Cracked Kitchen Tile Repair, Oakland Hills, September, 2026

This cracked kitchen floor in the Oakland Hills was trickier than it looked.

The cause showed itself as soon as the cracked tiles came up. It looked like mastic, or some kind of unusual mortar, had been used to set them. When tile goes down properly, the mortar is spread with a notched trowel. Here it was a quarter-inch notch, which leaves ridges with gaps between them. When the tile is pressed in, those ridges collapse into the gaps, spreading the mortar into a solid, even bed under the whole tile. That’s what levels the tile and makes it stable.

Under these tiles, the ridges were completely pristine. They’d never collapsed, and they barely seemed to have touched the tile at all. That meant the tiles were sitting on narrow lines of adhesive with hollow space between them. Over the years, with people walking across the kitchen, the unsupported tiles flexed and cracked under the weight.

Getting the cracked tiles out took care too. Even broken, they couldn’t just be popped up: pry too hard, and the stress transfers to the tiles next to them, which can crack the good ones you’re trying to save. So we used an angle grinder with a continuous-rim diamond blade to cut along the long axis of the damaged tiles in the center of the kitchen, relieving them before lifting. Then I worked the pieces up with stone-working tools. Porcelain fragments are very sharp, sharper than glass. The way porcelain fractures, the edges tend to come out razor-like, so the cleanup takes care as well.

With the damaged tile out, the replacements went down in a full bed of polymer-modified mortar, this time with complete coverage so every tile is fully supported. We chose gray mortar so that if any came up through the joints, it would blend with the grout rather than stand out.

The mortar set overnight. The next day, we came back and grouted with a custom-mixed gray to match the existing grout, which had faded and lost some of its color over the years. Fresh grout in the original color would have made the repair stand out. Matching the weathered grout is what makes it disappear into the rest of the floor.