Superinsulated Geodesic Dome
The dome is for sale. Here's its listing on Trulia. We're asking $250,000. That's a lot of money for a house in Fairfield, but it's a rare house that has this level of thermal performance. The few that do tend to cost more than $135/SF. Our hope is that someone with an artist's eye and an engineer's mind will recognize our dome's particular advantages. These include:
- Insulation -- There's ten inches of spray foam insulation. The top of the dome is all closed-cell foam, for an R-60 "roof." Closer to vertical, it's open-cell under an inch or two of closed-cell, for R-40 "walls." Spray foam stops air infiltration more effectively than other forms of insulation, for a comfortable, draft-free home. Before the radiant floor was hooked up, two 1500 watt space heaters kept us warm in the coldest weather. This means the dome only loses around 10,000 BTUs/hour. That's very low for an 1850 SF home.
- Longevity -- The surface is covered in copper-colored Reinke aluminum shakes. Any house with asphalt shingles is a house with an expensive roofing job in its future. The Reinke slogan is "Shingle for the last time!" and with this dome that's already done. Take a look at Reinke's Hail and Tornado page if you need further convincing.
- Strength -- What good are shingles that won't blow off if the whole house blows over? Spheres are stronger than cubes, and triangles are stronger than rectangles. A sphere made of triangles is a very strong structure, and domes regularly survive tornadoes, hurricanes, and straight-line winds that destroy conventional houses.
- Health -- Iowa has the nation's highest radon levels, but this house has a radon pipe. It tested below 4 pCi/L with the ventilator turned off for a week. Normally, the Energy Recovery Ventilator would be delivering fresh air, expelling stale air, and further reducing radon levels. Another health benefit: solar heat with electric back-up cannot cause carbon monoxide poisoning.
- Beauty -- This is of course subjective, but we've had many compliments on the dome's appearance, both inside and out. It can feel very uplifting to live in a home with high ceilings that curve like the sky.
The front door and driveway:
The living room's flooring is Marmoleum Click, color African Desert.
The west end of the living room becomes the kitchen:
The loft in art gallery mode:
Marcia hand-glazed tiles and installed them behind the kitchen sink and in the shower:
Steve's studio, which we're calling a bedroom, is 211 SF including the closet and half bath:
Marcia's studio, which we're also calling a bedroom, is 295 SF including the closet:
An investigation into local real estate conventions suggests that the 9' x 14' room we actually used as a bedroom can, in fact, be counted as a third bedroom. While it has no closet or window, it has a fresh air duct and two doors for emergency exit. When you open the doors, you see windows:
Floor Plan. The shaded area is the loft.
Double-wall construction minimizes thermal bridging:
The dome at dusk:
More photos at our listing on Trulia.