Citation: Spray-On House

Polyurethane spray foam is known for its use as insulation, quickly and effectively filling in wall cavities and lining attic roofs. The Spray-On House by Patrick Tighe Architecture shows how it can do much more.

After years of researching the high-density spray foam’s structural capability, the firm is embarking on its first building using the material. The single-family house in the quirky and remote desert community of Pioneertown, Calif., will be a curvaceous, gourd-like mound with globular interior spaces and hardly a straight line to be found. The spray foam, installed in one continuous application, in combination with a cage of steel reinforcing bars, will become the house’s foundation, walls, and roof.

Polyurethane is an ideal construction material for the remote site, where access would be all but impossible for multiple trades and their equipment. Requiring minimal materials and labor, the house is expected to cost just $125 per square foot. And by using soy-based foams, the environmental impact of building the Spray-On House will be significantly less than a comparable house built in concrete. A life-cycle assessment of the prototype house found that it would require less than half of the fossil fuels consumed in concrete construction and produce about 10 percent of the harmful respiratory inorganic compounds.

The firm’s past research into spray foam culminated in a 2011 temporary installation (shown at left) at the Southern California Institute of Architecture that used a combination of high- and low-density foams to build a free-standing, parabolic chamber. “We were looking at the thinnest shell we could get, using the highest density foam,” says firm principal and lead designer Patrick Tighe, FAIA. The prototype shell was 3 inches thick, stood 20 feet tall, and covered 600 square feet.

The 2,700-square-foot Spray-On House will require greater foam thicknesses, ranging from a few inches at the roof to a few feet at the wall base. The project’s engineers have tweaked details like the location and size of interior walls to ensure the structure can support itself. In addition, the team has built full-scale prototypes of wall sections and footings to optimize the quantity and thickness of the foam.

The firm is still determining how best to coat and waterproof the house exterior. Still, Tighe says, the biggest challenge has been navigating the project through the building code.

Bureaucracy aside, the jury saw great potential in this exploration of foam-based design and construction. “It seems unlimited in what you can do with the process,” juror Elizabeth Whittaker, AIA, said.

See all the 2016 R+D Award winners here.