R. Buckminster Fuller's Geodesic Dome Design

Enlarge Image Image Gallery A geodesic dome design used for a botanical garden. PHOTO: FOTOLIA/MITCH AUNGER

Reprinted courtesy of Popular Science Monthly.

Can't wait until spring warms up enough for you to break out the swimming pool? Reluctant to close it in the fall when the air starts getting chilly? Here's a perfect solution: a plastic-covered sun dome over your pool. R. Buckminster Fuller's geodesic dome design makes it simple to build a 30 foot dome. It's the cheapest, simplest way to extend your summer activities. You'll be able to swim nine months of the year in most locations; all year, with extra heat. And you can build one for as little as $60.

On a sunny day, the temperature inside the dome is 20 to 30 degrees warmer than outside. And the heat's free; it comes from trapped solar heat, the same way as in a greenhouse. With a pool, the water will absorb heat from the sun during the day and give it off at night. This keeps it 10 to 15 degrees warmer inside the dome for swims at night and on cloudy days. A pool- or space-heater makes it still warmer.

But the benefits of an expanded summer aren't limited to pools. With a sun dome, you can start your outdoor barbecues earlier and continue them later in the season. As a greenhouse, it lets you grow colorful flowers the year round, or start tomato and other plants early. It's a fine outdoor winter playroom for the kids: There's room for a Ping-Pong table, picnic table, chairs.

Cover the dome with screening and it's a screenhouse. Put this over your pool, or over your picnic table and charcoal grill, and the delights of a summer's evening outdoors won't be spoiled by mosquitoes and other things that fly in the night.

The principle that gives this dome (called a geodesic dome) its remarkable strength was discovered by R. Buckminster Fuller. It's a patented design of interlocking tetrahedrons and icosahedrons that distributes forces evenly throughout the entire framework so that tension and compression forces are balanced. You could say that mathematics holds it up. That's why you can build it with slim sticks and plastic film.

The domes you see here were built by Ernest Muehlmatt of Xledia, PA. They're made of 1/2 inch by 3/4 inch strips of clear pine formed into triangles and covered with polyethylene film. There are only two sizes of triangles and everything is put together with a stapling gun. No nails or screws are used except on the door frame and hinges. You can build it in a weekend, and you can take it down in just a few hours for storage.

First Dome: a Greenhouse

Muehlmatt, a professional florist, built his first dome as a greenhouse. It is 16 1/2 inches in diameter. Excited by its possibilities, the editors of Popular Science asked him to build one big enough to go over a large swimming pool. We sent him one of the new Doughboy Silverline vinyl pools with interlocking steel framework. It is 18 feet in diameter and 4 feet deep. He made the dome big enough to give room to walk around the sides of the pool. It's 25 feet across and 8 feet 9 inches high. But it can be made even larger rising the same techniques.