We recently had our friend who is a contractor put in a walk-in shower for us. Now, i have noticed cracks in the grout between the tile floor and tile shower wall, i know there is a water-proof layer behind the wall, but can there still be water damage? should we re-do the shower?

if there is cracking, the tile is moving. there are certainly going to be leaks.

the 90-degree corners are always going to crack, and all the grout should be dug out with a removal tool, and replaced with silicone caulk at those joins.

ideally you should scare up an inspection camera (as low as $65 at harbor freight with the 20% coupons all over the Sunday papers), poke a nickel-sized hole in the opposite side of the wall, and look for water and issues. but if that is the only fault, a quick repair will probably save your bacon.

This message has been edited. Last edited by: swschrad,

I am going to disagree with the above. While the cracking does indicate some movement or expansion/contraction going on, those cracks are not going to cause leaks.

Tile is not waterproof. Grout is not waterproof. Both will allow moisture to pass through. Showers rely on a waterproof liner in a pan that extends up on the walls at least 6". Walls are lined behind a waterproof backerboard and that liner will drain into the pan in front of the pan liner. Because of this, grout cracks, especially where yours are will not cause a leak, but they do need to be fixed.

The cause could be something serious like improper or weak framing allowing the shower base to move. Or, it could be typical expansion cracks - especially if the shower wall is on an exterior wall. Take cold tile and blast it with hot water and something is gonna move.

It the shower was built correctly with the proper liners and it's not a bad framing problem, then you can fill the crack with a grout caulk. This will match the color and texture of the grout yet will still allow some expansion and contraction.

Now, it you can determine that the shower was not correctly constructed, then a shower rebuild is in your future.