Killing Mold on Drywall

Q - We own a 61 year old home with a finished basement. Our problem is that there is a mold or fungus which has infected the plaster on the northern wall. We are taking steps to apply as much moisture protection as possible (sump pump, dehumidifier, moving air). We're planning a partial remodel on the northern side of the house and will excavate and coat the below grade cement wall on the exterior.

In the meantime, however, we have been unable to eliminate the mold and fungus that deteriorates the finished plaster and paint on the wall. Bleach does a good job of stopping the mold/fungus for a short period. Unfortunately, the bleach has not eliminated/destroyed the problem.

Can you recommend a product and/or a procedure that might provide better results?

Craig

A - Assuming that the drywall is worth saving, i.e.,. it is not falling apart from water damage, here are a few methods for dealing with the mold:

Bleach, etc. will not penetrate the drywall and will only kill the mold spores on the surface. The remaining spores can remain dormant inside the drywall until the next time when enough moisture exists for a "bloom". So, in addition to moisture control, a good priming with a pigmented shellac will block the mold spores into the drywall and reduce the likelihood of future damage.

There are a few companies around who use high concentrations of ozone to kill mold spores. This appears to be a good method of killing the spores inside the wall material and cavities. I only have a limited amount of experience with this method, and would suggest that you find out if someone in your area does this work, and knows how to do the work correctly. (This type of ozone treatment is used to kill mold in grain and mold infestation in modular homes).

You mentioned several secondary ways to deal with water entry into the basement. Don't forget that the primary way to reduce basement moisture is with a good gutter-downspout-drain system and with proper grading around the perimeter of the house.