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The underside of my front porch deck is in my heated basement and is generally a big loser of heat. It is a t&g deck over 2×6’s joists about 8’x 8′. The decking is always kept caulked and painted, but ocassional accumulation of moisture has ruined the vapor barrier on the insulation, exposing the fiberglass. The insulation bats seem to be loosing their efficiency as time goes on. I would like to re insulate the underside of the deck again, but this time using a product that will last a little longer. Initially the insulation seemed to do the job. Would the new encapsulated bats be the answer or how about blue board? I believe the majority of moisture damage was caused by condensation as a result of poor sealing of the vapor barrier
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Blue board. Definatley the way to go.
You can get pink board as well. It is a bit thicker, and better r-value. I'm sure there are others here who know all about the different types of foam board available.
*Blue board is fine - just remember you have to sheetrock over it (flammable) in most code jurisdictions. I'll bet that some of the 'moisture' is actually leaking through the decking.
*Jeff, I agree that some of the moisture is coming through the decking, no matter how well sealed the surface appears to be. But the sheetrock and the water definitely won't get along either. This seems to be a "catch 22" situation. How can I insulate, yet not be concerned about ocassional moisture, and the flammable issue?
*David,I second the motion. Inevitably you will get some moisture through the deck. Crane Products makes a product called DrySpace to keep the area under a deck dry so you can use it in the rain, etc. Looks like a 16" wide vinyl that snaps into an F-channel on either side like soffit. Then you could insulate under that.Or staple some 6 mil poly up....
*Besides drywall, what are my options to cover the blue or pink board to fire proof it?
*Sheetrock!Otherwise.....?
*Hey Doc, thanks for your thoughts.
*i Foil-backedsheetrock?
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The underside of my front porch deck is in my heated basement and is generally a big loser of heat. It is a t&g deck over 2x6's joists about 8'x 8'. The decking is always kept caulked and painted, but ocassional accumulation of moisture has ruined the vapor barrier on the insulation, exposing the fiberglass. The insulation bats seem to be loosing their efficiency as time goes on. I would like to re insulate the underside of the deck again, but this time using a product that will last a little longer. Initially the insulation seemed to do the job. Would the new encapsulated bats be the answer or how about blue board? I believe the majority of moisture damage was caused by condensation as a result of poor sealing of the vapor barrier