Tile Surface Mortar Removal, San Bruno, CA 2025

The title of this post is a bit of a paradox. There should never be mortar on the surface of a tile in the first place. Mortar goes behind the tile, bonding it to the backer. Grout goes between the tiles, as the final stage. When mortar ends up on the face of the tile, something has gone wrong.

In this San Bruno kitchen, quite a few things had. The original installer set the one-by-two-foot field tiles in mortar on the backer, which is correct, but then used mortar again in place of grout to fill the joints. Mortar isn’t made for that. It doesn’t pack, finish, or clean up like grout, and it left the joints splotchy and uneven. The installer also never used a haze remover or properly cleaned the tile afterward, so a film of mortar dried and bonded to the tile surface.

The tile itself was the wrong choice to begin with. The client had been sold a glossy tile for a kitchen floor. We don’t recommend gloss underfoot in any area that gets wet, because it gets very slippery. A floor tile should be matte or textured. Here, the gloss was buried under a dull haze anyway, and with uneven joints and at least one tile not sitting flush with its neighbors, the floor looked terrible.

Fixing it was a cleaning job, and a heavy one. We had to clean two things: the film on the face of every tile, and the mortar in the joints between them. We used a high-speed brushless power drill with special scrubber heads, and experimented with a variety of solvents and solutions to find what would break down the mortar film without damaging the tile’s surface. Then we worked through all 200 or so square feet, scrubbing tile by tile and finishing by hand where the drill couldn’t reach.

It was pretty heavy work, but the results were dramatic. The haze came off, the tile’s finish came back, and the floor finally looked like what the client had paid for.

The lesson for homeowners: when a new tile floor looks dull or filmy right after installation, it isn’t the tile, it’s the cleanup. Proper grout and a proper haze cleaning at the end of the job prevent all of this.