"Eigenvector" wrote in message
...
Strange situation in the basement of my house. The basement has had a
known water problem, the previous owner "fixed" it with a french drain on
the uphill side of the foundation and that did appear to halt water
seepage. After installing the french drain he covered the basement with
wood flooring, supported on 2x4's. I can only guess how long the flooring
has been there, 1980's possibly earlier, but right now I'm in the process
of ripping up the flooring. The concrete under it doesn't appear water
damaged, although the boards used in the flooring are well into a decayed
stage and dry rotted to heck and gone. So there is the history, during my
remodeling of the basement I leaned drywall sheets up against the
foundation walls to keep them out of the way. Anyway, I have begun to
clean up the area and noticed that in one spot there was moisture dripping
on the flooring, mold (the white fuzzy kind) on the concrete, and fresh
signs of efflorescence and moisture on the foundation - but only in the
spot where the drywall was touching the wall. There were also about a
zillion angry spiders too, one of 'um big enough to challenge me to an arm
wrestling match - I declined the challenge.

It was only in one spot, and only where the drywall was leaning against
the concrete. Was the drywall attracting water through the concrete, or
is this a completely coincidental situation. I can deal with a water
problem, I suspect it exists regardless of this particular occurance, but
I wanted to be sure of the cause. I want to add, that the flooring where
the water was seeping through prior to this had NO signs of water damage.
So whatever the cause its new and not something that has shown in 30
years. Unless of course the drywall was acting as a drip path for the
seepage, whereas normally the water would drip down the wall and pool
under the flooring.

Water passing through basement walls and floors often just evaporates
unnoticed into the air if its passage is not obstructed. Testing for water
penetration is done by taping a square of plastic to the wall or floor for a
day or so and seeing if it gets damp underneath. I suspect you have a water
problem which will have to be dealt with before you seal up the floor or
wall again. You can use the plastic test to determine if and where the water
is coming in.

Don Young