This post explains how to demo, prep, and re-tile a kitchen space with a plywood subfloor. Replacing a tile floor can seem challenging, but it’s actually pretty straightforward with the right materials and tools.
This is a kitchen in a 1950s -vintage pier and beam bungalow that had already been renovated with new cabinets, countertops, and appliances. Unfortunately though, the previous renovator had really screwed up the flooring redo.
The original kitchen flooring would have been either finished hardwood (same as the rest of the house) or first-generation linoleum tiles laid on unfinished hardwood. Whomever renovated the kitchen ripped whatever was originally there down to the joists and rebuilt the kitchen floor with OSB plywood (good), a layer of 1/4-in thich high density concrete backerboard (also good), and a top layer of 24×24 inch mottled brown ceramic tile (not good).
The top layer of ceramic tile clashed with everything and had also been installed badly. As a result, it was both ugly and cracked.
The good news was that removing the old tile was easy. When a sloppy installer tries to do a tile job quickly, they often spread thinset over a too-large area. The thinset then skims over before the tile starts going on, which makes the tile not actually stick to the thinset. This is one very common reason why ceramic tile cracks over time.
The clients were worried that the new tile would need special materials or prep, due to the old tile being cracked in spots and missing a lot of grout. Those can be symptoms of a plywood subfloor that’s too flexy for a straightforward tile install.
But in this case, both the cracked tiles and missing grout were simply symptoms of a bad previous install. Paradoxical good luck, that.
Since there was plenty of headroom to check out the foundation framing, it was easy to verify that the subfloor was actually plenty sound for a tile install using just the right kind of modified thinset. Kudos to the 1950s homebuilder on the Austin eastside who actually used 10-in thick beams for floor joists!
The only wrinkle was the floor slope. It was crowned in the middle, so making the final finished floor tile level would require an extra-thick thinset layer (and therefore require removing every bit of the previous thinset). And, while the tiles came up easy, removing all the previous thinset was a slow couple inches at a time demo job. So, that was a drag.
Also, the current kitchen cabinets were installed on top of the existing tile. Since the cabinets weren’t getting replaced, demo required cracking apart the existing tile right up to the edge of the base cabinets. This required lots of chiseling, lots of hammering, and lots of sweeping up little bits of ceramic all around the perimeter of the kitchen.
But aside from these challenges, the overall process was straightforward:
- Remove all existing tile and thinset down to the plywood subfloor (shuffling around the stove and refrigerator, and cracking through the tile laid underneath the existing cabinetry)
- Remove the existing quarter-round baseboard trim
- Vacuum the surface to make it completely dust-free (to ensure good thinset adherence to the existing concrete backerboard layer)
- Install the new 12×24 inch porcelain ceramic tile using the proper crack-prevention modified thinset with an extra-thick bed to compensate for the subfloor unevenness
- Grout the new tile
- Replace the quarter-round baseboard trim, caulk the baseboard seams and nailheads, and finish paint
Simple in theory, but sneaky painstaking in practice. From chiseling out every square inch of existing thinset to finish painting the last bits of replacement baseboard quarter-round, it took a full 5-day workweek.
For removing badly-adhered ceramic tile, just about anything will do. For example, these tiles came up with little more than a simple crowbar pull.
But for removing thinset? If it’s a large space without folks living in it, then a small pneumatic hammer with a wide chisel blade is the way to go. But, if you don’t want an enormous amount of dust (and/or you’re working around folks who actually want to live in their house while the work is going on), then there’s no substitute for a simple hand sledge and wide-blade cold chisel.
Also, since the previous renovator had installed the new cabinets on top of all the (badly installed) reno tile, this needed some skilled demo to crack through the existing tile all around the cabinet perimeter. Again, a simple hand sledge and cold chisel does the trick on that.
The Tile (re)Install
Pretty straightforward with a big 1/2-in square notched trowel for the low spots and a 1/4-in square or v-notched trowel for the high points. The main challenge was floating the entire prepped floor with a thick enough thinset layer to make the entire finished floor level.
Porcelain ceramic tiles have square edges, which is pretty unforgiving for a 1/8in grout line install. If the tiles are more than 1/16-in out of flush, then you’ll really feel the sharpish exposed edges when walking on ’em in your stocking feets.
Grouting and Finish!
The clients chose a light grey grout that really framed the dark grey modernist tile. That makes for a nice design tip — when in doubt, go grey grout. It’s light enough to look really spiffy when clean and dark enough to not show too much dirt in between.
For the diy advice, one simple word — sanded. Always use sanded grout for floor tile installs, especially for kitchen or bathroom floor tile. Sanded grout is stronger, more stain resistant, and more slip proof than unsanded grout.
The result for this job was a spiffy new kitchen floor that now matches the character of the rest of the house!