White Fuzz on Concrete Floor: How to Clean

LESLIE: Blair in North Dakota, you’ve got The Money Pit. What can we help you with today?

BLAIR: Yes. Say, on one of your previous shows, I heard that you got – I got this white mold or fuzz that grows on the cement floor in the basement.

TOM: OK.

BLAIR: And I have a – it’s a finished basement. And the thing is, I heard that you have vinegar and water to clean it up.

TOM: Yeah and let me tell you, you’re calling it mold but I don’t think it’s mold; I think it’s mineral-salt deposits. Because mold doesn’t grow on concrete; mold needs an organic material to make it grow. But typically, what happens is if you get high water, moisture, humidity, you will get – some of that water will evaporate off and leave its salts behind. So you end up getting this sort of white, grayish crusty stuff that will form on block walls and also concrete floors.

LESLIE: Yeah. And you’ll even see it around faucets, like in your kitchen if water sort of pools there. It’s just the mineral.

TOM: Yeah, that’s right. And the reason that vinegar-and-water makes it go away is because the vinegar melts the salts.

LESLIE: More vinegar than water, though.

TOM: Yes.

LESLIE: And white vinegar.

BLAIR: Is there anything there that you can keep it from coming back?

LESLIE: Maintain your water and moisture on the outside of your house.

TOM: Yeah. Improve your drainage and your gutters at the outside of the house; that’s generally what causes it. If your gutters are clogged or not discharging well enough away from the foundation, if your soil is not sloping away from the walls, those two things cause this problem on a very frequent basis.

BLAIR: Yeah, we’ve got a sump pump in the basement and we’re kind of in a …

TOM: Does it go off when you get heavy rain?

BLAIR: No, not really.

TOM: Yeah. Does it go off other times?

BLAIR: Well, yeah. We got – you know, it kind of – how do you say it – water troubles here in North Dakota so …

TOM: Well, if your water troubles get worse after a heavy rain, then it’s sourcing at the drainage conditions at the foundation perimeter. I would start with those. Even if you did have a high water table, it’s very likely that poor drainage conditions at the foundation perimeter are the number-one cause of this.

BLAIR: OK. Thank you.