House Foundation Problems
I decided to replace my carpet and when I pulled up the old carpet, the concrete was damp and I noticed a white power spread over the surface. What is going on with my foundation and is there anything that can done about it?
Joe Crimmons
Barker, Texas
Joe it is obvious by what you are telling me that moisture is coming up through your slab. Without seeing it, I would say the white power is most likely what is called “efflorescence” and it is generally a sign of alkali coming out of the concrete. Efflorescence is caused when you have moisture mixing with soluble salts and other water dispersive materials and surfacing to your finished concrete and leaving a white substance. Also low temperatures, moist conditions, condensation, rain, dew, and excessive water being added to the surface of fresh concrete to assist troweling can cause this to happen.
Contact a professional in your area
My suggestion is to contact someone in your local area to give you a professional assessment of your problem. If you chose to go on line, be sure you find information that would be pertinent to your city or county. What has been successful in many parts of the country, are sodium silicate sealers. Sodium silicate is used in a water-based mixture to seal the basement walls and floors, and it penetrates up to 4” into the substrate. After penetrating, the sodium silicate reacts with the free lime content of the concrete and you should be good to go.
What is happening with this product is that it is reacting with the sodium silicate and free lime-producing solid crystalline structures that fill the microscopic cracks and pores of the substrate.
Many products on the market are designed for leveling only. You need to find a product that will cure and seal your slab prior to adding a leveling compound. I would suggest you complete this process prior to laying new carpet. It will guess that your house has a musty, mildew odor and that is because over a period of time it is possible for your carpet to gain enough moisture to cause mildew in it. You certainly don’t want to repeat this process with your new carpet.
Category: Reader Question
