Hi
In one part of my old house in El Centro, I have a white substance that penetrates the wall paint. Has anyone ever come across a situation like this and is there solution to this problem?

John

The white powder that you are referring to is called efflorescence. It consists of mineral deposits that are left behind when water evaporates.It is very common to have efflorescence on basement walls and floors. Concrete acts like a wick. If there is dampness on the other side of the concrete, the concrete will draw the water to the inside of the house where it can evaporate. When the water evaporates, the minerals, that were contained in the water, crystallize and create the white powder. Anything you do to the interior of the wall will not stop the efflorescence from forming. It will form below the paint and cause the paint to flake off the wall. Your best bet is to reduce the moisture on the outside of your house with good eavestroughs and grading. This will likely reduce it but it may not eliminate it. Oddly enough, the dryer your basement, the more efflorescence you get, because the wall acts as a wick. The dryer the inside surface, the more moisture gets pulled through the wall.