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Tiling with Slate

November 28, 2006

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.

12 Comments leave one →
  1. Garry permalink
    November 29, 2006 8:19 pm

    That really is looking great. I love the pattern.

  2. dwight permalink
    July 6, 2008 2:01 am

    Looks like O.J. was in that shower!! Just kiddin. The bathroom work looks great. How many tile saw blades did you use up.

  3. July 8, 2008 2:59 am


    Ha! Yeah, I never gave much thought to how that splash appeared. It actually looks a lot better now after washing it with acid etch and water and a lot of scrubbing all the haze and excess grout is gone. I treated it with a sealer – the grout is bad to get black mold otherwise I found out. It’s been in use going on 2 years.

    As to saw blades – believe it or not, I did the whole house with one diamond blade and it still works fine. This whole master bath, plus two other full baths and a laundry room. The other rooms were done in normal ceramic tile 12″ and 16″ sizes.

    I used a 7 inch diamond saw (wet cut) that was set up like a table saw where you pushed the tile into it. If I had to do it all over, I’d have bought one of the 10″ sliding bridge saws from harbor freight for $199 on sale. With those, the tile stays in place and the saw slides back and forth. You can cut big tiles in one pass and even on a diagonal.

  4. Theresa permalink
    October 26, 2008 6:35 pm

    Your shower looks great! I love your layout and design. My bathroom is in the process of being renovated right now and my contractor is making a shower very similar to yours – with slate tile, dual shower heads, a built-in seat and built-in shelf. How is the maintenance on the slate? (Does it need to be cleaned often and is it difficult to clean?) Do you have any additional pictures of your completed shower?

  5. October 29, 2008 12:10 pm


    I’ll try to post an update in the future once the glass is in. My procrastination on this has a factor of expense, and also a bit of uncertainty how I want to handle the glass. I think I want to go frameless, but haven’t worked out some of the details. The glass would be in 2 panels, one fixed, and one being the door. For the fixed panel, I’ve thought about cutting a relief slot into the tile along the bottom and up the one wall and embedding the glass along with some clear silcone sealant to hold it. Some stainless steel mounting blocks would also be used to clamp it, and also to attach the door panel. the door.

    As -is, we’ve used the shower for 2 years. I highly recommend you seal the tile and the grout with several coats of sealant before you use it. If I had to do this over, I would have butted the tiles together rather than having the 1/4″ grout seam. The grout is prone to develop black mold and you have to stay after it. The slate also seems to attract build up from the soaps, and I think sealants would help. I cleaned and sealed it after the first year and wish I had done from the start.

    Depending on the formulations of the soaps and shampoo that you will use, this may or may not be a significant issue for you. I’ve used a variety of products to try to clean, including most of those found in the store on the cleaning isle, and even took drastic measures with a power washer and concrete acid cleaner to thoroughly clean and strip before sealing.

    All in all, it’s holding up well and I’m still very pleased with it. I learned a lot doing this, and if I had a second one to do, I’m sure it would be better. Isn’t that always the case?

    Thanks for visiting … please share a link and photos of yours when done. I’m certainly interested!


  6. jenevieve permalink
    June 18, 2009 9:18 pm

    hi- i love the shower! we would like to take out the traditional shower basin and put in a tiled one…how do we do that? is there something you buy to tile over? or do you have to frame it out yourself? thanks! jenevieve

  7. June 19, 2009 4:20 am


    There are probably several options, and I might suggest you go down to your local Home Depot or Lowes and thumb through some of the bathroom and tile “how to” books. Bookstores will also have a good selection in the home improvement section. I have “Renovating a Bathroom” by the Tauton Press. You should be able to find a couple good illustrated texts that go through it step by step, and as you look through several of these, you will probably find one that stands out as most applicable to your situation.

    At a high level, you can get a preformed pant made out of sheet metal and cement backer board that you can build up from, or you may elect to build your own. You may be able to get some preformed plastic / fiberglass pans too. As I had a non-standard shape, I built my own.

    Obviously, begin by removing all the old pan and material to the plywood. Are you ripping out the wall tile too? Is the existing tile over sheetrock or cement backer board? ( Sheetrock can be used, but make sure you have the green or purple paper faced as it is mildew resistant. I prefer backer board in 1/2″ because it will not weaken or rot, and is more mold resistant.

    I started from the bare studs and plywood floor and framed out the shower, seat and floor pan. I layerd tarpaper in cascading sheets over the studs and insulation of the wall as a moisture barier. Next, put in a rubber / vinyl membrane and have the drain flange set and sealed for the finished height, taking into account the added depth of your mortar bed, and tile thickness. Next I covered the walls with backer board, laping over the membrane that I had brought up the walls about a foot. You fold/gather the corners but don’t cut it. Insteall the backerboard screws into the studs above the level where the membrane came up behind it so as not to perforate it. The membrane will just be clamped in place by the backerboard, and later the mud bed in the pan. Usually you test the membrane by blocking the drain and filling up with water and letting stand for a day to check for leaks before proceeding. The membrane protects the floor from any water that may work through the grout and mortar bed.

    Next, determine your slope from the perimeter to the drain and snap some chalk lines on the backer board to set depth of the mortar bed around the perimeter. Mix up your mortar ( I used Type S masonry mortar ) and fill up the pan, trowling and using a level to check consistent slope to the drain as you go. Work the mortar to the walls and to the perimeter you established. I didn’t do this as well as I should have, so take your time and do a good job so you don’t have any plateaus or low spots near the walls or you will have puddles that don’t drain as they should. If you don’t get it perfect, you have another chance when you set the tile by filing with tile cement, but get as close to possible while doing the mudding.

    Let this dry for at least a day, then start your title. I did the floor first and then the walls, although I suppose you could reverse this. In the end, it really shouldn’t matter. As you title the floor, be sure to keep checking how you are setting the tiles so that there aren’t flat areas or depressions that will hold water later when you shower. Smaller tiles will work better in the floor area in providing smooth gradients. I used 6″ title and would recommend nothing larger. Ours worked out, but there are a couple low spots. When I finish showering, I just move any standing water with my foot to the drain, and the grout lines seem to do a good job of guiding the rest to the drain in a few mins. This was my first shower project, and I learned a lot and would do better job the second time. As it was I was working almost around the clock trying to finish the house on a deadline, and I found myself saying “close enough” a bit too often at 2am. If we could do this with little to no sleep and working as fast as we could go, you should be able to produce excellent results by taking your time and double checking your work as you go.

    Thanks for stopping by – please stop back later with a link to your work if you post it. I’d love to see it. You can do it! Best of luck.


  8. November 9, 2009 7:30 pm

    We are in the throes of completing a house it’s taken us almost 18 months to build ourselves, 4 weeks till we move in!, AND I chose slate for the bathroom floors and master shower months ago, but after taking my husband to buy it-we’re ready to start any day now, we both started having misgivings when we saw how flaky and dangerously uneven some of the tiles were in any given box, not to mention the installation of such a product is not something we’ve attempted before-always used porcelin or ceramic…we’ve found multi-colored china slate at both Lowe’s and Home Depot in stock, price is similar to yours. I guess my question is, where did you purchase your tile? And did you prep the tiles before you used them i.e. soak tests, pre-seal, etc.? Your project looks great BTW!

    • Michelle permalink
      June 26, 2010 2:52 pm

      We did a slate floor ourselves and bought the tiles from Lowes. I love the floor and plan to do it in our new house.
      I washed and sealed each tile before we installed. Then I was very careful when grouting, I cleaned a lot. After the grout set I scrubbed with a brush. I cleaned the floor till all the residue was gone. Then sealed the floor with two coats of the color enhancing wet look sealer. The floor was well worth the effort and we did not have many problems with flaking or wear.
      I can’t wait to see the slate in our new house’s master bach!

  9. November 9, 2009 9:42 pm


    I bought these at Lowes. Some of the tiles do have more flake to them than others, but once installed, seem to hold up just fine. As you will be using a level when you set them, the mortar will allow them to even out as you install them. If you go to a dedicated title store in your area (hopefully a contractor / wholesale shop) you can fine a lot more varieties of slate, including more consistent color and finish – some with fairly regular surfaces. It’s more expensive, but could be an option if the irregular surface is a concern. I would recommend installing, grouting, and then sealing with 2 coats before any use.

    After 3 years of use, I will say that soap build up is a factor in the shower, and if I had to do it over, especially after seeing some similar slate at a resort in Mexico, I might have done the install with thiner or no grout joints. I definitely recommend the 6″ tiles for the shower floor instead of the 12″ so that you can control the slope better. I think the walls would have looked better with 6″ tiles but the costs per square foot, and time, were higher, so I compromised. Our house took about 2 years, and we built it ourselves too. You have my respect and admiration for taking on this project. You can do it!


  10. January 2, 2011 12:00 pm

    Nice Work!Been tiling for 25 years but still like to keep informed thanking you

  11. Janine L permalink
    July 31, 2011 9:15 pm

    Hi – we have a very similar kind of slate in our rental apartment shower. We’ve been having a lot of problems with it as the sealant our landlord used was not very good so the tiles are starting to split. We only have one shower so sealing frequently is a problem. Any suggestions on super strong sealants we can use? Thanks.

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