Grout cracking in shower - best way to repair?

Not an inspection question, this is just a problem in my house. The grout has cracked in several places in both the tiled showers in my house. Mainly in the corners of the shower walls.

There is a little movement in the foundation due to drainage issues that are being resolved, but the grout has been cracking in the past 6 months or so.

I’m planning on renovating the master shower/tile in the next year or so, so I just wanted a quick fix. I cleaned out the grout that was cracking in the corners of the shower and replaced it with silicone caulking. When I removed the grout it comes out pretty easy in places. Even flakes off if you scrape it with a fingernail in areas that aren’t cracked.

This crack is continuing down from the drywall (if you can see it) down through the grout on the second floor.

I haven’t done a lot of tile and grout work. Best way to repair?

Fiberglass shower pan.

Silicone is flexible so that should work.
They also make a tape like silicone that is wide enough to cover gaps.
Otherwise there are not to many alternatives that do not involve removing or covering the shower wall with a surround.

HEY John, I am a tile guy, in my other life. Corners are notorious for cracking unless they are caulked. That is unsanded grout and it has a tendency to flake out, usually can be removed easily with utility knife. You can silicone the corners(which sounds like what you have done) and regrout the rest. If you want to do more you could regrout with Laticrete Permacolor grout. Regrouting with caulk or silicone will take a long time and probably not worth it.

It could be a systemic problem with the grout itself. Grout that is not allowed to cure properly before being sealed (3 days min, even up to 7 days) or applied with too much water on the grout sponge will be weak and crack.

If you think it is a grout problem, remove the old grout, properly reapply the grout and seal it.

Throw water on the grout and see if it changes color to know if it is sealed.

Jim is right, tiled corners are notorious for cracking. Unless you have a waterproof membrane system behind the tile, it could turn into a problem.
Silicone it after you have removed the loose grout and regrouted fresh. Clear silicone or get a silicone match for the color. :slight_smile:

Great! Thanks for the replies - I guess I was on the right track after all with the silicone.

And yes the grout turns dark instantly when it gets wet. Is it too late to seal the grout that is already there? Built 2004.

looks like what I’ve got

Sell the house!! :p:roll::shock::twisted:

John you can reseal the grout any time. Most sealer manufacturers recommend sealing every few years. Make sure to follow directions on bottle, and have fun.

I’ve confidently used the sanded/unsanded tile caulk products at all corner and floor to wall joints… silicone, IMO, looks like Harry Homeowner crap.

The tile caulk products are desinged for these areas and shouldn’t give you as much trouble…

In a vanilla white unsanded install, maybe silicone looks OK, other than that, do it right

You can find some at big box stores like or DAL tile or your local Tile supply house.

Good luck

I agree Tim;

Any time that two areas of tile join each other in a 90-degree angle, particularly at horizontal planes, caulk needs to be inserted in place of grout as a joint filler. Simply purchase caulk which matches the color and texture of the grout to ensure a cohesive look.

For example, if white, sanded grout is used on the wall tile of a shower, white, sanded caulk should be used in the join between the shower walls and floor.

Tile caulk is an important part of nearly every wall tile, glass tile and shower tile application. Utilizing this material will help keep the tile job looking great for years to come, while protecting walls and floors from water damage.
Use tile caulk the next time a tile installation is undertaken and know that the tile job is built to last.

I have the same exact problem as Jim on a shower in a new construction home that I have lived in for 7 months.

Are you saying that after regrouting that corner, that a 100% silicone caulk should be applied afterwards?

Yes, (after it is dry, of course) you can use silicone or order a colored one to match the grout at a tile supplier. :slight_smile:

Corners should not be grouted at all. Use caulk at all corners and transitions like between the tub or shower and the tile wall. You can use regular caulking and match by color or if the gap between tiles is greater than 1/8 inch, use the sanded caulking.

The big box stores keep the specialized caulk in the tile department, not in the painting section. They carry a variety of colors of both regular and sanded caulk.

The best site for tile information is

Don’t re-grout. Clean out the corner joint and Use what Tim recommended.

I’ve used similar (different brand) many times, works and looks good. It’s flexible caulk (stays soft) that looks like grout, like Marcel said, you can color match with existing grout.

And what Steve explained while I was typing. :mrgreen:


OK Marcel…

Caulk or grout? :mrgreen:

I’d say better left alone, looks just great the way it is.
But might want to monitor daily for any activity. :wink: