Slate Shower [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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02-07-2010, 02:13 PM
Hello All, I've been scouring the thread history here and I must say am quit impressed with the level and amount of advice given....learned alot already.
I have a raw (durarock walls, rubber liner covered with tapered concrete to drain) shower stall in my basement ready for tile and have convinced the wife to let me go all Slate. I'm thinking 2x2" slates on sheets for the floor and then 12x12" tiles's on the walls.
I have slated a bar floor area approx. 8 x15' previously so I have a decent grasp of what I am taking on and have at least some basic experience working with slate setting.
A few questions for the pro's out there:
1. I've been getting very mixed info about the use of slate in high moisture areas...any input? I realize sealing will be of utmost importance but is re-sealing going to need to be a constant worry?
2. What type of mortar would be best for a shower application?....any recommendations on or against pre-mixed?...I had a slight disaster mixing bags previously and would prefer not to.
3. seal slate heavily before grouting? Sanded or non sanded grout? The gaps on the 2x2" sheets are about 1/8" max. Will prob. go w/1/4" spacing on the walls.
Anything you can add to get me started off in the right direction would greatly be appreciated.

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02-07-2010, 03:18 PM
1) Your slate will tell you if it's good for a shower. Soak a few samples in some water over night, then scrub them with a nylon brush. If the tiles start to flake apart and/or the water turns muddy, your tiles are telling you not to install them in a shower.

2) Premixed "thinset" should not be used in a wet area. Period. Use a good quality latex modified thinset and learn to mix it. Start with a small batch to use on a test board. A $15 bag of thinset is not too much to spend to learn this valuable skill.

3) Seal the top surface of the slate before installing. Keep the sealer out of the grout lines so the grout will stick. Space the sheets to match the groutlines in the sheets. I.e. if the individual tiles are 1/8' apart, space the sheets 1/8" apart. 1/4" groutlines for the wall tiles is OK.

02-07-2010, 08:31 PM
A true slate is quite hard and essentially impervious to moisture. A lot of stuff sold as slate is more like compressed mud or shale, and will fall apart if it gets wet. Lots of the stuff sourced in China and India looks pretty but is quite soft. Not all, but lots...

02-07-2010, 10:48 PM
Maybe check out some of the Brazilian slates like the Brazilian multicolor. It is darker than your indian multicolor (rajah) but very dense for a slate. I have used this in several shower installs and for exterior use and have had no problems with it.

02-08-2010, 10:26 AM

I have a raw (durarock walls, rubber liner covered with tapered concrete to drain) shower stall in my basement ready for tile

Is there "tapered concrete below and above the rubber liner? You need what is called a "preslope" below the liner.

02-08-2010, 10:34 AM
Thanks for the reply's guys.
I'm performing the "bucket test" as we speak I have samples of each the 2x2" sheets and the 12x12" tiles soaking. I believe they are Vermont slate which I've found a few threads here saying it is a good, dense slate for showers.
Point noted, bbcamp, I will get a bag and start it a water mix or special liquid hardener to add to the powder for showers? Peanut butter consistency?
I'm nervous and excited all in one on this project.
Few more questions if you would please:
1. Is it o.k. to just "backbutter" the wall slates and install as long as long as I'm getting the proper amount of thinset on them?...I saw this technique on 'Bathtastic' over the weekend and it seems to be a cleaner install for a person such as myself who seems to find a way to get the stuff everywhere except where it's needed!
2. Should I clean the back sides of the slate before installing? When I did the slate bar floor w/ the 12x12" slates I was having a tough time getting the thinset to stick to the back sides of the tiles. I really hard to work the thinset back & forth and up & down on the tiles to get it to adhere.

Houston Remodeler
02-08-2010, 10:34 AM
Before the soak test (a definite must, no matter what the tile salesgal says) take a look at the edges of a few tiles. If you see the tiles de-laminating, put it down. If you see cracks along the edges, put it down. A good quality slate will be even, whole pieces without a bunch of strata on the edges. Open a box and look at a few tiles. The tops should be nice and flat. If they aren't, you shouldn't be able to peel off any more of the top layer. Give a few tiles a good thumping. Like buying a cantaloupe. Listen to if the tile is whole or there are fissures.

1- yes, backbuttering is a fine technique.

2- yes, the tiles will be dusty. a quick swipe with a damp sponge will get the dust off of any tile

02-08-2010, 10:37 AM
What do you have for waterproofing behind your durock walls? No matter what the people at the Big Box told you, that stuff is not waterproof either.

02-08-2010, 10:44 AM it a water mix or special liquid hardener to add to the powder for showers? Peanut butter consistency?Depends on what you buy. Some modified thinsets have the admix already in the bag, others require something in a jug. If you use Versabond, for example, it needs only water to make a modified thinset.

Peanut butter consistancy is good. Creamy, not crunchy.

Backbutter is a good technique for adjusting the amount of thinset you need for different thickness pieces. You still need to burn in a coat of thinset on the walls to get good bonding.

Keep a couple of buckets of clean water and some sponges handy to keep you, your tools, and your tiles clean. Your labor is free, so you don't need to be in a hurry. Take your time and have fun.

02-08-2010, 11:23 AM
you guys are awesome, thanks a million.

02-08-2010, 06:10 PM
O.k. guys, now what?:(
I went to check the status of my slate "bucket test" and the 2x2" slates on the mesh sheet all fell off the mesh sheet and were at the bottom of the this normal?...what will happen once they are installed on the shower floor? Should I just scrap my dream of the slate mancave shower stall?
It appears as though the 2x2" slates are glued onto the mesh backing, which I see is very common with ceramic, porcelein, etc. and I just cant see how the thinset will even penetrate the mesh and adhere to the tile.....maybe I'm thinking into this too much but the only reason I am an avid DIY'er is because I was born and bred with some decent skills and am somewhat of a perfectionist....especially when it's my home!

Otherwise after being submerged for 24 hrs. the slate (2x2" and 12x12" tile) don't appear to be the slightest bit affected. The water in the bucket was still crystal clear and trying to rub/shale the tiles was not happening....I think this means they are of decent/proper type.

Brian in San Diego
02-08-2010, 06:28 PM

I wouldn't worry that the tile fell off the least I wouldn't lose sleep over it. Once the tile is set with thinset the mesh backing serves no function I can think of. It's main person is to hold them in some semblance of order to install them. Once that's completed and the tile is grouted you shouldn't have any worries.

I don't know who will maintain the shower but you may want to consider looking for porcelain "look-a-like" in lieu of real slate. It is way more easier to maintain. If you aren't prepared to squeegee and wipe down the shower after EVERY use then you may be back in the cleaning forum in less than a year asking for advice to clean and restore it.


Houston Remodeler
02-08-2010, 06:32 PM
Add one more vote for 'look alike' tiles. The maintenance is MUCH lower. Add the possibility of some unsuspecting, trying to be helpful person, using some wrong product to clean your shower may accidentally damage it. Master tile and Daltile both carry nice "look alike" tiles in both ceramic and porcelain, complete with matching bull noses, corner pieces, accent trims, and listillos.

02-08-2010, 06:41 PM
Alright guys, look alikes it is.... the wife is thrilled, I am crushed but the scale just keeps tilting to the negative side for an awesome slate shower.
...back to the drawing board...or should I say, Tile Warehouse on Fullerton & Western....anyone in Chicago know this place?