Trying to insulate basement walls, don’t want to end up with black mold in walls. Any advice is greatly appreciated. I live outside New York City in climate zone 5. I have 2 exterior walls, one has a 4in sewage drain pipe running across it. On wall with pipe I’m going to put 2 layers of pink foam board so it is flush to pipe. (4in foam) On wall without pipe I will use 1 inch pink board. I will then build 2×4 walls in front of foam on both walls and fill bays with unfaced insulation. Not sure which one to use here.

I also have interior foundation walls separating areas of basement. On those walls I want to put 1/2 inch foam board just to separate 2×4 wood wall from concrete. I will not be filling bays since it is an interior wall.

I have seen an example where someone built this exact setup but then put a plastic vapor barrier over entire wall before putting drywall. Am I suppose to use no vapor barrier, I have read people doing it both ways. If I understand this correctly putting plastic is like making a gigantic soggy diaper.

Thanks,
Joe Diyer