Tuesday, March 15, 2011

Can I stain and seal a basement floor with moisture problems?

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Q. -  hello, i have an interest in acid staining my basement floor but have some questions and concerns. i assumed i had a relatively dry basement. i moisture tested by taping plastic and saw no evidence of moisture. i installed a laminate floor and about 2 months later i had buckling. i assumed it was due to the water table with this harsh winter and then someone told me that i was probably getting moisture from the slab. i never saw any slick spots or water in the past because it was probably evaporating and drying as soon as it reached the surface. when i placed the laminate and moisture underlayment i created a greenhouse affect and trapped the moisture and that caused the buckling. i'm not sure if that sounds like what happened, but it does seem logical. here in lies my question. i'm led to believe that if i seal the floor or paint it, i will bubble since i'm not allowing the moisture to evaporate like it needs to. any other flooring surface will be subject to moisture collection i assume....carpet, tile, laminate so those don't appear to be viable options. my question is, if i acid stain and use a water soluble sealer, will that allow a small amount of moisture to evaporate and not cause future problems? what would you suggest in my case? i never had any visible moisture issues until i covered my basement floor. i appreciate your opinions and thank you. tom patavino
Hello Tom,
A. -  The acid stain will be fine as it works by creating a permanent change in the concrete's surface color, therefore stain does not sit on the surface like paints.
   The sealer however, does sit on the surface. Pretty much most all sealers will close off the surface and then any moisture wicking up through the concrete will be stopped by the sealer which will cause the sealer to eventually lose its bond and start to flake off. The exception is the Concrete Camouflage brand: Clear Shield Advanced formula water base sealer. Because of it being a pure acrylic and not an acrylic mix as most sealers are, Clear Shield Advanced will allow a certain amount of moisture to wick through the sealer and evaporate. A major amount of moisture may not be passable but a minor to moderate amount of moisture wicking is part of the intended design. As you have described your slab it sound to me like your floor is a perfect candidate for staining and sealing with Concrete Camouflage products. At least it's worth the try.
   You will want to be sure that you do not wax it. The wax would seal off the floor and prevent the moisture wicking and escaping that you seek. Unfortunately that means that rather than using the wax as the intended sacrificial coat, and only having to maintain the wax, you will have to re-seal the floor every few years +/-.