Quote:
Originally Posted by BroadHopper
Only other big leak was the dryer vent. There is no way of stopping that.
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Energy Star homes have 1 inch of foam insulation followed by fiberglass or cellulose batten covered with a thick plastic sheet. Sheetrock must be added without strappings. There will be a moisture problem between the plastic sheeting and sheetrock. A number of sheetrock contractors turn down the job because they insist on strappings. Saying sheetrock goes on better.
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There is one dryer vent I know of that works well against drafting back into the house, the Heartland Dryer Vent. It's available by Internet for around $20 shipped. Easily found via Google.
The described combination of foam followed by a porous insulation isn't specific to the Energy Star program. That "flash and batt" approach is but one way of providing air leakage protection and insulation level that meets code. Energy Star does say that porous insulation such as a fiberglass batt must be up against the confining surfaces on all six sides, with no void spaces that would permit convective flow of air currents.
Having a sheet of poly between the insulation and the sheetrock as a vapor retarder also is not a requirement of any US building code or Energy Star. It can cause problems in hot humid weather if the A/C inside is turned down too low, as condensation can form inside the wall in such conditions. All that is required here is a 1 perm vapor retarder, which can be a vapor retarder primer paint. The permeability of a sheet of polyethylene is so low as to be called a vapor barrier, something not needed except way up in Canada or Alaska.
Installing sheetrock over strapping or directly onto framing members is a purely regional thing. Builders in the NE tend to do it with strapping on ceilings, while elsewhere no strapping is used.