Basement Insulation / Vapour Diffusion

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Basement Insulation / Vapour Diffusion


A couple questions: Would there be any drying issues with insulating a greener foundation (Nov.2012) on two sides with foam? - Are we asking for trouble at the sill ?

We were planning to heavily insulate our (new house) basement with XPS on the exterior only, but may end up with additional foam in some areas of the basement interior as well, depending on how it's to be used / finished. The small mechanical room, for instance, could get EPS (type II, 2 1/2'') under plywood on the interior.

I know that the moisture in the concrete needs to go somewhere at sometime, and with the potential for such complete sealing around at the sill / rim joist area with spray foam, and possibly foam on two sides, can that (or future) moisture in the foundation still effectively dry, in or out ?

Also, as an aside, can anyone verify if longer lengths in IDP type foam fasteners are available ? -While we located one listed online (HILTI), they informed us that the product is not available.
We are hoping to locate some IDP's long enough to secure two layers of reclaimed 3'' EPS panels (2'x4' w / shiplap) to the outside of our foundation in one shot. The longest ones we found were just 4 1/2'' overall.

Thank you,

Asked by jessie pratt
Posted Mon, 01/21/2013 - 12:13