I have a crawl space that is about 3 feet high, dirt floor, nothing in the space but ductwork and wires and some plumbing (no air handlers or hot water heaters). It has vents in the masonry along the edges.
My question is this - right now, there is insulation between the floor joists above with fiberglass insulation and a paper vapor barrier to the warm side of the floor (interior). For whatever reason, about 1/4 of the crawlspace does not have insulation over it. I know most people recommend a plastic sheet over the dirt floor as a vapor barrier, but with my situation, wouldn't that create a double vapor barrier? Should I insulate the remaining crawlspace the way it has been done so far? I don't know that I want to rip out the other insulation just to put plastic down, as the crawlspace is about 1000 sq ft. Or should I leave the vents open and put down the plastic as well?