Is the airform technology used in monolithic domes still in a perfection stage? The airform technology used to build monolithic domes is in a constant state of improvement, but the domes don't lose heat and they are as "green" a green building as you can get!
When new technology becomes available to the public, it often is not yet perfect. Prototype designs are expensive and very prone to failure. Over time, as the free market drives competition and manufacturing of the device becomes more routine, the number of problems falls, and the number of optional features may rise. The item becomes easier to build,and therefore much cheaper.
For example, home electronics have come a long way in the last few decades. Video cassette recorders and DVD players were priced at nearly a thousand dollars when they first hit the market. But as production and sales increased, and as the technology behind the devices improved, the price rapidly dropped, and today, DVD players are very affordable, with prices as low as $30.
The Airform technology used in building a monolithic dome home was pioneered by David South, the founder of the Monolithic Dome Institute in Italy, Texas. David has been building domes since 1957, and monolithic dome homes for over thirty years. But even with that much history, he feels that some elements of the process are still being developed.
Monolithic domes are made of concrete, and concrete requires some form of mold or pattern to pour it into. An Airform is a method of forming a mold for the ceiling of a dome. The Airform is basically a plastic balloon custom-built according to the design plan of the house. High-velocity fans pressurize the house and inflate the balloon, and hold the airform in place long enough to spray the inside of it with three to five inches of polyurethane.
Once the polyurethane sets,which only takes a few minutes,rebar can be fitted. The rebar and the polyurethane combine to form the "mold" for the concrete. Liquid concrete is sprayed up into the mold, and as it hardens, it forms the last and strongest layer of the dome.
The Airform becomes the outside shell of the dome. The middle polyurethane layer forms a waterproof barrier, protecting the concrete from the elements. The concrete, besides providing the form and strength of the dome, also provides a very dense layer of insulation,and this is one of the primary selling points in dome homes.
Airform technology is still in the perfection stage, David South says, "and it will be for a long time before we have what we call 'perfect,' but we are gaining every day." Every new technology has "wrinkles to be ironed out," but in the case of monolithic dome homes, there really are wrinkles! "Mostly we get some wrinkles [in the airform] that we wish we didn't get because they're not as pretty as a smooth finish."
Even if the technology isn't up to his standards of perfect, there are still plenty of benefits with the existing technology. For example, a dome requires less than half the materials of an "old fashioned" wood frame home.
David makes it clear that dome technology is perfectly sound, and the improvements they're trying to find are basically cosmetic. One of the major factors in choosing a monolithic dome is heating; the concrete form provides a very high level of insulation, and domes generally cost half as much to heat as an equivalently sized home. "It doesn't lose heat," he says. "That part of it we've got licked."
