We're planning on finishing our basement...going to attempt it myself. Right now its a slab floor with block walls that are have batts and blanket type insulation nailed on (this is how it was when we moved in). There is also a french drain. The basement is dry - we've never had any issue with water, and I've never even heard the sump pump go on (though i've confirmed it works). Occasionally after a rain event, however, the blocks on the wall do turn dark. This is not very often, however. I've tried the taping of the plastic onto the floor - no moisture. My next step was to try the wall to test that as well.
My plan to start is to seal the french drain (using PVC and grout), and then frame the walls as normal. Does anyone have any experience with this? Are there any potential problems with sealing the french drain in this manner? I'm thinking with the PVC in there - the drain will still be able to move water coming in from outside the foundation towards the sump. Also - should I go through the process of pulling the insulation off to put some sort of water-proofing on the block walls before I begin to frame? Is there anyway around doing this? COuld i just cut some holes in the dry wall after I've framed it an put some vent covers over it to provide some ventilation to behind the framing?
Any advice would be appreciated...thanks!