Hello. I want to insulate/air seal my basement walls. Hous built in the 50's. Brick walls. Clay soil. Located in SC. When we get several days of rain, water starts leaking through the walls. I have applied drylock which helped, but hasn't stoped the water leaking. The basement has a drain in the middle of the floor so the water drains out without any help. I'm wondering if I can cover the floors & walls in plastic then foam board. Will the allow me to finigh the room and hide the moisture or will it just create a mold problem under the plastic/foam board? thank you!

It's really important to deal with the bulk water issues first, or it'll come back to bite you. When it can't dry toward the interior, letting the concrete run saturated for days on end can load up the foundation sill with moisture. If you want to jack up the house and slip in an EPDM or metal capillary break between the concrete and foundation sill you can get away with most anything though.

On a house with that type of history, when you get it to the point where you don't have visible moisture coming through the wall after torrential rains, it's still worth using dimple-mat vapor barriers rather than sheet poly between the wall and the foam, and cutting an interior-side perimeter drain below slab level, draining either to your existing drain or a sump.

good to know.

thanks!