Regarding basement finishing, my basement has no framing, and along the foundation walls from the top down 48 inches the builder has installed a product called Polytarp Supersix. For those not familiar, it is essentially batt insulation with a 6 mil polyethylene adhered to one side. It is installed insulation side directly against the concrete foundation wall. The top is sealed with Tuck Tape to the standard vapour barrier, and the bottom is nailed into place. It has an insulating value of R8.

The issue I have noticed is water behind this product on the surface of the poly, and then soaking into the insulation. I believe the water is condensation, because it dries up during the winter, and is not present in the spring after heavy rains. There is no pooling of water in the basement either. We have been experiencing weather for some time now in excess of 30 degrees Centigrade, or 90 degrees Fahrenheit, so of course, the air conditioner is running, and the basement is cool.

I am about to finish my basement, and I want to know if I should remove this product prior to erecting the perimeter walls, or will this condensation issue resolve once I erect the perimeter walls? My intentions were to insulate and vapour barrier the perimeter walls as per normal.