greater structural stability than mobile homes when placed on conventional foundations
- the modular home is generally more expensive than the mobile home
- lower volume production from most modular housing producers prohibits the advantages of volume production
- modular housing requires more preliminary site work and installation than mobile housing
- the transport limitations that apply to mobile homes also apply to modular housing
- greater flexibility in design than either modulars or mobiles
- greater ease of shipping since components can be tightly packed
- because of the superior transport situation, the market range can be considerably larger
- the buyer or consumer can be involved in the design process, determining the unit layout to suit his or her preferences
- the buyer has the option of reducing costs by handling a part of the assembly or of finishing the unit himself
- the unit can be more easily designed and manufactured in compliance with codes
- far less problems with prejudicial zoning that limits the places where such housing can be erected
- lack of quality control due to the amount of work that must be carried out at the site
- generally higher costs than either mobile or modular housing, due to the amount of site labor required
- owner must assume responsibility for arranging the general contracting or perform the function himself
- there is considerably more time involved in the construction than with either mobile or modular housing
- there is a problem with storage when all the materials and components for the housing unit arrive at the site at once, and the unit might take from one to four weeks before it is enclosed
- there is less need for skilled labor at the site
- skilled labor employed at the factory, where higher volumes of production per worker is possible
- industrialization is applied to the high cost items of housing
- there are no problems with storage if the unit is delivered to the site when everything is ready for installation
- it can be used in both traditional and industrialized housing
- there is better quality control of high cost labor operations
There are some additional disadvantages to mobile housing not explicitly listed by Sullivan, including poor quality construction, poor energy performance, and the inability to be site specific.
EMERGY ANALYSIS OF VARIOUS CONSTRUCTION MATERIALS
This chapter deals with the energetic costs associated with the production of commonly used construction materials. The analysis is based on eMergy theory, developed by Howard Odum. This analysis is equivalent in purpose to the concept of "embodied energy"; however, the methodology involved in the analysis is different in a number of ways. The key differences include the scale of the analysis and the concept of energy qualities, called transformities.
Consider the difference between coal and electricity. In embodied energy analysis, typically no distinction is made between different types of energy; all of the required Joules of energy of different types in a process are added together to determine the total. Yet it takes about four Joules of coal to produce one Joule of electricity. A Joule of electricity must be of higher quality (i.e., it has greater utility for some further process) than a Joule of coal; otherwise, it would never have been produced in the first place. Thus, to accurately measure the total energetic costs associated with a given process, the concept of energy qualities (transformities, sej/J, or eMergy per unit mass
sej/g) must be considered. In certain cases, this difference in quality is recognized by conventional energy analysts; the transformity between fossil fuels and electricity described above is sometimes factored into embodied energy calculations. Only eMergy analysis, however, incorporates the concept of energy qualities in a fundamental and systematic manner.
The issue of scale of analysis is related to the understanding of energy quality. Because different types of energy have different transformities, it is necessary to establish a baseline; in eMergy analysis, that baseline is solar energy. Thus the units of transformity are solar emjoules per Joule (sej/J), and the units of eMergy per unit mass are solar emjoules per gram (sej/g).
The eMergy content of a number of construction materials were evaluated, including wood, steel, concrete, and glass products. For each eMergy analysis, a primary source of data that contained as much of the necessary raw information as possible was used. Any missing raw data was generally available by including one more source, and care was taken to put this data on a common basis with the primary source. The object of this approach was to minimize potential errors introduced by multiple data sources with inconsistent assumptions.
For each material or product evaluated, transformities were calculated both with and without human services. Human services were considered as everything associated with money, including labor, dollars paid for materials and fuels, and profits. Human services were always evaluated as a single comprehensive dollar amount represented by a product's selling price; material and fuel inputs were evaluated solely on the basis of their "natural" eMergy content. By keeping track of human services separately, a consistent method is established to prevent the double counting of human services.
The first category of materials analyzed were wood products, with the primary data source being the 1976 study by the Committee on Renewable Resources for Industrial Materials (CORRIM) Panel II. As a secondary source, the US Census of Manufacturers was used to provide comprehensive data on human services. The CORRIM data was generally taken from the year 1970, while the Census data was from 1972, but adjusted to a per-unit basis and applied to 1970 quantities.
Three hierarchical levels of wood products were evaluated. First, an analysis of timber harvesting for the entire United States produced a transformity for cut logs. This value fed the analysis of the second level, primary wood products (including lumber and plywood, both softwood and hardwood). Primary wood product manufacture generates a good deal of wood by-products, including chips, sawdust, bark,
shavings and trim. The sawdust and bark can be burned to produce a large percentage of the energy needed for the products' manufacture, although it is not clear to what extent this resource is actually utilized for this purpose. Therefore, eMergy analyses were done in two ways for primary wood products; one assuming all available sawdust and bark was recycled as fuel and secondary wood product materials, and the other assuming no such recycling.
The third level of materials evaluated were secondary wood products those made largely with by-products generated from primary wood product manufacture. This includes particleboard, fiberboard, insulation board, and hardboard. Obviously, the transformity of wood by-products from the second evaluation level fed these calculations. Interestingly, the average transformity for wood by-products from all primary lumber production processes was essentially the same for both recycling and no-recycling assumptions.
Figure 3-1 illustrates the eMergy flows for logging production in the United States as a whole for the year 1970. Table A-l in Appendix A lists the data and analysis corresponding to this figure. It should be noted that because rain and sunlight are both driven by the same energy source (the sun), only the larger of the two is included in the outflow total. Thus, the total eMergy outflow (1574.1 E20 sej/yr) is the sum of the inputs rain (816.0 E20 sej/yr),
Figure 3-1. US Roundwood Production, 1970.
Primary Wood Products
Primary wood products including softwood lumber, hardwood lumber, softwood plywood, and hardwood plywood were analyzed. Figures 3-2 through 3-5 illustrate the eMergy flows associated with each on a annual basis for the year 1970. Tables A-2 through A-5 lists the data and analyses corresponding to these figures.
fuel (79.4 E 20 sej/yr) and human services and labor (678.7 E 20 sej/yr).
Softwood Lumber Production, 1970
With Sawdust Recycling
Figure 3-2. EMergy Flows for US Softwood Lumber Production, 1970.
Hardwood Lumber Production, 1970
Without Sawdust Recycling
[ Services/ V Labor J Emergy Flows, E12sej/ton
1 481 \ Hardwood Lumber
463 Hardwood Lumber Manufacture 944 / / Sawdust, Bark
< S^^Shavings, Trim ^vi/Vood Chips
Hardwood Lumber Production, 1970 -J r With Sawdust Recycling
Figure 3-3. EMergy Flows for US Hardwood Lumber Production, 1970.
Emergy Flows, E12 sej/ton
Softwood Plywood Manufacture
Softwood Plywood Production, 1970
Without Sawdust Recycling
Emergy Flows, E12 sejVton
Softwood Plywood Manufacture
Softwood Plywood Production, 1970 -X
With Sawdust Recycling
Figure 3-4. EMergy Flows for US Softwood Plywood Production, 1970.
Hardwood Plywood Production, 1970 JL
With Sawdust Recycling
Figure 3-5. EMergy Flows for US Hardwood Plywood Production, 1970.
Secondary Wood Products
Secondary wood products including particleboard, fiberboard, insulation board, and hardboard were analyzed. Figures 3-6 through 3-9 illustrate the eMergy flows associated with each on a annual basis for the year 1970. Tables A-6 through A-9 lists the data and analyses corresponding to these figures.
[ Steam \ t Natural ] ( Electrical ] [ Services,]
V Energy J V Gas J\ Energy J V Labor J
\ 188 I 138 I 166 I 430
Particleboard Production, 1970
Without Sawdust Recycling
Emergy Flows, E12 sej/ton
Figure 3-6. EMergy Flows for US Particleboard Production, 1970.
Figure 3-7. EMergy Flows for US Fiberboard Production, 1970.
Figure 3-8. EMergy Flows for US Insulation Board Production, 1970.
Figure 3-9. EMergy Flows for US Hardboard Production, 1970.
Three types of steel products were evaluated: raw steel (in molten form, without human services only), finished mill steel products in general, and fabricated structural steel products. The primary data source for the raw and mill steel evaluations was the American Iron and Steel Institute's (AISI) Annual Statistical Report. Analyses for these materials were made for the years 1972 and 1991, showing a significant increase in production efficiency (and decrease in quantity) for the US steel industry over this period of time. In addition, an analysis for fabricated structural
steel products.was done for the year 1972 based on the data provided by the US Census of Manufacturers.
A significant source of the raw material for steel production comes from recycled scrap iron and steel. In eMergy analysis, materials or energy which are part of a process feedback are not added into the summation of costs, to avoid double counting of that resource. The only additional costs associated with this input is that associated with the additional human services, fuel, etc. required to recycle it. The "natural" cost has already been accounted for in its original production. Figures 3-10 through 3-12 illustrate the eMergy flows associated with each analysis, based on total annual inputs and outputs for the years specified. Tables A-10 through A-12 lists the data and analyses corresponding to these figures.