Tiling with Slate
As previously reported, we moved into our home several weeks ago, and the first days were a little better than camping, but with each passing day, refinements are beginning to appear. Sunday, we ate our first dinner – sitting at a table. This coming weekend, we are hosting a cookie baking get together for family. It’s great to host events like this for a couple reasons. First, it’s always great to see family and to celebrate time in a home they have contributed so much toward. Secondly, their impending visit creates a deadline for us to complete a couple key projects, most notably the master bath.
Last night, we finished grouting the last of the 330 square feet of multi colored slate tile that comprise the shower, tub surround and floor.
The subfloor was mudded with thinset, and 1/4″ thick cement backerboard to level and seal the plywood. Then another layer of thinset mortar and the gauged 12″ slate tile was applied in a color randomized format, drawing from about a 35 boxes of tile. The walls of the shower and tub surround were 2X4 framed, then covered with overlapping layers of 30 lb roofing felt as a vapor / water barrier should anything make it through the subsequent layers of 1/2″ thick cement backer board (for greater rigidity), plus thinset, tile and grout. The Shower pan was constructed of a heavy vinyl liner, with folded corners and tested with blocked drain in place to hold water. No staples were applied below the sill. The backer board overlapped this, and with the exception of the entry way, no screws were placed below the finished tile level. I made my mortar bed with type S mortar, mixing 60 lb bags and troweling the mixture to pitch to the drain. I would do this over again if I could because I got two low corners. At the time, I thought I would make up the defects with extra thinset mortar. So doing, I reduced the problem, but didn’t fully eliminate it. I used 6″ square tiles for the floor as they made it easier to slope on 2 axis leading to the drain than the 12″ tile. Local costs may vary, but the 12″ tile were about $2 and the 6″ tiles were $1 each. So the 12″ tiles worked out the be have the cost for the same square area, and produced fewer grout lines. All the tile was cut with a wet, smooth rim diamond saw. Unlike smooth ceramic tile, natural slate has numerous ridges and clefts which capture the grout and make cleaning the grout off the tile quite problematic, as well as rapidly shredding your collection of sponges.
The shower measures 7′ X 4′ and 9′ in height. We added dual shower heads and controls, as well as a handy bench seat and built in niche to hold soap, razors, etc. Wet, the tile colors change – deepening and darkening. You can see the dried grout haze here. I plan use a stiff bristled brush to try to remove the haze, followed possibly with a cleaner like CLR which will dissolve lime. Once we are satisfied that we have the residue off the tile, I’ll apply a sealant with a small roller.