Question - I was recently in a large, super-insulated geodesic dome home. Are the utility bills really 50 percent less than a conventional house? Could I build one myself to lower costs? - D. S.
Answer - Yes to both your questions. A geodesic dome house is naturally very efficient. Various kits, up to 5,000 square feet of floor space, are designed specifically for the inexperienced do-it-yourself builder.
Geodesic dome houses have interesting room shapes, 20-foot high angled ceilings and many skylights. This produces an open spacious feeling. By adding dormer, window and room extension kits, they look more conventional.
There are three do-it-yourself dome kit building methods. Many use a steel hub and wood stud system for the frame. Precut, predrilled lightweight hubs and studs are color-coded and bolt together like a huge erector set.
After the foundation is built or poured, several workers can enclose the shell over a weekend. None of the kit parts weighs more than 25 pounds. Most kits include everything needed - all studs, nails, bolts, plywood, etc.
One kit (Natural Spaces) uses double studs construction for up to a R-62 super-insulation frame. Once the basic structure is completely bolted together, the framing is covered with precut color-coded plywood triangles.
Another simple construction method uses precut foam insulation panels covered with a layer of reinforced concrete. It is so strong when complete, that the kit warranty covers tornado, hurricane and earthquake damage.
First build a temporary kit frame. This is for support only and is removed when the home is complete. Recycle the frame lumber for interior wall studs.
The precut panels are computer designed to join perfectly at the edges. A three-inch deep channel at each edge is filled with concrete and reinforcing mesh. This forms a strong concrete shell with R-35 insulation.
Another building method uses similar foam panels that are glued together at the edges. The exterior and interior are sprayed with a cement material for strength and a finished look. This is also extremely airtight.
The key to a dome's low utility bills is its shape. With 30% less exterior area than a rectangle house of the same size, it wastes less energy year around.
Winds pass smoothly over the dome, minimizing air leakage. The interior dome shape creates a natural flow of air indoors to improve heat distribution. This is ideal for passive solar, wood or space heaters.
Write for Update Bulletin No. 903 showing a buyer's guide of 10 dome house kit manufacturers listing size and price ranges, typical specifications and six floor plan layouts and exterior diagrams ranging from 1,200 to 4,000 square feet. Please include $2.00 and a business-size SASE. Write to James Dulley, Deseret News, 6906 Royalgreen Dr., Cincinnati, OH 45244.
Question - I am building a batch solar water heater that you described in a previous column. Is it best to use dowels to join the pieces or are just glue and nails adequate? - W. V.
Answer - If you have the time and patience, it is a good idea to construct any type of wooden solar heater with dowels instead of just nails. The temperature and humidity levels in the lumber of a solar heater vary greatly from day to night. This can cause warpage and looseness from repeated expansions.
A trick to make old, sometimes swollen dowels fit tightly is to drive them with a hammer through a machinist drill gauge. This accurately resizes them.