Remove Moldy Caulk and Tile Grout
LESLIE: Tim in Alabama is calling in with a mold question. What can we do for today?
TIM: Yeah, hi. What I’m currently experiencing is in my bathroom area we have a marble shower area and the caulking has become overrun with mold. And directly when you step out of the shower, on the tile, the grout – where some of the water has dripped from the shower door – looks like mold is starting to try to set up in some of the grout there.
TIM: My question is what I have understood you’re supposed to do is just cut it out and recaulk it but I’m not sure if there’s any prep work that needs to be done prior to putting new caulking in and what do you do about the grout?
TOM: OK, the grout that’s – first of all, the caulk that’s down there now, is it clear caulk or is it …?
TIM: No, it is a color to match the tile.
TOM: (overlapping voices) It’s like a white?
TOM: Ah, OK. Well, here’s what you need to do. The first thing you need to do is to remove the old caulk. There’s no way to clean it because what happens is the mold actually gets in it, it grows under it. I mean you can wipe it down. Yeah.
LESLIE: (overlapping voices) Gets through it, goes behind it.
TOM: You can wipe it down with bleach but if that doesn’t do it, you’re going to have to strip it out; so you can use a caulk softener for that. There is a very simple – [trying to think of a] (ph) paint stripper but it’s for caulk; it softens the caulk. And then there’s a plastic tool that you can use to scrape it out with, available at any home center or hardware store.
Next, the new caulk that you put down, you want to make sure that you use a caulk that has a mildicide in it. The most common one is called Microban and I know it’s available in DAP caulks. It may be available in others as well. But this Microban product is pretty darn good and it doesn’t let mildew grow into the caulk. Since you have a colored caulk, it might be something that’s fairly custom. You may not be able to reproduce that exactly. I would just go as close as possible and make sure it has Microban.
As far as the grout is concerned, you can, again, try to clean that. You want to use a grout stripper, not a grout cleaner. It’s a little more aggressive. But if you – if it gets so dirty and so mildewy and moldy that you really can’t clean it, then what you do is you scrape the old grout out and you use new grout and the grout also should have an additive in it. The Microban is available in grout, too, and the brand that carries that is called LATRICRETE – L-A-T-R-I-C-R-E-T-E – so you can actually replace the grout with a grout that has Microban inside of it and that should stop the mold problem.
The other thing, though, is to make sure you manage the moisture inside that bathroom; that will actually help as well. So make sure you have a good, powerful vent fan that runs for at least 20 minutes.
LESLIE: And you use it.
TOM: Yep. Runs for at least 20 minutes after you’re done.
LESLIE: And you know what? Tim, while you’re at it with the caulking, when you take out the old caulk, you want to mix up a solution of bleach and water and go pretty heavy on the bleach and spray it where you’ve taken out all of that grout just so that any mold spores that may have gotten behind it – I’m sorry, the caulk – so any mold spores that may have gotten behind it, you can kill those then let that area dry out very well and then apply the new caulk in there. This way, if there’s anything back there, it’s not going to grow again on the new.
TIM: Ah, will do. Thank you very much. Appreciate your help.
TOM: (overlapping voices) You’re very welcome. Thanks so much for calling us at 1-888-MONEY-PIT.