A friend rebuilt a shower for us. I'm trying to figure out what to do with a problem. There are a number of places where the grout has already pitted, cracked, or just isn't enough in spots to make the walls waterproof. Is there a good product to use on one wall that will seal it but not make that wall look different from the others?

Has the grout ever been sealed?
It needs sealed periodically.
Tile in of itself is NOT waterproof.
If the grout is cracking you might have to remove it and re-grout it.

Do you have the original bag of grout? Often there is some left after a job. Do you know the manufacturer and color? Otherwise getting it to match just right will be very tough.

Now, why is it cracking? How big are the grout joints? What kind of grout was used? Sanded, non-sanded or some kind of epoxy grout?

Is the wall solid? If the wall has some flex to it it will cause the grout to crack. Is the shower pan solid? Is it cracking throughout the wall or at the corners? Just one wall?

He left some seams so wide that I think cracking is inevitable without rebuilding the whole wall.... which I'd rather not do if there is a reasonable made-do solution

Grout can be stained after installation to match a wall that is different.

quote:

Originally posted by ChuckFinley:
He left some seams so wide that I think cracking is inevitable without rebuilding the whole wall.... which I'd rather not do if there is a reasonable made-do solution

So what kind of grout? Standard non-sanded is for smaller grout lines. Sanded is for thicker grout lines.

Your best bet besides redoing the tile is to go to a real tile shop, not HD/Lowes and talk to them. There are some epoxy grouts that will work better than standard grout for your application.

Understand depending on how it was built this may not help.

Good luck.

I've use caulking to repair issues with grout. You should be able to find the same color as the existing grout and find the type that has a sandy grit so it looks exactly like grout. Pretty easy to work with once you get the hang of it. If you screw up, just was it off before it dries and try again.

If your grout lines are "huge" as you noted, nothing you do is going to survive for very long. After doing some tile jobs in the past, I'll never again do grout lines bigger than 1/16". The bigger question to me about your shower would be whether your neighbor properly waterproofed the walls and floor of the shower prior to installing the tile. If he didn't, you've got much bigger problems than cracking grout.

There is a sanded caulk made for caulking grout lines that comes in a caulking gun cartridge. It works really well and does a better job in situations where you have grout lines that are too big. The ones I experienced were only along the edge (tub to tile) and corners...…. I wouldn't do an entire tile wall with it, but if you have a grout line or two or three it would work well as a repair.

Here they are at Lowe's
https://www.lowes.com/search?searchTerm=grout+caulk

Thanks for the very valuable inputs!
The overall waterproofing is fine. That I saw before he did it. The rest of this is very unfortunate, but I'll explore the great ideas given.

Thanks SF!

A lot of work but I'd scrape it out and regrout with Epoxy Grout or Polyurethane Grout - both are two part mixtures and are the only ones I use anymore.