How to Replace Cracked Floor Tile
Tools and Gear
Thin Set Mortar
Floor Tiles Placed
Restoring a Ceramic Tile Floor
An old friend from way back asked me if I could replace some cracked floor tiles. Of course I agreed. I love doing tile…
So I visited and saw that a row of tiles had cracked right near the center of the room. This indicated that the concrete slab foundation had settled, that a crack had formed underneath and transferred up to crack the floor tiles above. After noticing that the room was actually a back porch that had been converted into a room, I figured out that the added weight of the walls of the room addition had caused settling. Because the addition had been there more than five years, I figured there would be no more settling. Therefore, it was okay to replace some cracked tiles.
First thing was to lay out the tools, to make sure I had everything. Nothing worse than having to leave a job to go get something. Then something else comes up, priorities get shuffled, and the job never gets done. Not my style.
Bucket for clear water, bucket for mixing grout, tile nips just in case, masking tape, grout sponge, scrubber sponge, spreader, hearing protection, eye protection, grout float, notched trowel, dustpan and brush, razor scraper, knee pads, flat tip screwdriver, grout remover tool, scraper, thin set mortar pre-mix, hammer, work gloves, rubber gloves, drop cloth, mason’s chisel…yeah, that ought to do it.
And a drill bit. No drill, just a carbide-tipped hammer-drill masonry drill bit.
The first step was to identify all the cracked tiles. I examined them closely and marked around them with masking tape. Just to make sure I didn’t bust out the wrong tiles. It happens. A sweaty brow and eye protection can degrade vision enough to make it hard to see which tiles need to come up, so I taped around them so I wouldn’t do more work than I’d been asked to do.
Then I needed to punch into the first tile to get things started. The most popular method is to use a drill with a masonry bit to drill several holes side by side, wide enough to get a masonry chisel started on the first tile. I’ve tried that and managed to drill down too far, into the underlying floor. Instead, I prefer to just hold the drill bit in my hand like a punch and drive it into the tile with a hammer. It causes a nice spider-vein crack. By punching a second hole a couple inches away it leaves a good oval-shaped hole to get the chisel started.
After the first tile was out, I could get my chisel under the edge of the next tile and had the cracked tiles busted up and removed after a few minutes of hammering. About five minutes per tile, actually. Most of the old thin set mortar underneath remained and I left it there. No need to remove it, just knock it down low enough so that the new tiles would set level and square. I also left much of the old grout in place, not wanting to risk cracking the adjoining tiles. I just chiseled away enough for the new tiles to fit properly.
Then I cleaned the area thoroughly. I brushed up as much debris as possible and then used a shop vac to remove anything that might still be lurking in the cracks and crevices. Then finally I wiped the area where the old tiles had been removed with a sopping wet sponge. This wet down the old thin set mortar, made it more likely to bond with the new thin set mortar.
Next I dry-fit the new tiles to ensure they would seat correctly. There were a couple that would not lay flat so I had to chisel away a few high spots in the old thin set mortar, or chip away some old grout. I then lifted the tiles out and used my notched trowel to apply thin set mortar to the exposed floor. The ridges of the old thin set had wide enough grooves between them to accept enough new adhesive to get the job done.
I placed each tile on edge at first and let it fall into place and listened for a soft thump, to ensure there was enough mortar under it. A couple of times I heart a ‘clack’ and lifted the tile to see where the dry spot was, added a little more mortar to cover it, dropped it back in. Good to go.
With all the tiles in place, I stood and looked down at them to see if they were straight. Had to press and twist a few, checked the corners for level, made sure it was good. Then I took a two hour dinner break to let the mortar dry. The home owner bought me lunch.
Next I mixed some grout and spread it along the seams of the new tiles. Grout comes in a wide variety of colors and textures and strengths. Fortunately, the home owner had some left-over grout from the original tile job so I didn’t have to go through the arduous process of trying to match the new grout with the old. I plopped a gob of grout at the corner of a tile and worked it into the joints with my grout float, kept plopping down gobs and pressing it in. Went back and scraped away excess grout with the float, moved along the joints. Then I inspected the joints and added a bit more grout where it was needed. Then I removed as much grout as I could get off the tiles with the float and scraped it back into the bucket.
Then I took my grout sponge and wrung it out until it was nearly dry and wiped gently, with no downward pressure, across the joints at an angle, to get the new grout level with the edges of the tile. I had to wring the sponge in a bucket of water about a half a dozen times.
I changed the water in the bucket and then wrung the sponge to where it would drip a little. I wiped the excess grout off the tiles, careful to not touch the joints. Getting the wet sponge too close to the joints would dig out the grout and leave a deep crevice and I didn’t want that.
Finally I changed the water one last time and wrung the sponge to make it nearly dry and wiped along the joints with some downward pressure, to make the depth of the new grout match the depth of the old grout of the adjoining tiles that had not been replaced. And then one last wipe of the tiles. It is far easier to get the grout haze off them before they dry completely. The final wipe did not have to get every little bit of grout off the surface of the tiles, it just had to remove the binder. After the tiles dried completely, a dry cloth took the haze off as if it were a light coating of dust.
Fortunately, the job went cleanly. I did not have to use the floor scraper or razor scraper or scrubbing sponge to remove dried-on mortar or grout.
With the job done, I packed up my stuff and admired my handiwork and accepted the praise and handshake of the old friend who owns the house. It was a good way to spend the day.