Ron Herron/Archigram Exhibition Poster, Institute for Architecture and Urban Studies, 1978, courtesy of Tim Culvahouse.From fasteners to fantasy cities, prefabrication has long nurtured both the practical and the theoretical. Some notions about prefabrication readily enter the construction lexicon; others remain forever cast as brilliant yet unrealizable dreams. What they share is resistance to a fragmented design and construction industry characterized by ossified disciplinary and classificatory lines. As with other project delivery methodologies, such as design-build and integrated services, prefabrication seeks to blur or erase such lines by re-asserting the fundamentally collaborative nature of architectural production. In doing so, it tackles a host of socio-economic, environmental, and aesthetic objectives at multiple scales of application.
By its narrowest definition, prefabrication privileges shop over field labor. From this perspective, almost any factory-produced material, component, or system intended to reduce or improve upon field labor may be seen as prefabricated. The lowly nail, cut on-site by craftsmen from iron bar until nail cutting machines made this labor-intensive technique obsolete in the 19th century, is but one example.
Similarly, pre-cast concrete wall, stair, and structural components offer efficiencies often exceeding that of traditional in-situ construction methodologies, most notably in high-rise construction, where restricted site access and strong economic pressures drive ever-increasing reliance on off-site fabrication and quality control. Indianapolis-based National Precast Concrete Association, for instance, sponsors a factory certification program in which both the final manufactured product and its constituent materials undergo regular inspections. Indeed, from awnings to z-moldings, the term “prefabricated” has emerged as a market-savvy term evoking cost, time, and quality benefits for a host of building products.
By its broader definition, however—and this is where the blurring of disciplinary and trade boundaries comes into play—prefabrication entails the assemblage of interdependent materials and components in a controlled production environment as an alternative to traditional on-site construction by a collection of unaffiliated, specialized trades. The pre-hung door assembly, ubiquitous in residential and commercial construction, is a simple example. A door selected by the architect or builder is mortised in the factory, mounted with a specified hardware package into a wood or metal frame, and delivered to the jobsite for quick installation in to an interior or exterior wall.
The complexity increases somewhat with larger multiple-component assemblies, such as prefabricated walls, a building strategy employed since before the American Civil War, when modular wall panels were available to frontier-bound pioneers who chose not to rely on the availability of local raw materials. In today’s construction market, prefabricated walls—categorized loosely as open sheathed panels, structural sandwich panels, and unsheathed structural panels—are widely available, complete with framing members, glazing units, door assemblies, insulation, weather barrier, and exterior finish.
Beyond this generic assemblage, prefabricated walls may be filled with mechanical, plumbing, and electrical components or, as in the 1950s Case Study House by Rafael Soriano, storage units incorporated into factory-built interior partitions. Manufacturers of prefabricated wall assemblies today employ a variety of promotional arguments, but the common narrative is that factory-built wall assemblies minimize the impact of inclement weather on construction schedules, facilitate continuous and consistent quality control, reduce costly and space-consuming on-site storage requirements, and simplify onsite management of multiple trades.
Quonset Hut Type 1, Barbers Point Naval Air Station, Honolulu County, Hawaii, 1940s, courtesy of Library of Congress.Factory-built wall assemblies lead inevitably, of course, to discussion of prefabricated buildings. As early as the 1820s, British settlers toted portable modular cottages on their journey to inhabit Western Australia. In the modernist era, the distilling of a house to a set of standardized, reproducible, and adaptable components to facilitate rapid and cost-efficient field assembly has a long history of experimentation. In the 1940s, Walter Gropius and Konrad Wachsmann pursued such a dream with their General Panel System kit of parts (see Dora Jones’s article in this issue of arcCA), and the 1950s post-war housing demand fueled wide-ranging research and development activity on prefabricated homes.
Terminology in the contemporary prefabrication industry is a bit fluid, but the discussion tends to revolve around four general classifications of “factory-built” structures. Pre-cut buildings, the first classification, are assembled in the field from a factory-supplied kit of parts—Lindahl Cedar Homes is a well-known example—containing all necessary construction materials and components. Panelized buildings, by contrast, rely more heavily on prefabricated floor, wall, and mechanical assemblies in an effort to reduce the field labor required for construction. The iconic Dymaxion House (1927-28) by Buckminster Fuller, with its central mast housing a prefabricated service core and a kit of parts, might today be viewed as a hybrid of these first two classifications.
The reliance on factory labor is further extended with modular buildings, the third classification, comprised of two or more prefabricated modules delivered to the site for assembly on a site-built foundation, and to its ultimate iteration with manufactured buildings, which are pre-assembled in their entirety before delivery to a site. While the attributes of each classification vary, the most frequently cited advantages over traditional field labor-oriented construction are continuous quality control, reduced weather delays and material damage, assemblers working for the same business entity, and, in the case of mass-produced homes, cost efficiencies gained through the volume purchase of building materials.
Buckminster Fuller, Dymaxion House.It has become increasingly evident that prefabrication—long an object of derision by architects for its seemingly obsessive attention to stripped-down standardization and a presumed absence of stylistic sensibility—is no longer a building strategy limited to the mass production residential market. A case in point is a recent exhibit curated by Andrew Blauvelt for The Walker Art Center in Minneapolis with support from Dwell magazine and furniture retailer Design Within Reach. Entitled “Some Assembly Required: Contemporary Prefabricated Houses,” the motivation behind the exhibit was to draw attention to recent technological advancements in prefabrication and to promote its future potentialities. The exhibited projects—ranging from a ten-module Desert house prototype (2005) by Marrnol Radziner + Associates to the one-room weeHouse in Wisconsin (2003) by Alchemy Architects offered on a turn-key basis with all bur appliances and mechanical equipment—demonstrate an array of approaches to prefab experimentation and a vibrant interest in mainstreaming its technologies within the architectural community.
Further evidence of architectural interest in prefabrication is the recent announcement of a 2007 AIA Education Award to the ecoMOD project at the University of Virginia—directed by architecture professor John Quale and engineering professor Paxton Marshall—with the stated objective of generating ecologically-sensitive, prefabricated prototypes for the affordable housing market
Prefabricated buildings have long served other market sectors as well. Fully functional data centers housed in standard transportable containers facilitate expansion of existing technology infrastructures without the time-consuming design and construction process customarily associated with building expansion or renovation. These mobile data centers include on-board technology configured to a user’s requirements and the HVAC and UPS support systems critical to sustaining proper environmental conditions. While there is some argument in the technology industry as to whether such prefabricated data centers are viable as a long-term solution, it is clear that they can serve as part of a comprehensive disaster recovery effort when a primary technology facility is non-operationaI.
Similarly, prefabricated central operating plants complete with mechanical, electrical, and plumbing components are touted as alternatives to time-consuming central plant construction. Prefabricated steel buildings—think Butler Buildings—have, since early in the twentieth-century, served a broad range of building typologies for agricultural, industrial, commercial, retail and military use.
Butler Storage Building, Clay Spur Bentonite Plant & Camp, Weston County, Wyoming, 1940s[?], courtesy of Library of Congress.
If buildings and bridges can be prefabricated, why not an entire city? One can argue that prefabrication has pervaded much twentieth-century thinking about the city. Amidst a deepening conviction in architecture as a transformative tool, early modernists idealized the Functional City as a rationalized, systematized, and mechanized organism constructed anew to replace its chaotic pre-industrial predecessor. This tabula rasa strategy may be seen in the fantastical 1914 Citta Nuova of Italian Futurist Antonio Sant’Elia, again in the 1925 Voisin Plan by Le Corbusier for a new city within a city, and subsequently manifested most notably in Brasilia at mid-century. In the 1960s, the Walking City and Plug-in City depicted by Archigram similarly suggested abandonment of the existing urban fabric in favor of a prefabricated habitable infrastructure that, through its modularity and mobility, would respond swiftly to evolving societal needs. These were mere idealizations, but they tantalizingly envisioned solutions to the human condition through a paradigm of prefabrication.
Mobility and modularity remain key attributes in contemporary discourse about prefabrication and societal objectives, but the scale tends toward either the more realizable—affordable housing assembled from sustainable prefabricated modules—or the more ephemeral—interim solutions such as the problematic FEMA ‘cities’ deployed in the wake of Hurricane Katrina. Even accommodations for the next generation of explorers, the International Space Station—started in 1998 with a pre fabricated Russian control module and recently expanded with an Italian-made bus-sized ‘room’—evidences an attention to mobility and modularity for an inhabitable infrastructure at a smaller scale of application than that of the unrealized Archigram cities.
While this may seem to suggest an outer limit to the scale of application for prefabrication, its potentialities are indeed limitless. Prefabrication, as we have seen, is more than a building strategy or project delivery methodology. It is a paradigm of design and construction, one that accentuates and capitalizes on the fundamentally collaborative character of architectural production. With such a view, there are no limits to the scale of application.
Author Steven I. Doctors is principal of The CM+ Group, LLC, a project management and consulting practice serving the San Francisco Bay Area. he is an adjunct professor in the Architecture and Community Design program at the University of San Francisco and a Ph.D. candidate in architecture at the University of California, Berkeley.
Originally published 4th quarter 2007 in arcCA 07.4, “preFABiana.”
