Step-by-step fix
Step 1: Confirm the mortar is the real problem
- Press on the tile with your hand and then step on it carefully to feel for movement.
- Tap the tile and nearby tiles with the handle of a tool and listen for a hollow sound under the problem tile compared with solid tiles nearby.
- Check for cracked, powdery, or missing mortar at the tile edge or in any exposed area around the repair.
- Look closely at the tile itself. If the tile is badly cracked through the body, plan on replacing the tile too instead of only replacing the mortar.
If it works: You have a loose or poorly supported tile and the failed mortar appears to be the main cause.
If it doesn’t: If the tile feels solid and the issue is only dirty or missing grout at the joints, this is probably a grout repair instead.
Stop if:- The subfloor feels soft, spongy, or water-damaged under the tile area.
- Multiple tiles are lifting or cracking across a wide section of floor, which points to a larger floor movement problem.
- The tile is part of a heated floor system and you are not sure where the heating elements run.
Step 2: Clear the area and remove the tile if needed
- Move furniture, rugs, and anything breakable out of the work area.
- Put on gloves and safety glasses.
- If the tile is already loose, lift it straight up carefully and set it aside on a padded surface.
- If the tile is still partly bonded, work a putty knife or margin trowel under the edge and loosen it gradually instead of prying hard in one spot.
- Keep track of the tile orientation so you can reset it the same way if you are reusing it.
If it works: The tile is out or loose enough to expose the failed mortar bed without damaging surrounding tiles.
If it doesn’t: If the tile will not come up without cracking and you need to save it, slow down and remove more mortar from the edges before trying again.
Stop if:- The tile breaks into sharp pieces that make the repair unsafe to continue without replacing the tile.
- You uncover major cracks in the substrate or large voids under several surrounding tiles.
Step 3: Remove all loose mortar and clean the bonding surfaces
- Use the putty knife, margin trowel, or chisel and hammer to scrape out loose, crumbly, or hollow-sounding old mortar from the floor and the back of the tile.
- Leave only firm material that is still well bonded. Anything weak enough to flake off should come out.
- Vacuum the cavity, tile back, and surrounding joints thoroughly to remove dust and grit.
- Wipe the tile back and the repair area with a damp sponge, then let the surfaces dry to the touch unless your mortar instructions say otherwise.
If it works: The repair area is clean, solid, and free of loose debris that would weaken the new bond.
If it doesn’t: If old mortar is still glossy, contaminated, or breaking apart, keep cleaning until you reach a sound surface.
Stop if:- The substrate is crumbling deeply instead of just having a thin failed mortar layer.
- You find active moisture coming up through the floor or trapped water under the tile.
Step 4: Apply fresh floor tile repair mortar
- Mix or prepare the floor tile repair mortar according to its label so it is workable but not runny.
- Spread a thin layer onto the cleaned floor area, then add enough mortar to support the tile evenly.
- If the tile back has deep ridges or voids, key a thin coat of mortar onto the back of the tile as well.
- Set the tile into place and press it down firmly with a slight wiggle so the mortar beds in fully.
- Adjust the tile until its top surface sits even with the surrounding tiles and the joint spacing looks consistent.
- Clean off squeezed-out mortar from the tile face and joints before it hardens.
If it works: The tile is seated evenly, feels supported, and the fresh mortar is in full contact under the tile.
If it doesn’t: If the tile sits too high, remove it right away, scrape out a little mortar, and reset it before the mortar starts to firm up.
Stop if:- The tile rocks even after adjustment, which usually means the mortar bed is uneven or the substrate below is not flat enough for a simple reset.
Step 5: Let the repair cure without traffic
- Keep people, pets, and rolling loads off the tile for the full cure time listed on the mortar packaging.
- Do not wash the area or flood the joints while the mortar is curing.
- If needed, mark the area with painter's tape or a small barrier so nobody steps on it too soon.
If it works: The mortar has time to harden without the tile shifting out of place.
If it doesn’t: If the tile moves during curing, lift it before the mortar fully hardens, clean off the disturbed mortar, and reset it with fresh material.
Stop if:- The tile sinks, drifts, or loosens again during cure, which suggests the base below is unstable or the wrong repair material was used.
Step 6: Test the repair in normal use
- After full cure, press on the tile by hand and then walk on it normally.
- Tap the tile again and compare the sound with the surrounding floor.
- Check that the tile surface is still flush with nearby tiles and that no edge lifts when weight is applied.
- Watch the area over the next few days of normal use for renewed movement, cracking, or hollow spots.
If it works: The tile stays solid, level, and quiet under normal foot traffic, showing the mortar replacement held.
If it doesn’t: If the tile loosens again, the problem is likely deeper than the mortar alone and the floor base or tile itself needs a closer repair plan.
Stop if:- The tile cracks again, nearby tiles start loosening, or the floor flexes underfoot, which points to a larger substrate problem.
Replacement Parts
Repair Riot may earn a commission from qualifying purchases, at no extra cost to you.
FAQ
Can I reuse the same tile when replacing the mortar?
Yes, if the tile is not cracked and the back can be cleaned down to a sound bonding surface. Reusing the tile is common on small repairs.
Do I have to remove all of the old mortar?
You need to remove all loose, crumbly, or poorly bonded mortar. Sound material can stay if it is firmly attached and leaves enough room for the new mortar to support the tile properly.
Why did the tile come loose in the first place?
The usual causes are poor bond, movement in the floor, moisture, freeze-thaw damage in some locations, or traffic before the original mortar fully cured. Replacing the mortar helps only if the base below is still solid.
Can I walk on the tile right after resetting it?
No. Fresh mortar needs cure time. Wait the full time listed on the product you used before normal foot traffic.
What if the tile still sounds hollow after the repair?
A slightly different sound is not always a failure, but if the tile also moves or feels unsupported, the bond is not good enough. The tile should be lifted and reset again after checking the substrate.