Basement – Foam Board
Suz888
| Posted in General Questions on
I’m redoing my basement due to mold issues. I’ve taken care of external water sources (sewer, drainage, etc), and I plan on using the Foamular NGX next to the concrete for insulation plus rockwool. Do I need to apply drylok or xypex to the below grade concrete before installing the rigid foam board? Or can I just have the rigid foam board next to the concrete without treating it and assume the foam board will block any moisture? This is a 100 year old house in Seattle.
Thanks,
Suzanne
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Replies
You can put the foam up directly against the masonry wall. The foam board doesn't care if it gets wet, and it will block (or at least significantly reduce) vapor migration through the wall into your indoor space. I would only bother with Drylok or similar if you want an extra layer of protection in case of ocassional bulk water problems. If you are pretty confident that you have solved any bulk water issues, then you don't really have anything to worry about.
Bill
Thanks! Since the framing is already there, I can't place a sill sealer under the sill plate. Should I try to place some spray foam between the sill plate and the foam board? It is a treated sill plate, but I'm still worried. . .