Grout sealant to truly waterproof grout?


Old 08-16-18, 09:02 PM
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Question Grout sealant to truly waterproof grout?

I've used a couple different kinds of grout sealer in the past. I would consider it "better than nothing," and might even be fairly effective at resisting stain, mold and other problems. However, waterproof, it was certainly not. Pouring water on sealed grout still soaked in; just a bit more slowly than before.

I'm looking for a grout sealant which is either totally or at least nearly totally waterproof. Something more in line with what you would get if you smeared silicone caulk into the joints or painted it with weatherproof paint.

Alas, most grout sealants don't boast of being any more "waterproof" than any of the others, when I try to research for this quality.

I'm wondering if something like Thompson's Water Seal would work well for this purpose? Or is there a grout sealant with that level of waterproofing? Any recommendations?

For the record, I'm looking to seal 1/4" existing grout in a spare bathroom where the cats' litterbox is kept. On occasion they've been known to miss or kick litter out of the box and use the resulting piles. Keeping cat urine out of the grout is very important (making it easier to clean in the process). To this end, I'm looking for a less obtrusive sealant for the ceramic (porcelain?) tiles to make them easier to clean, as well...
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Old 08-16-18, 09:11 PM
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You would have better luck with different grout that actually has an additive that makes it moisture resistant, like Mapei grout maximizer.

Painting a sealer on the surface is just not as good.
Old 08-20-18, 02:21 AM
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XSleeper, thanks for the suggestion, but this is an existing floor with older grout. Ripping the old grout out and re-grouting is more work than I wish to put into this room. I just wish to apply a sealant which does a better job than what I've experienced in the past.

That said, what would you say is the most water-resistant grout you've used, even if it's not the "best" all-around? Since it's under a litter box, I don't need fancy, I just want something highly resistant to keep out any caustic liquids which might sit on the floor for a while.
Old 08-20-18, 09:47 AM
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Dont use Thompsons, it's really krappy stuff and not intended for grout.

My suggestion would be to just go visit a real tile store, not a big box store and see what they have/can get.
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