Step-by-step fix
Step 1: Make sure failed mortar is really the problem
- Tap the tile and the tiles around it with your knuckle or the handle of a tool.
- Check whether the tile sounds hollow, shifts underfoot, sits higher than nearby tiles, or has cracked grout around just that tile.
- Look for signs that the tile itself is intact and the floor below does not feel soft or bouncy.
- If the tile is already loose enough to lift, inspect the underside for old mortar that has let go or dried out in patches.
If it works: You have a loose or hollow tile with failed bond underneath, and replacing the floor tile mortar is a reasonable repair.
If it doesn’t: If the tile is solid but the grout is damaged, focus on grout repair instead. If several tiles are loose or the floor feels soft, the problem may be in the subfloor or underlayment.
Stop if:- The floor below the tile is soft, swollen, rotted, or crumbling.
- Multiple nearby tiles are loose, tented, or cracked from movement.
- The tile is part of a heated floor system and you are not sure where the heating elements run.
Step 2: Prep the area and remove the tile carefully
- Clear furniture and rugs from the area so you have room to work.
- Put on safety glasses and gloves.
- If grout is still locking the tile in place, scrape or chip it out around the tile edges to reduce the chance of cracking neighboring tiles.
- Use a putty knife or margin trowel to lift a loose tile. If it will not lift, work slowly with a chisel and hammer to free it without damaging the surrounding floor.
- Set the tile aside if it is still usable, and keep track of its orientation so it goes back the same way.
If it works: The tile is out and the surrounding tiles are still intact.
If it doesn’t: If the tile breaks during removal, use a matching replacement tile before resetting the area with new mortar.
Stop if:- Neighboring tiles start cracking or lifting as you remove the tile.
- You uncover widespread moisture, mold, or damaged underlayment under the tile.
Step 3: Remove all old mortar from the floor and tile
- Scrape the old mortar off the exposed floor until you reach a firm, clean surface.
- If you are reusing the tile, scrape the old mortar off the back of the tile too.
- Chip away high spots and loose material so the new mortar bed will not hold the tile too high.
- Vacuum the cavity, tile edges, and surrounding joints to remove dust and grit.
- Dry-fit the tile in the opening to make sure it can sit flush with the surrounding floor before you mix or spread new mortar.
If it works: Both bonding surfaces are clean, solid, and flat enough for the tile to sit at the right height.
If it doesn’t: If the tile rocks during the dry fit, keep cleaning and flattening the old mortar until it sits evenly in the opening.
Stop if:- The surface below is cracked badly enough that it moves or breaks apart while you clean it.
- The tile opening is no longer stable or level because the substrate underneath has failed.
Step 4: Spread fresh mortar and reset the tile
- Prepare the floor tile mortar according to the package directions, mixing only as much as you can use in a short time.
- Use the notched trowel to spread a thin, even layer on the floor in the tile opening.
- For better coverage on a floor tile, press a thin coat of mortar onto the back of the tile as well.
- Set the tile into place, align it with the surrounding grout joints, and press it down firmly.
- Wiggle the tile slightly as you seat it so the mortar beds in fully.
- Use spacers if needed and check that the tile sits level with the tiles around it.
- Wipe away mortar squeeze-out from the tile face and joint edges before it hardens.
If it works: The tile is reset, aligned, and supported evenly without rocking.
If it doesn’t: If the tile sits too high or low, lift it right away, adjust the mortar amount, and reset it before the mortar starts to firm up.
Stop if:- The tile cannot be set flush because the floor below is uneven or unstable.
- Mortar will not bond because the surfaces remain dusty, damp, or contaminated.
Step 5: Let the mortar cure and finish the joint
- Leave the tile undisturbed for the full cure time listed on the mortar packaging.
- Do not walk on the repair or slide furniture across it while the mortar cures.
- Once the mortar has cured enough, grout the joints if they were opened during removal.
- Clean the tile surface and shape the grout joints to match the surrounding floor.
- Let the grout cure before wet cleaning or heavy use.
If it works: The tile is locked in place and the joint is finished to match the rest of the floor.
If it doesn’t: If the tile shifts before cure is complete, remove it again and reset it with fresh mortar rather than trying to force grout to hold it.
Stop if:- The tile keeps sinking, lifting, or drifting out of alignment while curing, which points to poor support or a substrate problem.
Step 6: Test the repair under normal use
- After full cure, press on the tile by hand and walk across it normally.
- Listen for hollow sounds, clicking, or movement compared with the surrounding tiles.
- Check that the grout joints stay intact and the tile remains level after a day or two of regular foot traffic.
- Reinspect the area if this tile was repaired because of a moisture issue, and make sure the source of that moisture is gone.
If it works: The tile stays solid, sounds consistent, and holds up under normal use without movement or new grout cracking.
If it doesn’t: If the tile loosens again, the root cause is likely below the mortar layer, such as movement, moisture, or a failing substrate that needs a larger repair.
Stop if:- More tiles begin loosening nearby after this repair.
- You see recurring moisture, floor movement, or cracking spreading beyond the repaired tile.
Replacement Parts
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FAQ
Can I just add grout to stop a loose floor tile from moving?
No. Grout does not replace the bond under the tile. If the mortar has failed, the tile needs to come up so the old mortar can be removed and replaced.
Do I have to remove all of the old mortar?
You need to remove loose, uneven, and built-up mortar so the new mortar can bond to a clean, solid surface and the tile can sit at the right height. Leaving high spots usually causes a poor reset.
Can I reuse the same tile?
Yes, if the tile comes out intact and the back can be cleaned well enough for fresh mortar to bond. If it cracks during removal, use a matching replacement tile.
Why did the mortar fail in the first place?
Common causes include poor original coverage, dust left under the tile, floor movement, moisture, or a weak substrate. If the same area keeps failing, look below the tile instead of repeating the same patch.
How long should I stay off the repaired tile?
Follow the cure time on the mortar and grout packaging. In general, floor tile repairs need undisturbed cure time before foot traffic, cleaning, or moving furniture back over the area.