a couple of days. Where basic housing is needed, such as after a flood or earthquake, simple models can replace tents and primitive shelters.
With friction joints, nails are eliminated. Since the components are cut with laser accuracy, they can be forced together with a rubber mallet. Glue can be added to strengthen the joint. (The friction joint design that Difra uses is based mainly on expired Swedish patents.) “$600 for materials is all that is needed for a small house,” says Walker.
Additional costs are incurred for surface treatment, piping, electricity, and so forth. But even the design, cutting, and placement of pipes and siding will eventually be automated using CAD and laser cutters, Walker says.
Cox and Walker say Difra’s approach is environmentally friendly, since cutting the engineered wood, called steam board, produces less waste wood compared to ordinary construction methods. Depending on local climate and circumstances the steam board may be prepared with anti-termite or anti-fire agents or other substances for special needs.
Given that Difras’s technology could make building homes cheaper, easier, and greener, there ought to be a market for it—but it’s unclear, so far, how the conservative building industry will react to the idea.
“The reason why prefab homes haven’t caught on in the past is because of unappealing designs,” says Walker. “They have been too boxy and identical. Our houses are not factory built, but rather factory cut—that’s a significant difference. We offer an almost endless variety in designs.”
So far, Difra has designed a number of models, and the first full-size prototype, a 600-square-foot small house, is on the way. It will be built in Boston within the coming weeks, on seaport space donated by the City of Boston.
The firm intends to oversee the manufacturing and construction of the first batch of houses itself. Customers are free to hire their own architects, but Cox and Walker say they can offer design and architectural expertise as well. Difra hopes to staff up with more employees soon, and is in fundraising discussions with real estate firms, software entrepreneurs, and angel investors, according to Cox and Walker.