Published on December 24th, 2013 | by Henri0
Concrete scaling on basement floor
Q. I need help. I have had my house from new. After four years, I used a good industrial oil-based floor paint on my cement basement floor. It was down for 20 years. Then I used water-based paint and it lasted 20 years. I wanted to get back to oil-based paint.I used as heavy-duty floor sander and took off much of the old paint.
Now the problem. In a few spots on the floor, by the cinderblock wall, the cement is scaling. It bubbles up; I scrape it and a white powder comes up. What can I put on it to stop the white powder from coming back and to make the paint stick to the floor?
A. By the cement scaling, do you mean that it is breaking up or simply that the white powder is developing? The white powder is undoubtedly efflorescence. Moisture is dissolving the salts in the concrete and bringing them up. The moisture then evaporates, leaving the salts behind. It sounds to me that after 44 years you are suddenly having a mild moisture problem at the base of the walls — just enough to cause this new problem.
Check the grade around the house to see if there have been any changes that lead the water from the roof or gutters to pool against the foundation. If you find any anomalies, take care of them, and see if that solves your problem.by