I'm doing some work on a home has a slab crawlspace whcih has a few inches of water in it-it's a bank repo so no electric/pump to get rid of water.
the kitchen floor is a DIY installation-has 1/2" plywood installed over the original vinyl flooring and a failed installation of 12" tile. The tile comes up easily-poor adhesion between plywood/thinset. As I'm tearing into it, by the exterior wall I find previous signs of delamination in the original layer of plywood and the top layer of plywood is moist. failed tile adhesion is obviously b/c of high moisture content in top layer of plywood.
the question is: why is the top layer of plywood wet? afte pulling some of the vinyl sheet flooring back, the subfloor (or luaan) seems to not be wet. no signs of water coming into the room from the exterior wall. could the moisture be coming up through the wet crawlspace, then stopping at the bottom of the 12" tile and soaking the top layer of plywood?
I'm stumped as for a logical conclusion to this.