Concrete Block Basement: How to Remove and Prevent Mineral Salt Deposits
LESLIE: Nicki in Indiana is dealing with some moisture in the basement. Tell us what’s going on.
NICKI: Well, our house is 21 years old. We have a concrete block wall basement. When we built, we did all the draining and all the things we were supposed to do on the outside. We sealed the concrete block on the inside, painted the walls. And after 20 years, we started having mildew and mold.
NICKI: We do run a dehumidifier down here. What do you suggest we do?
TOM: Well, when you say you have mildew and mold, are these walls still concrete block or do you have – are they covered with wood or anything of that nature?
NICKI: No, we did not, we did not.
TOM: Alright, so what you’re seeing is like – are you seeing like white-gray, crusty stuff come through the wall?
TOM: Yeah, it’s not mildew. It’s not mildew and it’s not mold. What you’re seeing are mineral salt deposits.
NICKI: Well now, it does turn black, dark, and then I was finding mildew on some of the furniture; some of the cabinets.
TOM: (overlapping voices) Yeah. OK, well that’s a different issue. But you’re not going to get mold on those walls because they’re not – there’s no organic material there for the mold to eat. Typically, what you’re having there is mineral salt deposits and you can prove this to yourself. If you take white vinegar and spray it on there, you’ll find that it usually disappears.
TOM: But the reason this is happening is because you have a moisture problem outside and I think you should address the drainage. And the fact that, you know, it’s fine except for now after 20 years means something broke down; so let’s go through the basics. Make sure your gutters are clean and free-flowing, make sure the downspouts are extended four to six feet away from the house and make sure the soil slopes away from the house a drop of six inches over four feet.
NICKI: (overlapping voices) OK.
TOM: Those three things will stop almost all wet basement problems.