On Mon, 20 Aug 2012 22:23:07 -0400, wrote:

On Mon, 20 Aug 2012 18:55:49 -0700, 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.
Virtually NO concrete floors in years past had vapour barriers or
insulation . You just need good drainage underneath.

In the Midwest vapor barriers are normal under concrete floors. My parent's
house had it under the house they had built in '59. It's not new.

Adding a Dri_core subfloor is the simple and effective way to put down
a tile floor (or vinyl, or carpet) on a concrete floor.