Everything you need to know about installing encaustic cement tile flooring outdoors

It’s the fifth week One Room Challenge, and the finish is in sight!

The main feature of our entire makeover is the expanded patio and bold patterned encaustic cement tile. This type of tile has ~1/8-inch thick cement pigment integral to the 3/4-inch thick tile. Encaustic cement tile is finicky to work with, but with the proper preparation the end result is beautiful and durable*



We sealed the concrete slab about a week before we got started tiling with two coats of concrete waterproofing sealer. This is an important step because this layer of sealant should block cement efflorescence from blooming through the encaustic cement tile — especially for not quite cured slabs (concrete slabs generally need about a month to fully cure) though we would still recommend this step for well cured slabs.

Encaustic cement tiles are porous, like natural stone, so to prevent mortar stains, and pigment bleed from cutting we sealed the pigment side of all of the tiles we intended to use with a water-based sealer. After allowing the sealer to fully absorb into the tiles, we stacked them up neatly on one end of the the slab.

We followed the instructions on our mortar mix, in roughly 25-pound dry mix batches (~2/3rds of a 5-gallon bucket). The process for laying the tile was to wipe the unsealed back of each tile with a wet sponge (to prevent it from soaking up all the moisture from the mortar so it sets properly), and then back-butter the tile with mortar and then lay the tile in a 1/2-inch square notched trowel bed of mortar. We were using a tile leveling system, so putting clips and wedges in and then tightening the wedges as we progressed was also an important step.

We had a complication, in that we had an existing section of tiles to weave into, as well as a slab joint to hop. We did the seam first to establish the pattern over to the new slab for about 2 tiles deep. We then went from the back of the slab to the front.

We weren’t quite square enough and ended up having to modify about 10 hex tiles (out of 104) to fit correctly. This means that our pattern isn’t perfect, but also it is hard to see where we’re off as the pattern is so busy. If I had to do it over again I would work along the long side of the slab and let the joints flex out to accommodate the imperfections.

We finished the field on the first day, and then rented a tile saw to finish up the border and the 10 field tiles that needed modification. After letting the mortar set for 24 hours we grouted the joints, and after another 24 hours we sealed the tile and grout — first with the water-based sealer, and then with the nano-particle sealer.

All told the tiling, grouting, and sealing took about 14 hours of work for ~250 square feet.

*Disclaimer — we are installing this tile in Houston, Texas, which has a mean yearly temperature change of ~45 degrees Fahrenheit. We don’t recommend installing encaustic cement outdoors in climates with more drastic temperature swings, or with the possibility of snow cover, even with admixture enhanced flexible mortar and grout — the medium-format (or larger) tiles are just not flexible enough and could crack. Further, our tiles will be exposed to direct sunlight, which will fade the pigment over time. This can be mitigated with a UV-blocking sealer reapplied yearly, but the tile will still fade.

Make sure to check back next week for the big reveal and also follow along with everyone else participating in the challenge!

This post was sponsored by The Tile Shop. All opinions are my own.

This post was written for the  Collected Eclectic blog.

Collected Eclectic was a passion project focused on recording the process as Grace and Michael van Meurer transformed their builder grade home in to something special.

124 blog posts were published between 2018 and 2021. Explore the complete Collected Eclectic archive here

Learn more about the project here

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