OK to caulk over new caulk w/ different caulk [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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02-07-2011, 04:45 PM
i have had my new wall tiles over tub installed. I told guy i would seal corners and tub/tile edge cause i wanted to be sure to d it right with good stuff. After research and due to gfriend needing to take a shower i had to go with Polysealseam HIGH GLOSS white from HD. My tiles are matte white. I could not find anything that wasn't gloss finish, i guess cause everything has some silicone in it, like Polyseamseal does. Anyways, i found at a local tile shop today the Mapei "siliconized acrylic Unsanded Keracaulk that matches the same color of grout that i got. I bought a tube for $7.

Would it be OK to caulk over the Polyseamseal white gloss caulk job? It's a narrow line right now, so room to cover current seal. I just did it 4 days ago, so still clean and mildew(relatively) free. I don't want to pick out the new caulk...would make a mess and might look worse afterwards, i fear. Would the Mapie adhere to the Polyseamseal?

Should i leave well enough alone and not even use Mapei caulk over Polyseamseal or would it be ok? I live on pier and beam older house, so movement does occur in there, and have seen picks of Mapie separating from surfaces. The gloss white bugs me a bit, but i obviously would have been fine with it before i ran in to tube of Mapie matched sealer. Still, if it can look better i'm up for it.

Appreciate any help.

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Houston Remodeler
02-07-2011, 06:51 PM

I hate to be the one to tell you this but it pretty much doesn't matter. Any latex caulk you use will mold and turn a few shades of pink or black or both in a few months. 100% silicone is mold free. 100% silicone in both sanded and unsanded is available in over 140 grout matching colors from Color Rite.

02-07-2011, 07:33 PM
also, even though silicon caulk looks real shiny at first, it does dull down with age and lose its gloss.

And Paul is right about the caulk. If I were you I would scrape it out and put silicon in there.

02-07-2011, 11:19 PM
thanks guys.

what if i put silicone over the existing Polyseamseal? Like i said, it's a thin bead in most places and a narrow one in others. So even these silicone/latex "hybrids" will get moldy after a while?

Found a site with about 140 color rite colors. will colors have same name as color they are matching from, say, Mapie, as in Avalanche, which is what i used for grout color? Says their company site is under construction. Weird.

02-08-2011, 12:34 AM
Not a pro but all the advice and caulking guides I've seen online suggest that you should always remove all of the existing caulk and thoroughly clean and dry the surface before re-caulking otherwise the new caulk won't stick at all.

Everyone (who sounds like they know what they are doing) also suggests 100% silicon caulk for baths and showers. I made the mistake of buying one of those siliconized squeeze tubes to use for my tub (thinking it would be cheaper and easier to apply than with a gun) and now I need to start over as it got moldy within about a month and slowly started to peel away from the joint between tile and tub after getting wet. Needless to say, I was a little annoyed that they still label these things as bath or shower when most of them don't work well in places that see water at all.

02-08-2011, 08:00 AM
yup, you need to remove the existing caulk. It isn't that much work, a straight razor works best I find.

02-08-2011, 08:11 AM
i poked around the existing caulk last night and the stuff is freaking hard. Would be a beeatch to scrape out, i'm thinking. It's not like i would have to just get a piece peeled off and pull it out like a string, right? I would have to dig out every cm piece by piece? If i'm going to have to do that why not just wait til it gets molding, if in fact it does, and do it then?

I gotta say, i'm all worn out with this job. I didn't do it, but i stressed over it and managed it, to a small degree, and i'm just about petered out. The thought of scraping out 20 ft. of caulk doesn't appeal to me right now.

Why not wait til it starts to fail, if/when it does, and maybe scrape out caulk AND grout (the guy grouted corners first) and silicone the whole corner at that point?

Also, i thought the benefit of silicone was that it stuck to everything. Why wouldn't it stick to a joint with some caulk and tile? Like i said, i put a tiny bead in, so silicone would have quite a bit of tile to grab on to on both sides, along with the existing caulk.

02-08-2011, 08:16 AM
because moisture gets behind the tile through the grout, and your latex caulk will mold behind you silicon caulk.

And if you wait for it to fail you run the risk of mold starting to grow behind the caulk, which can be a pain to eliminate.

If you don't have the energy now that is fine, but I would tackle this project within the next few months, don't wait till problems start to emerge.