On Tue, 21 Aug 2012 02:31:23 +0000 (UTC), gregz
wrote:

G Mulcaster wrote:
On Sun, 19 Aug 2012 19:38:25 -0700 (PDT),
wrote:

I recently put down peel and press tile on a section of my
basement.....big mistake. There is just too much moisture in the
basement. The tiles are loose and there is black mold. I'm going to
lift up the tiles and toss them. What should i use to clean the
concrete. I seem to recall that bleach is good to kill mold.

Mix 1/3 bleach and 2/3 water in a garden sprayer. Spray on floor.
Rinse off after 20 minutes. (I sometimes just let it dry on its own)
Ventilate well.

It would appear the cement has no vapor barrier underneath, or it has
failed. The tiles are now the vapor barrier and moisture wicking up
has caused them to lift.

Prior to the tiles, the moisture wicking up would have been been
absorbed by the ambient air and not noticed.

To check for a vapor barrier, tape a 2' square piece of polyurethane
to the cement. If you can see moisture forming on the underside of the
poly within 48 hours, there is no vapor barrier. An easier way is to
fill a large garbage bag with clothes/towels and leave it sit on the
cement for two days. It should remain dry underneath.

There is litle that can be done in terms of fixing the root problem of
a missing vapor barrier. You could ask a flooring professional about
installing someting over the cement to act as a vapor barrier; for
example, seam free lino with waterproof glue. Ceramic tiles may be an
option if they are the porous type.

There was no vapor barrier in homes around here. Mine is 1953. Sand
underneath.
It was up to the builder to provide proper drainage. They didn't even use
barriers on cinderblock up against dirt. If the water table comes up, you
will have water seepage. Many people install aftermath French drains and
pumps.
I'm fine pretty much. I can see old remnants of paint still on my floor,
most of it gone. Moisture will come through cement. Currently going to
install rugs and flooring, on top of marine foam insulation, with top layer
of strand board. All foam taped and sealed for moisture seepage. My
basement floor is not wet, else I would install pumps.

Greg
MUCH better than marine foam is the waffled plastic like is used on
the outside of block walls for drainage. Same stuff as on the back of
DriCore. And cheaper than dricore. We put 14mm bamboo interlock
flooring directly on the waffle, without sheathing .