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Dilemma : Basement Spray Foam but No capilary break
Got a poured concrete foundation near Ottawa Ontario. Am doing the basement and was going to go all in with spray foam R-20 full height with joist cavities sprayed...
However, the house has untreated sills resting on the concrete wall, with no gasket. As well, the foundation is only dampproofed. I am concerned about covering the sill plates in this situation ...
Is there rotting potential? Some internet resources seem to think so. Others say the wall may dry to the outside above grade..
For the most part, the foundation is 2 feet above grade, but there is a 10 or 12 feet place where the grade was raised to about 8 inches from the sill. Sill gaskets or treated plates are only required here when <8 inches from grade or below grade..
I removed the builder insulation (R-13). Around here most basements are done to nominal R-13 with batts. Tar paper is applied to the inside of the concrete wall to about grade, and poly VB on warm side. They stuff batts in the joist spaces and cover with poly. They are typically poorly detailed which migh actually be a good thing since the VB is not perfect and things can dry to the interior!
My current thinking is to do full height R-13 closed cell, and do the joist spaces myself with Roxul batts or ComfortBoard, and VB.. The idea that it would be open for inspection (areas that are not drywalled), and I can control the details if needed.
Any thoughts or experience with this?