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Re: GBlist: vapor permeability

You have several options & they depend abit upon your climate. The poly or
sheet vapor retarder (as it is now called) is time consuming & difficult to
achieve a complete seal.

You might consider a sprayed insulation - icynene, cellulose, air-crete,
etc. Icynene is already a vapor retarder material, while the others are best
handled with a vapor retarding primer. Another option might be dense-packed
cellulose, right thorough the drywall or a rigid foam board on the interior.

If you don't have to have a stick built house - there are several stress
skin panel and other modular elements that have vapor retarders built into
the system.

Vapor & moisture problems, while dependant upon climate, are also
exacerbated by pressure issues - is the house ventilated correctly ? ... is
the forced air system balanced and air-sealed ? ... is the envelope tight or
leaky ??

need more ???
Frazer Dougherty                doughf@mindspring.com
North Fork Retrofit             doughf@aol.com (fallback)
website: http://www.home-performance.org


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