Tile tenting

[SharonW]

I have a 14 year old home with 12x12 ceramic tile and we are having some tenting issues. The original tile work was not great as there are cracks and missing pieces in some areas of the grout and we have some hollow sounding tiles (the hollow sounding tiles aren't tenting...yet). At first only one area started tenting and we thought it was due to a pet fountain we had on the floor. We thought maybe small amounts of water over time got under the tile. We moved the fountain and it seemed to still get a bit worse (over the course of 6 months) so not sure if that was the issue. Then we noticed on the other side of the wall from where the first problem was, more tiles were heaving upward and the grout was cracked. Both of the problem are a second tile away from the wall. The new area we noticed also has a pet feeding area, but the bowls are raised in a stand and are on a throw rug with a pad (I don't think any water has ever spilled there). To complicate the matter, the wall that separates the two spaces, we believe has plumbing for a wet bar (it's either there or under the slab, but neighbors and plumbers think it is in the wall). So far we have had several plumbers look at it, one said he thought we had a leak and thought we should replace the pipe for $2200 (only a 30 foot run) , and the other three plumbers felt there was no leak and thought is was a problem with the original tile installation. No water is visible under the few tiles that came all the way up and when water is turned off to the house, the meter has no movement. So, could it just be from poorly layed tile? I am concerned about replacing the floor and still having issues if there is a small leak we are missing. The rooms adjoin other rooms so we would be replacing about 1600+ square feet and I don't want to have problems again if I miss something now. The tile is on a slab foundation and we live in Las Vegas so there is very little humidity all year. Any opinions on if it is strictly a flooring issue or possibly a slow leak somewhere raising humidity in that area? Baseboards on the wall near both areas are fine, no sign of any water issues. Sorry this was so long!!

[Kman]

Welcome back, Sharon. Ten years is too long for you to not stop in and say hello.

If the tile was bonded well and had cured for the first month or so, water could get to it and it would not likely cause a problem. If it was poorly bonded and water got to it, especially in the first month, that could be an issue. But after 14 years my inclination is that water really has nothing to do with the problem you're having.

Typically, tenting is a result of there being no room for expansion within the tile installation. You mentioned there is 1600 feet of tile, and if it's contiguous throughout the house with no soft joints for expansion, that's an issue. Some of those grout joints, depending on their location, should have been left open and filled with a color-matched caulk.

If there are no perimeter joints left open for expansion, that's also a problem. There should be at least 1/4" of space left open between the tile and the walls or any vertical obstruction, such as a cabinet. That gap can be left open and covered by trim, or filled with caulk.

Without the space to expand, your tile has no room to go anywhere except up, which is what yours has done. The thinset will often shear off at the slab, leaving the slab very clean. You'll also see grout cracking, which is a sign of movement.

You can try to go through and remove loose and tented tiles and replace them, but I'm afraid that as you go along you'll find even more tiles coming loose. You may end up doing an entire room, or maybe more.

[Houston Remodeler]

What Kevin said.

Read pages 19-20

[Davy]

Hi Sharon. What Kevin said. Doesn't sound like a water problem. We've tiled the bottom of swimming pools without problems, a little water from the dog bowl shouldn't cause any problems.

I've seen several tented floors that started out in a large room with windows facing the south or west that allowed the sun to shine in on the tiles. The floor warms up, expands a little and breaks loose and tents.

[SharonW]

Thank you all so much for your input. Everything you said makes complete sense. I'm fairly certain they didn't leave expansion joints, and where the tile meets the baseboard they used grout not calk. Thank you again, you guys are the best!