We installed ceramic tile in my moms house. She has a concrete foundation which has a seam running through the dining room. We installed the tile so that the grout joint ran along the seam in the concrete. It has been installed for a few months. Yesterday the entire joint popped up. None of the tile broke, it just buckled up all along the concrete seam. Any suggestions on why this may have happened and what we can do to fix it?

Amanda,

What do you mean by "the entire joint popped up"? Are the tile tile stuck well? Did you test them by tapping them? What did you put in that joint? Did you leave an expansion joint around the perimeter of the room? How big is the room? Does it get wet more than the average kitchen? Does the sun beat on the floor much of the day? Specifically what tile did you install and with what, name names.

Start with those answers.

Jaz

The tile are completely popped up, two rows, from wall to wall where the two pieces of concrete foundation come together.

Nothing was put into the concrete joint as it is an expansion joint.

We did run mesh tape over the joint before laying the tile. The tile stuck to this mesh tape when it popped loose and basically made a tent where the tiles came off the floor. That's what I mean when I say that the tiles buckled. It wasn't like we walked on them and they felt loose. There was a loud pop and when she went to see what it was saw this area that was buckled up.

There is expansion all around the room. The dining room is large, where the tile popped is probably 18 feet across.

It does not get wet at all and the sun does not hit the room directly at all due to a covered porch.

I cannot tell you the name of the tile...it's ceramic tile we got from Lowes, 12x12. We installed it with thin set mortar that we mixed. No other tiles in the room are loose at all. Only along this joint in the floor.

Thanks
Amanda

Typically, that joint should not have been filled with grout. A color-matched grout caulk would have been in order there. With caulk, then contraction between the two sections of the slab would have little to no effect.

With grout, as the sections contract, pressure builds up on that grout joint and with no relief, something has to give. In most cases, like yours, the bond between the tile and the slab is the weakest point, hence the tenting of the tile.

Kman is right. If you grouted that line over the expansion joint that is the source of your problem. Scrape the tile clean and re-install with a very good quality thinset. Then caulk that grout line. Before you re install the tile clean out the joint in the concrete with a grinder and diamond wheel and fill it with backer rod (a soft foam strip)

I should add to be very careful when grinding. You need to maintain a firm two hand grip on the grinder to avoid kickback, wear eye protection and have a second person on dust collection with a shop vac.