mildew wall repair

[jonmar]

Mildew in cabinet under bathroom sink in basement. This is on interior wall which corners with exterior wall. There is a closet on opposite side of the wall that has the mildew but the closet wall (which is paneling) is o.k., no sign of dampness, etc. The mildewed wall, which I've been cleaning with clorox + detergent, is starting to crack and crumble from the dampness. I'm at wits end on whether to call a plumber to see if the problem is between the walls or if dampness is coming from exterior wall. With all the rain we've had in PA this year it could very well be coming from the outside. I don't want to call a plumber if I don't have to. The other question is how to repair wall (I assume it's plaster). P.S. We've checked the slope at foundation and also checked gutters but they did overflow several times in spring. How long would foundation take to dry out? Help! Thanks.

[LazyPup]

The problem may not be water coming through the wall at all. It may be caused by a lack of ventilation.

As the air gets in between the cabinet and the wall it remains static, and is cooled by direct contact with the basement wall, which in turn causes the humidity in the air to condensate on the wall.

[jonmar]

I have been running a dehumidifier to try to help this problem + been letting shower fan on longer than usual to help remove moisture from that factor. Now that it's approaching winter we will have heater running with humidifier. Does it make sense to keep running the dehumifier that the same time?