As the U.S. Green Building Council puts the finishing touches on its new residential certification program, another housing trend is already making inroads on the residential building market: modular construction. Attracted by the resource- and cost-efficiencies associated with building houses in a controlled factory setting, a growing number of architects and builders are designing compact, environmentally improved modular dwellings, which are either delivered to the site complete or in flat-packed housing kits.
These aren’t your father’s fake Tudors or trailer park homes. On the contrary, contemporary prefabrication is steeped in a sleek, modernist and “green” aesthetic. Consider the 1,500-square-foot Glidehouse by San Francisco architect Michelle Kaufmann, who worked for Frank Gehry before debuting her wood, steel and glass structure which incorporates daylighting, bamboo flooring, and recycled materials. Or consider 34-year-old Missouri architect Rocio Romero’s LV house: a stylish, light-filled 1,150-square-foot dwelling that comes in panels of corrugated aluminum and costs an estimated $29,000.
Once the lowly stepchild of the architecture industry, prefabricated housing is now “hip and happening,” said Rob Bennett, director of the green building program at the Portland Office of Sustainable Development. Modular housing encourages mass production of environmentally superior technology, Bennett said, and it mainstreams green building for people who might otherwise find it too expensive. “You get a better market transformation,” said Bennett, who in August begins a job with the City of Vancouver, B.C.’s new sustainability office.
Prefabrication reduces construction waste, encourages regional adaptations of the building envelope and reduces the cost of green building materials, said Sandy Hirshen, architect with Vancouver B.C.-based Henriquez Partners and retired director of the University of British Columbia School of Architecture.
An advocate of low-cost prefabricated housing since the 1960s, Hirshen designed a modular “Flexible Hybrid” home that won a 2003 competition for affordable green housing. The competition was sponsored by the Southeastern Center for Contemporary Art in Winston-Salem, N.C. “Prefabrication is not a panacea for everything,” Hirshen said. “But it can contribute to sustainability.”
Great Green North
Over the past few years, British Columbia has emerged as a hotbed for modular activity, from design to manufacturing. A Surrey, B.C.-based company, Britco Factory Built Buildings, recently opened offices in Portland and Seattle, as well as a second manufacturing facility in Penticton, B.C. “Our business is more than twice what we did last year,” said Tom Faliszewski, Britco’s housing division manager. Over 40 percent of the company’s business is now in residential, he said. “It’s the fastest-growing area of our company.”
Britco uses certified flooring and cabinetry, as well as paints with low toxicity, Faliszewski said. The company also offers energy-efficient and renewable energy options such as photovoltaic cells that produce on-site solar energy, he said. Britco manufactured Hirshen’s Flexible Hybrid home using mostly environmentally certified products, said Hirshen. “With prefabrication, you have the power to purchase at a scale that makes sense,” he said.
Kaufmann’s Glidehouse, which is also manufactured by Britco, became a national sensation after it was featured in Sunset magazine in 2004. Kaufmann said she witnessed “first hand just how green modular can be” after seeing her Glidehouse built both on-site and in a factory using modular technology.
Despite using a reputable green builder, the on-site Glidehouse still generated an enormous amount of construction waste, Kaufmann said. “The factory, however, minimized waste,” she said. “They use computer-precision cutting, they have storage capacity, and they have repetition.”
Alistair Jackson, a project associate at O’Brien & Co., a Bainbridge Island, Wash., green building consultancy, said a controlled construction environment is the perfect place to incubate a green building workforce.
“A home has become a highly engineered thing,” said Jackson, adding that an on-site contractor usually works with a variety of subcontractors who may or may not have the requisite technical training. “But a dedicated manufacturing facility can develop the workforce to deliver the required level of air sealing we’re now expecting from energy-efficient homes. The fewer holes there are in a house, the more important those holes become.”
Kaufmann cited other advantages of prefabrication. Mold and moisture are reduced when the framing isn’t exposed to elements, she said. And if the modular costs of construction are reduced, clients and developers can apply savings to alternative energy sources such as solar panels or geothermal systems.
While the typical American residence has ballooned to more than 2,500 square feet, modular designs have another advantage: a smaller physical and ecological footprint. After all, most prefabricated dwellings aren’t much bigger than a 16-by-45-foot box — a measurement designed so the homes can be transported on roads.
Vancouver B.C. architects Todd MacAllen and Stephanie Forsythe have designed a 675-squarefoot prefab called Maison Mini, as well as a modular interior design called “soft housing,” wherein residents can partition small spaces with accordion-like walls made out of paper, wood and felt. The duo is currently incorporating soft housing in their award-winning design of a former New York flophouse.
“The sense of sustainability comes in the use of flexible, adaptable space,” said MacAllen, who until recently lived and worked with Forsythe in a 700-square-foot space in downtown Vancouver. “Rather than have separate rooms for separate functions, you can partition space to make it private, then collapse it to regain an open plan. So you can actually use a smaller footprint for the house.”
At home in a cargo container
Seattle architects Robert Humble and Joel Egan have taken the idea of temporal modular space one step further. Last year, the two founded Team HyBrid, a collective of architects and artists providing what they call “cargotecture” — prefabricated housing, which recasts 40-foot cargo containers as building modules. Humble said cargotecture’s nomadic sensibility is a perfect fit for languishing parcels of land in downtown Seattle. Their idea is to deploy the cargo containers as affordable housing until the land is ready for a developer to build a more permanent structure.
“After 50 years, most buildings have expended their useful life,” Humble said. “What we envision is that at the end of 50 years, the building can actually be removed when conditions are economically viable.”
Team HyBrid designs insulated, glazed boxes inside the cargo container. The “box-within-a-box” has glass and panelized insulation for the walls and foam block for the floor. When the cargo container is disassembled, the interior box is removed and the steel container can be either reused or recycled.
Cargotecture was on display during the American Institute of Architecture’s 2004 exhibit in Seattle. Humble said several affordable housing projects using the containers are in the design phase.
Critics of initiatives such as U.S. Green Building Council’s LEED (Leadership in Energy and Environmental Design) rating system often focus on programmatic costs and the bias toward high-end projects. Although modular housing levels the playing field, some architects warn that the inherent mobility associated with modular housing also makes it an attractive option for wealthy homebuyers seeking second homes in coastal or mountain areas. MacAllan conceded his initial idea was to promote modular cottage design for the vacation set.
“That kind of died,” he said. “Now we’re interested in small buildings, density and cities, where you get more for less money and make less of an impact.”