Bentonite on basement walls
I recently bought a house in Marine 4C climate zone that has an east facing daylight basement. The previous owner installed an interior french drain that drains into a sump pump. The drainlines for the downspouts were rerouted from the front(west, which slopes slightly into the house) to the north and south sides. The problems they were trying to resolve have apparently been fixed because the interior concrete walls of the basement are not damp and the sump basin is bone dry after above normal fall and winter rains.
I intend to finish the basement with a combination of foam insulation boards attached to the concrete walls and blown-in cellulose in stand off 2×4 wall cavities. I had always intended to use geotextile bentonite fabric or panels or trowel it on as a mastic on the surface of the concrete walls to prevent the possibility of moisture penetration. My question is this: Is bentonite a choice for front line defense against water penetration and do I need a vapor barrier between the bentonite and the foam board? Most applications of bentonite are on the exterior of the foundation walls. Does bentonite work on the interior surface or would water pressure make it peel off the walls? The stuff is not very sticky and getting it to stay on the walls in the first place is difficult. It must require wall prep and additives. Will bentonite sheets or mastic work on a concrete slab and will any floor finishes adhere to it.?
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