Vapour barrier behind plaster (removed chimney)


Old 09-26-14, 08:47 PM
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Thumbs up Vapour barrier behind plaster (removed chimney)

I have a unique situation I have removed a chimney and the 1ft wide horizontal "pre drywall" is visible from the outside. Inside the room is plaster. House was built mid 60's. There seems to be no good way to vapor barrier this cavity. it is about 9ft tall and 16" wide. There is no good way to get plastic in there with out leaving gaps for moisture to get through. My best thought is to use some rubber roof repair spray in the cavity, then put some fiberglass in. Covering up with plywood and some aluminum caulking the edges.
The whole point behind removing the chimney is it was falling down and leaking, the roof needed redoing. The fireplace in he basement is being removed.
I was really hoping to have taken down both chimneys while redoing the roof but the damn furnace will not die.. lol.
I would live to spray foam this but that is cost prohibitive.
Hopefully someone has some comments or other possible options. To me the most logical option is the rubberized roof patch spray and insulation.
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Old 09-26-14, 09:34 PM
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Plaster houses typically never had any vapor barrier to begin with, so if the rest of the house doesn't have one, I don't think I'd be too worried about the 16" that you've exposed. Insulation typically has a vapor retarder that faces the interior (warm) side.
Old 09-27-14, 04:54 AM
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Install fiberglass that has a craft paper face.
Old 09-27-14, 06:34 AM
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I don't have a clear picture of what this looks like, but vapor barriers are less important than air barriers. If you ensure that warm house air cannot come in contact with cold surfaces, directly or through the insulation, then there will be little risk.

Can you post some pictures?


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