Irregular grout

I have a 4 year old house. In the master shower the grout is expanding. It is sharp and cant be scratched off. It seems it should not be used in a shower and I am not sure what to do about it. If I have a little more information I can go to the builder to repair. The same shower the grout under the shower head is gone. The builder says this is not leaking below the tile. This grout will not come clean no matter what I do. That doesn't make sense to me. Any ideas?

4 years would be beyond the normal warranty period for a house, but I cannot imagine HOW grout can "expand". But if it is expanding, and not pulling the tile off the wall, then it cannot have adhered to the tile so it MUST be leaking, however slightly.

We would love some photos. The concept of grout, or even caulking, "expaning" is hard to grasp. Is it possible the tile itself is moving?

I know of no grout which would NOT be suitable for showers. Grout is a portland product, is NOT waterproof , which is why the substrate must be waterproof, and should never "expand".

If the tile was installed with a mastic, the wall behind the tile might be getting wet and expanding, pushing the grout out. Still, hard to image what's going on. You might check with www.johnbridge.com for some other thoughts.

Thanks everyone. I will try to load photos. The workmanship is terrible so I am afraid the water below pushing the grout out might be viable. Also I can't get this grout clean no matter whatbi try, bleach, CLR, tile and tub, grout brush, etc. Rediculous

Grout is mostly cement with some colorants in it, and maybe some sand. Once cured, it doesn't expand. Stuff behind it might, and break the bond, but it's more likely that the tile is moving, and you're just seeing the weakest point, the grout line, breaking. If the tile was installed on say drywall, or greenboard, that could be decomposing and creating problems.

I have not heard of grout expanding before and your job seams a little off the beaten track.

Do you know what type of grout was used?

Is it happening everywhere?

Is there any evidence of drywall cracks near this shower? You could have settling issues with your home and the wall (if it's just one) could be crowning and forcing the grout out.

Some framing details and a closer inspection is needed. Try contacting the NTCA (National Tile Contractors Association) for a reliable tile setter to inspect the work and if you are noticing drywall cracking in your home find out the structural engineer's name on your project and get him down there sooner than later.

Good luck with this.

It may be that the shower is leaking below the shower head and this has caused the wall studs to swell and push against the tile assembly.

If you can cut into this wall from the back side you can determine this quickly and have at least some piece of mind knowing the problem.

JW