Corner shower grouting
 

We had a tile corner shower installed in July of 2010. The grout corners continue to crack. We have re-grouted 3 times, but the grout continues to crack. We do not know what to do, short of tearing the shower out and starting again. A new wood frame was installed along with new wall board and all new tile.

Use grout caulking in that corner they should have the same color as the grout you used, it's flexible & it look exactly as your grout

You can also use a 100% silicone caulking. I think it grabs better and has greater flexibility then the grout caulks. Main issue is the limited color choices.
Ron

Always happens unless you use a flexible additive mixed with the grout.

Inside corners and material transitions should always have a flexible sealant "movement" joint.

As suggested, I would lean toward a 100% silicone sealant that is color matched to your grout. There are a few companies who make acrylic color matching caulks but these do not hold up to the heat in a shower.

Rather than simply going over the cracked grout with caulk, I highly recommend you scrape the grout out of the corner completely first. You'll have a much better looking, longer lasting joint that way.

especially if one (or more) of your walls is an exterior wall.

Thank you for all of the information. Does the caulk need to be pushed back into the corner to fill up all the space like the grout was?

Yes a good caulk job will fill the void and not just lie on the surface.

Mark

what kind of grout are you using?
 

I am doing the same job in my shower right now and about to start the tile work. was wondering if you are using an epoxy mix grout or a regular grout. Does this make a difference? We plan to use the epoxy mix.

You will still want to silicone caulk the corner.

We used a polymer sand grout but it cracked in the corners. We are going to re-do the corner with a silicone caulk

Epoxy is stronger that regular grout. And it doesn't stain easily. But it is very hard to work with and for me does not worth it. I prefer to caulk and seal everything. And take care of it regulary.