Hi—building a new home in climate zone 6a. The poured concrete basement walls were damped proofed with a liberal application of non-fibered tar coating, and then insulated with 2” xps on the exterior. The foundation walls have interior and exterior drain tile, were liberally backfilled with 3/4” clean stone, then sand, and the top grade will be sealed with clay soil. The build site is a sand knob, with very well drained soils. I live adjacent in an old farm house with rubble walls and that basement has always been dry without a sump pit or drain tile. 

The basement walls were poured in November. We had an unusually warm and dry winter, so I believe most of the “internal” water from the new concrete has dried. 

A portion of the basement will be finished for two bedrooms, a bathroom, and a rec room. We are nearing the point where we will be framing the finished areas. My plan was to install 1.50” foil faced EPS tight to the foundation walls with taped seams, then install 2×4 stud wall, possibly install 3.50” of mineral wool in the cavity, and then finish with 1/2” gypsum board with veneer plaster finish, then paint. I was not planning on installing an additional vapor retarder before drywall. I’ve read a multitude of conflicting articles as to whether a vapor barrier facing on below grade interior foam sheets is a good or bad idea. The FHB article on three ways to insulate your basement says poly should NOT be placed against the concrete. A foil facer is about as vapor restricting as poly, so I’m questioning my choice. The caveat with this article is that none of the methods shown in the FHB article has exterior insulation. I would think the 2” layer of xps on the foundation exterior will keep the inside face of the wall warm enough to prevent condensation, but still not sure if any moisture from the concrete walls will be unwisely trapped by the foil facer on the interior EPS. Thoughts?