This do-it-yourself house is a sophisticated energy saver
The Cherokee Indians recently gave the nod of approval to a housing system that combines an age-old construction technology with a modern one previously used only in high-rise buildings. As a result, energy-efficient, easy-to-build, more-affordable houses should soon be available to Americans everywhere.
Post-and-beam framing, once widely used in Europe and in early America, has been paired with an insulated wall-panel system used in high-rise construction for the past decade. The result is a home that can be heated and cooled for less than $300 a year at current electric rates. It can be erected by three people with modest do-it-yourself skills in a week, or by a skilled construction crew in two or three days.
A few years back, the Cherokee Nation in Oklahoma approached the Institute of Man and Science and asked in effect: ''Can you do anything about our deplorable housing?'' They did not feel existing construction was giving them very much for their money.
The nonprofit institute, based in Rensselaerville, N.Y., assigned the problem to its engineers with these demands: The designs had to be energy efficient, readily erected, and simple enough that homeowners with modest skills could build the basic structure on their own.
By adapting modern steel and foam wall panels for use with centuries-old post-and-beam framing, the designers met these requirements. The panels are made by chemically bonding closed-cell polyurethane foam between two lightweight steel skins. Polyurethane (in no way related to urea-formaldehyde foam, which can give off irritating gases) has an insulating value more than double that of fiber glass.
The rules governing a nonprofit organization forbade the Institute of Man and Science from marketing the product it had developed. So Pond Hill Homes Ltd., of Blairsville, Pa., was established to manufacture and market the components, which are pieced together at the building site. A Pond Hill home, in other words , is not so much built as it is erected.
This how a Pond Hill home would go together:
Foundation. The designers recommend that the foundation, whether full basement, footings, or crawl space, be done professionally unless the owner-builder has ''strong masonry skills.''
When this is complete, all the materials for the basic home envelope - wood frame, polyurethane panels, exterior doors and windows, interior stud walls, exterior finish of the owner's choosing, a complete roof, and air-to-air heat exchanger - are delivered to the site with a manual giving the step-by-step erection process.
Framing. About 60 wood members, all readily handled by two people, frame the entire house. Post and beams for the sturdy exterior frame are precut and coded for ease of installation.
The interior stud walls that support the ceiling beams are prefabricated and are the first to go up. On completion, the posts and beams remain exposed on the inside walls and ceilings to provide the look and atmosphere generally associated only with vastly more expensive housing.
The wooden members are held in place by inserting dowels into predrilled holes. Finally, the joints are reinforced with steel connector plates. Trials, using unskilled labor, suggest that the framing system should go up within one day.
Ceiling panels. With two others to help, the builder should get the ceiling panels in position and fastened in half a day. Thereafter, the sturdy panels form a solid and safe platform from which to erect the roof trusses. On its own, the foam could not support the weight of a man, nor could the thin steel skins. But in combination, they form a very strong, rigid panel that readily supports such weight.
Exterior walls. The 3 1/2-foot-wide panels, stretching from floor to ceiling, are nailed in place to the wooden sill and header. With one helper, this should take about a day. Special panels to accommodate doors and windows are included in the package.
The precision-made panels lock together so tightly that they form an effective vapor barrier and a continuous shield against infiltration of cold outside air. The home is so tight, in fact, that it is recommended that an air-to-air heat exchanger be installed to keep interior air in an acceptably fresh state.
Roof frame and finish. Conventional prefabricated roof trusses are placed two feet apart down the length of the structure. These are covered and finished in the conventional manner. Completing the roof is one of the more time-consuming operations, taking two people about six days.
Interior. Adding the ceiling and perimeter dry wall (gypsum board), modular interior walls, thermal windows, and doors should take 3 1/2 days to complete.
Exterior finish. Attaching the siding chosen by the buyer is the final step in completing the basic envelope of the home. It will take from two to four days , depending on the type - vinyl, aluminum, or wood. Stucco or paint can also be applied directly to the panel surface.
Completing the house envelope (walls and roof) is not the same as completing the house. Plumbing, electricity, and some finish carpentry must then be done by the homeowner or contracted out. But, protected from the elements, the remaining work can be readily and comfortably completed whatever the weather.
Because the home is so well insulated, a simple portable space heater will provide all the warmth needed by workers even in the depths of winter.
Kits start at $9,000 for a 756-square-foot house or $10,400 for one of 924 square feet, which works out to around $11 a square foot. The larger the house, the lower the cost per square foot.
While accepting orders directly from customers, Pond Hill Homes is also looking for qualified builders who could represent the company in other parts of the country. Send inquiries to Westinghouse Road, RD 4, Box 330-1, Blairsville, Pa. 15717, or phone (412) 459-5404.