Best fix for loose floor tiles

Tips on removing, reapplying adhesive

By Bill & Kevin Burnett
Inman News

Q: I live in a San Francisco Victorian that has had the rear porch enclosed and later turned into a room. The room is attached to the kitchen, and the floor is finished in terra cotta tiles. The supports holding the addition up have been settling over the years.

We purchased the house six years ago with the intent of tearing down the porch and building an addition. We are in the planning stages, but construction won't start until some time in the summer.

Because the pilings are settling, there is some warping in the floor, which has caused some tiles to come loose. Since they will eventually go, I don't want to take the time to do the appropriate repair. I just want the tiles to stop rocking.

Is there a product you recommend that will be an adhesive and also a filler? Do you have any suggestions otherwise?

A: Sometimes the best way to do a quick fix is to do it the right way. The temporary repair we recommend is no more work than trying to cobble something together. With luck, the substructure of the porch isn't moving so much that the repair won't last until the porch makes its trip to the landfill. But there are no guarantees.

We're very familiar with screened sleeping porches that were often appended to Victorian-era houses. There was no glass in the windows, which allowed air to flow through during the summer. We're always curious about the utility of these rooms, considering the temperate summertime climate in the San Francisco Bay Area.

Because these porches were not designed for heavy use, the framing was often substandard. We're guessing inferior framing, and perhaps undersized foundation support, is the reason the porch is settling, the floor is warping and the tile is failing. The quick fix to repair the loose tiles is also the fix we recommend to repair a loose tile on a sound floor. You'll need a box or bag of thin-set mortar, a notched tile trowel, a bottle of latex thin-set additive and a small box of grout. All these are available at hardware stores and home centers and should cost about $30.

First, carefully pry up the offending tiles and scrape any residual mortar or mastic and grout from the void so the sub-floor is exposed. Also remove any mortar or mastic that is stuck to the back of the tile. If the tile is set with mortar, a brushing with a stiff wire brush will do the job. If it was set with mastic, soften the mastic with lacquer thinner or acetone and use a putty knife to remove most of the mastic. When working with lacquer thinner or acetone, make sure you are in a well- ventilated area. Next, vacuum any residual mortar, sand or grout from the hole.

To reinstall the tile, mix the thin-set mortar with latex additive to a consistency a little looser than toothpaste. Spread the mixture on the back of the tile, using the notched trowel to make ridges. Apply a layer of mortar to the sub-floor in the same manner. Install the tile and wiggle it so that a good bond between the tile and the sub-floor is established.

Some of the thin-set will seep out around the tile. Remove it. The handle end of a toothbrush works pretty well for this. Let the repair dry overnight.

The next day, grout the repair. If the existing grout is gray, the thin-set mortar can do double duty as grout. Let the repair set up for a couple of days before anyone walks on it.