jan siepelstad wrote:
did you check for a cold spot in the floor, where water vapour which is in
the air, is condensating?

The floor doesn't seem colder there than anywhere else, but....

Up until just a day or two before we discovered the wet spot, it had
been very warm and humid, almost without a break, for several weeks.
Does it sound possible that the humidity in the air penetrated through
the carpet and the pad, contacted the tile-on-concrete floor, and
condensed out? In this scenario the fact that it's at a high spot would
be irrelevant; the main issue would be that it's a cold spot. No one
was in that room for several days before the discovery, maybe even a
week.

Hydrostatic pressure is also still a prime suspect, but jeez, it was so
dry here all summer! Could condensation have happened as described
above despite the barriers of the carpet and pad?

Also...if it is hydrostatics, is there some kind of sealant or barrier
I can use to block the water...without having it come up someplace even
less convenient?