The Arc House: A Resilient Prototype
From urban-infill residence to off-the-grid retreat, The Arc House is at home anywhere.
JIM GREGORY, FOUNDER of Shelter Dynamics, likes to call The Arc House a “demonstration of a direction” in housing. Its small footprint, independence from the grid and versatile design make it an ideal solution for urban, suburban and rural settings. The Arc House can serve as a primary residence for a single person or a couple, or it can be used as a retreat, vacation home or “mother-in-law” unit. Clusters of Arc Houses can create small communities, based on the cooperative housing model, in which each household enjoys private space but also shares common areas such as courtyards and gardens.
Fiber cement siding is extremely durable, fireproof, and resistant to insects and Mother Nature.
The Factory Advantage
The Arc House is factory built and transportable, giving it flexibility in its ultimate destination. Gregory envisions his product as a solution for West Coast states first.
“Shipping and logistics pretty much dictate that we stay west of the Rockies and south of Seattle,” says Gregory. “However, we are looking at the potential for kits or partnerships that might help meet the demand in other areas.”
Shipping requires a special permit and—depending on the jurisdiction—at least one pilot car, sometimes two. The buildings are set with a crane, which can drive up the cost if the site is remote.
Regardless of its destination, each Arc House must be built according to approved plans and meet the standards of the California Factory Built Housing Code. For his first prototype, Gregory made the curved beams that form the skeleton of the structure himself, using 3/8-inch strips of structurally rated Douglas fir glued together with marine epoxy. These “epoxy-lams” were so strong, they exceeded the testing machine’s capacity. Now he is having glu-lams made by a third party, but they—and the structure—are still exceptionally strong.
Gregory plans to build Arc Houses in a “tent factory” near his home in Ridgefield, Calif. Each unit is inspected in the factory by a third-party inspection agency—in this case, RADCO Plan Review and Inspection Services. In addition, Gregory developed and must maintain a quality control program to ensure the process is replicated with each new unit. The dwellings must also meet the standards of local jurisdictions for snow and wind loading, fire resistance, setbacks and other criteria.
Building in the factory provides more control over the process, allows for specialized teams of workers and produces less waste. Gregory estimates that building in the factory can reduce to zero the eight pounds per square foot of material that is usually wasted in site-built construction. And for Gregory, this is as important as the finished product.
Fire, Wind and Rain
The construction and durability of The Arc House also gives it an edge. Exterior materials were chosen carefully to ensure resistance to fire, wind and extreme weather. A combination of Bayseal spray foam and Bayblock acrylic roof coating from Covestro protect the curved portions of the structure from moisture, UV degradation and temperature fluctuations. The straight side and ends of The Arc House are clad with Allura fiber cement siding over DuPont Tyvek house wrap. Fiber cement siding is extremely durable, fireproof and resistant to insects. When used in combination with a weather-resistive barrier, this system also offers superior moisture protection.
Inside, a fire sprinkler system protects The Arc House. In California, home fire sprinklers are required in all new factory-built homes, and in one- and two-family site-built homes and townhomes. According to the National Fire Protection Association (NFPA), home fire sprinklers save lives and property. Automatic fire sprinkler systems cut the risk of dying by about 80 percent and reduce the average property loss by about 70 percent.
In The Arc House, fire sprinklers will protect not only the occupants, but also the high-quality interior casework, flooring, appliances and finishes. The dwelling was built for longevity, inside and out.
After all, says Gregory, “Sustainability starts with building something that lasts for a long time.”