Pure Metal House, Red Hill, North Carolina
I knew this would be an unusual house when it became clear that our client-architect meetings could not take place indoors due to the severe chemical and mold sensitivities of both clients. When they were first in touch with me, the clients had already done a great deal of research into state-of-the-art healthy homes (for 1998) and had found that none of the recommended strategies would be adequate to keep them healthy.
For the first six months, our meetings, emails, and phone calls were directed toward the search for an appropriate building system. Every proposed component was scrutinized for both its impact on building physics and on health. All building materials were personally tested by each client by placing the material in a sealed plastic bag for 24 hours, then breathing air from the bag. After fleshing out preliminary details for a building system, we decided it would be best to build a small guest house to make sure our solution would work.
A year later, after much trial and tribulation, my clients moved from their 80-square-foot Airstream trailer—their home for the previous 5 years—into the new 500-square-foot guest house, a giant step towards leading lives closer to normal.
We then set about designing the main house, which was to be constructed with three areas of varying degrees of purity. The entry area would be where everything from the outside world came in—mail, groceries, visitors—and would be decontaminated if necessary. The middle zone would include the kitchen and dining and living areas. The purest area would be the bedrooms, so if someone were sick, the danger of additional exposure to toxins could be minimized. Air ventilation was designed to move from most pure to least pure. The overall shape of the house needed to be simple enough to be completed on a very modest budget.
SIZE: 1600 sf conditioned space
SITE SIZE: 42 Acres
COMPLETED: 2001
CONTRACTOR: owners
MAIN SUSTAINABLE FEATURES: Passive solar heating and cooling, concrete slab on metal decking for thermal mass, radiant floor heat, Tulikivi masonry heater with roof-mounted exhaust fan
BUILDING SYSTEM: The thermally broken double-walled steel frame (exterior walls 11" thick in total) rests on a suspended concrete slab on metal decking over steel girders and concrete sono-tube columns. The structure is insulated with blown-in fiberglass between metal studs and a 1/2"-thick layer of rock wool secured to the exterior side of the studs. The exterior is clad with fiber-cement siding and trim, with a metal roof. All exterior wood is locust from a local saw mill; no pressure-treated wood was allowed. Thermally broken aluminum windows were used to avoid the preservatives normally found in wood windows. Special-order gypsum board was used to avoid the chemicals used in the outer paper layer of regular gypsum board. Special mud was used with the gypsum board to avoid the toxic plasticizer used in the industry standard. No-VOC paints and varnishes were used throughout. A high-efficiency propane boiler is housed nearby in a separate building to ensure combustion products do not make their way inside the main house.