I am remodeling a basement and have moisture migrating thru the slab. When anything
plastic sits on the floor overnight moisture forms under it. Is there any product that
will seal the floor & prevent this or should I just try to control the humidity in the
room and hope the slab dries out? This is not a new house but we recently corrected drainage problem along one wall.
Edited 6/10/2004 5:07 pm ET by DP
Replies
Moisture can certainly migrate through concrete. I have seen it emulsify the glue in a vinyl composition tile floor. You should try to eliminate the source of the moisture, rather than seal it in. Was a vapor barrier installed prior to placing the concrete? Did the mason poke all sorts of holes in it to cure the concrete faster? Does grade slope away from the house? Is there any underslab piping that could be dumping water into the underslab area?
There are systems available to seal the floor, but first you have quantify how much moisture is migrating through. Do that by performing a calcium chloride moisture test.
http://www.taylorflooringtools.com/prod20.html
A typical slab calcium chloride test result might be 3-5 pounds. About the worst floor condition you could seal would be 20#. Depending on where you fall in there, different systems will apply.
One source for sealing systems is available through Dupont Flooring Systems. They have locations across the country. The commercial flooring job I recently investigated would have cost $7-8/sf to rip up existing VCT, clean the glue off, seal the concrete, and install new VCT.
Good luck. Pinpointing the source of the moisture can be a difficult task.
Thanks for the iinfo. Slab is 50+ years old and we found an old grade stake void that barely broke the surface. I guess it rotted long ago. I doubt there was any vapor barrier or stone under the slab. It sounds like we need to find source before any slab tests.
I've been doing some research on products.
Koester makes a number of products that sound promising.
Consumer Reports had an article in June 2002 where they raved about products from UGL.
Good luck.
OA
I have a similar problem, although not as much moisture as it sounds like you might have. My brother is an architect and came across a product from Mapei (maker of quality grout and mortar products for concrete floors). They have a product called Planiseal MRB that is a moisture reduction barrier coating that promises to knock down the moisture vapor transmission in a concrete floor by 75%, guaranteed. It resembles a whitish paint, and you canroller-brush in on the floor yourself. The floor has to be clean (no beading of water from oil, etc). I plan to use it as part of my solution. Here's the link:
http://www.mapei.com
This will help with the symptoms, but not a cure for the disease. Lots of issues to consider including exterior drainage patterns, slope of terrain around house, existence of footer drains, and others to get to the root cause of the moisture.
I checked it out and I think that might do the trick, thanks