How to Get Rid of Mold on Caulking

LESLIE: We’ve got Sue from New York who’s dealing with some moldy caulking. Tell us what’s going on with the mold on caulking.

SUE: I have a bathroom that has mold all over the caulking.

TOM: OK.

SUE: I’ve tried bleach and water but I was wondering if there’s something else I can do to get rid of the mold on the caulking.

TOM: Well, sometimes the mold on caulking really takes hold, literally, and it grows into it and it discolors the caulk. So if you’ve cleaned it in those traditional ways, probably not going to come out. So I would recommend that you recaulk the bathroom tub. And let me tell you how to do that successfully.

First of all, you can purchase a product that’s called a “caulk softener.” It’s kind of like a paint softener or a paint stripper but it softens the caulk and makes it easy to get all of the old stuff out of the tub and the joint between the tub and the tile wall and so on. Then once you’ve got it all out of there and all cleaned up and dried out – and I like to wipe the wall with a bleach-and-water solution in between, just to make sure we’re killing any mold spores that are left behind.

The next thing that you’re going to do for mold on caulking, Sue, is fill the tub with water. And you’re doing that because you’re going to kind of weight it down. And then once it’s filled, you can go ahead and recaulk that seam.

Now, the caulk that you use, make sure you use one that has a mildicide in it. So if you use a kitchen-and-bath caulk, it probably is going to have a mildicide. I know that the DAP products have an additive called Microban; I’m sure there’s others, as well. And then once that caulk dries, then you let the water out of the tub, because then it comes back up and compresses the caulk. And when you step in to take a shower, it doesn’t cause as much stress to that caulk seam between the tub and the wall and it stays in place.

So, again, if you’ve already cleaned it, it’s probably a foregone conclusion that you’re not going to be able to get that mold out of the old caulk. I would just replace it. It’s not a hard job and it’ll look really nice when you’re done, OK?

SUE: Very good. Thank you very much. I really appreciate all your help.

TOM: Thanks so much for calling us at 888-MONEY-PIT.