VentilationWall Cavity |
As leaders and pioneers in the field of dome home technology, Natural Spaces has developed a dome wall ventilation system that provides for continuous natural air circulation over the entire fiberglass insulation surface. |
 Air enters at the bottom of the dome shell through a flared base vent skirt with screening, rises as it is warmed by the sun, and escapes out of the top low profile vent cupola. The air being vented carries with it any moisture-laden air that has migrated into the wall cavity from the inside of the dome. Most other dome companies ignore the condensation problem or simply don't know it exists. Almost all of the building codes call for a vented air space on the cold side of the fiberglass insulation in any cathedral ceiling. All building codes require ventilation of attic spaces. Dome companies that use rigid insulation, cutting it to fit within the triangles, may have a serious condensation problem because the insulation board does not fit tight to the outside panel. This leaves a perfect space for vapor to condense on the outside panel. (This holds true except for coastal areas and the far south.) The only kind of insulation not subject to this problem is sprayed in place urethane. This material, when properly applied to dry wood, does not allow vapor to penetrate. However, there are other problem details to be dealt with correctly. Urethane is also much more expensive than fiberglass. Talk to us, after 25 years of building them, we know domes. We live in Minnesota with a 150 degree temperature variation--we know weather. Our ultra-insulated dome system works in cold climates as well as hot climates. Building a warm dome doesn't just mean more insulation. It's many things, like our vented dome shell, insulation placement, caulking details, TyvekŪ Housewrap, 6 mil plastic vapor barrier, foundation wall insulation, triple and four pane windows, internal heat re-circulation, and other items. Our warm dome is economical to build. We don't want you sitting in your warm dome worrying about how you are going to pay the mortgage. We want you sitting in your warm Natural Spaces dome chuckling about your neighbor in his cold, conventional, expensive house. Condensation Condensation can be described as the change in moisture from a vapor to a liquid. water vapor within the house can migrate through the wall or ceiling during the heating season to some cold surface where it condenses, collecting in the form of ice or frost. During warm or sunny periods, the frost melts. When conditions are severe, this meltdown in unvented spaces may drip to the ceiling below and damage the interior finish. Wood sheathing may swell up. Insulation becomes wet and looses it's resistance to heat loss. These problems can be reduced or eliminated when proper construction details are used. The control of condensation through the use of vapor barriers and ventilation should be practiced regardless of the amount of insulation used. The use of both inlet and outlet vents in attic and roof spaces aids in keeping the air moving and preventing the accumulation of frost or condensation roof sheathing in cold areas. "Dead" air pockets in the roof can normally be prevented by good distribution of inlet vents in the soffit areas. However, there is still a need for vapor barriers; ventilation alone, when insulation is used, does not prevent condensation problems. |
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