How to Remove Mold from Caulk

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  • Transcript

    LESLIE: Shelly in California listens to us on KVML and also has mold in the bathroom.

    Shelly, how can we help?

    SHELLY: Hi. I recaulk my bath about every year, every two years because it always forms a mold underneath the clear, silicone caulk. And the last time I did it, I called the company whose product I was using and asked them how I could ensure that it would not happen again and they said just make sure it’s dry; maybe put alcohol, bleach on it so you make sure you kill everything …

    TOM: Right.

    SHELLY: … and recaulk it. And within about two months, I got that black mildew under the caulk.

    LESLIE: Well, it sounds like you’re doing everything right but there is one additional step you can take. They actually make caulk with a mildicide in it. Is that correct, Tom?

    TOM: Yeah, it’s called Microban and DAP has a caulk with that as an additive. And what I would do, Shelly, is I would recaulk once again – now you get rid of the old caulk and if you have any trouble getting that off, there’s also caulk softener products that will soften up old caulk – wipe it down again with the bleach and the water solution so you get away any mold that’s there. There’s an additional step that will make sure that the caulk doesn’t pull out quite as quickly and that is to fill the bathtub up with water because it kind of weights it down.

    SHELLY: I heard about that last week. It’s a cast iron bathtub.

    TOM: Oh, better yet. Yeah. Fill it …

    SHELLY: I don’t think – it doesn’t fall out.

    TOM: No, but – oh, it doesn’t fall out at all?

    SHELLY: No, it stays in fine.

    TOM: OK.

    SHELLY: It’s flexible, it’s wonderful. It’s silicone. I really like it.

    TOM: OK.

    SHELLY: And I heard that show last time I was listening and that’s kind of why I called you because “Well, what about the mold underneath?” (chuckles)

    TOM: Well, what happens with silicone is it has sort of the greenhouse effect. If the – sometimes you seal in the mold and then the sun gets through there and it sort of bakes it; the light gets in there and it bakes it and makes it grow even quicker. That’s why they started adding mildicides to caulk. So I would remove the silicone. I would not use the silicone and I would put in a latex caulk that has a mildicide built into it. I’ve done that in my bathroom and it stayed bright for a long, long time.

    SHELLY: Great. And is there a particular brand?

    TOM: DAP makes one that has the Microban in it – DAP, D-A-P – and I know that Red Devil has one with an antimicrobial additive as well. But make sure you choose one that has the additive so that it doesn’t grow anymore mold.

    SHELLY: That sounds good. And latex, I’m surprised. Is it clear?

    TOM: No, it’s white or – it’s usually white but I – you know, I don’t know if it comes in clear. I presume that it doesn’t. It’s probably going to be white or tan.

    SHELLY: Because my grout is green.

    TOM: Your grout is green? What color is your tub?

    SHELLY: White.

    TOM: Well, use a white caulk then.


    TOM: Alright, Shelly?

    SHELLY: I’ll check it out. Thank you very much.

    TOM: Alright. You’re very welcome. Thanks so much for calling us at 1-888-MONEY-PIT.

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