10 year old Ceramic Tile floor popping up..Help!
I need some help from a Floor pro if possible. I have a customer who has a 10 Year old ceramic tile floor installed over concrete in a semi basement. The tiles are 12x12 and have been perfect for the past 9 1/2 years. In the last few month they noticed the tiles heaving up about a 1/2 inch or so. The tiles are NOT individually lifting up, but whole areas of the floor. The tiles are all still held together perfectly with the grout. No cracks at all.
I chisled away the grout lines on one tile and the thinset was firmly attached to the bottom of the tile, but was cleanly pulled up from the floor. There was evidence of old black mastic on the back of the tile.
My questions are as follows:
1- Why did it take so long for the tile to loosen its grip?
2- Should the installer had laid the floor over the previous VCT floor adhesive directly?
3- If a new floor is installed over the concrete again, how is the old VCT adhesive removed?
4- Would moisture from recent rains have caused this? The cement appeared dry under the removed tile.