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Slate tile flooring. Anyone have any...

steve_penney's picture

We are thinking of using slate tile in our kitchen, dining room, and utility room. We have looked at several options: Gauged vs. ungauged, multi colored vs. gray, 12 " vs. 18 ", etc. Anyone have any experience installing it? Is it tough to install the ungauged? How about using it in the kitchen. Is it prone to stain or any other problems? What is considered a reasonable price/sq. ft?



(post #164221, reply #1 of 18)

We were going to use slate in our kitchen when we built about five years back. Everyone we talked to who had it said that staining was terrrible so we decided against it.

(post #164221, reply #2 of 18)

Used slate several years ago in our kitchen/mudroom area. Very pleased. Installation was easy, came out beautiful after it was sealed. No staining problems I recall, who gets on their hands and knees and looks for stains anyways? I prefer the look of the dark gray, versus the mixed/red/green whatever they offer. Use of a grout release almost mandatory.

(post #164221, reply #3 of 18)

if you want the floor fairly flat you should go with gauged, gauged= less labor/ higher material cost. if you are doing this yourself and have all the time in the world and are also very patient go for the ungauged, personally i will never lay an ungauged floor again, unless it is some sort of slab or really oversize material.

(post #164221, reply #4 of 18)

Steve, are you in Port Aransas, TX?

If you have to ask re: gauged vs ungauged, I suggest you don't even consider ungauged. Unless you are very good with setting in wet mud.

Mutlicolored vs others is really an aesthic choice you'll have to make. Although, one caveat is that the multicolored comes mostly from India and you end up with alot of tiles with razor thin edges/corners which will up your waste factor somewhere to 20% or more.

Use of slate as interior flooring, even in the kitchen, can be quite attractive. Being derived from sediment clay, slate will stain because of it's porosity. Simply decrease the porosity with a sealer and you're fine. I use Glaze N Seal products.

What I like about slate as interior floors is that over the years it wears to a beautiful soft patina while keeping it's color. The sealer can give you a matte or gloss finish. The gloss sealer will darken the tile a bit but that highlights the colors.

Something for you to consider before deciding on the slate is what problems at thresholds and transitions do you anticipate? Even with gauged slate (T variations >3/8") you have to build up some tiles to get a flate floor. This could mean you'll be shaving every door and get creative at some transitions. So you really have to think of how installation methods will be limited by jobsite parameters.

(post #164221, reply #5 of 18)

I installed ungaged India slate with thinset on a 3/4" drypacked mortar bed over 1" subflooring. I didn't have any problems with major thickness changes. Though I was careful to segregate the extra thick ones from the thinest. The difference was less than 1/4" and they went under the open riser staircase. There was virtually no waste. I think it helps the final "look" to alternate the grain direction and colors. At $.89 per 12x12 they made a very cheap, very pretty entry.


(post #164221, reply #6 of 18)

I used gauged slate for my fireplace surround/hearth. I wish I had used it for my entry as well. It has a really nice warmth to it. I would hesitate to use it for a kitchen floor though, due to the uneven surface. I think you would end up with a wobbly table, chairs, barstools, etc.
Installation was a bit slower than tile, but in time I got the hang of it. I think ungauged would be a bit more tedious. The upside is that you aren't going for quite as much of a "finished" look as you are with tile, so you will be the only one who knows where the mistakes are.

(post #164221, reply #7 of 18)

Another vote for the gauged one. I recently did about 150 sq ft using ungaged slate. Their thickness ranged from 1/4 in to 7/8 in. Many of them were thin on one edge and thick on another edge. The cost of gauged slate is small compared to the hassle of setting ungauged ones.
Slate is rather soft, and it seems like it is forever losing little flakes, dust etc.
Several tile companies are making ceramic tile that looks very much like slate. It is easier to keep clean, harder to scratch. Might be worth a look.

(post #164221, reply #8 of 18)

We have installed numerous gauged slate floors, including the multi-colored India tiles. All were satisfactory with one caveat. The slates are very difficult to grout if you are at all fussy about grout haze in the flakes in the surface of the slate. We have tried every possible sealer and grout release combination with no real success. The only method that works perfectly is to tuck point all the joints with a dryish mortar. This takes a lot of time but is the only method that we will use for a paying customer.

(post #164221, reply #9 of 18)

Right off the bat I think of, "...compared to what?" Compared to a factory made tile, then, yes, the slate is difficult to grout. But if you change your grouting methods/technique you can acheive satisfactory results. ('Satisfactory' does NOT mean so-so, I guess I can learn to live with it.)

After the initial set of the grout (10-25 minutes) I use a sponge with minimal water flat on the slate in circular motions. I'm not trying to do anything but smooth the grout in the joint. Working 15-25 sf at a time, I rinse the sponge and drag it across the slate pressing down with moderate pressure. Do this step about four times without letting the surface of the tile dry out between steps should give a very clean surface. Use minimal water at each step.

(post #164221, reply #10 of 18)

Slate is dificult to intall and impossible to grout. It will not accept topical sealers, and usually does not accept penetrating sealers. This is because of slates high oil content, which coincidently make it one of the better roofing products around.

My advice is to pre-seal the product with the absoulte best sealer you can buy: Miracle 511, or Aqua-Seal. This will act as a grout release. I think Rich's comment about grouting in very small batches is good advice.

(post #164221, reply #11 of 18)

If you do it right you only have to do it once.

I use Glaze N Seal products on natural stone. I gave up on AquaMix a long time ago. And, hoo boy, I can't let this one go: tell me more about slate's "high oil content". In situ, it could be considered an oil--as in petroleum--bearing strata, is that what you mean?

My words about working in small areas were misunderstood. When spreading grout, I'll cover more square footage. How much depends on type of tile (ceramic/saltillos/stone) to be grouted, ambient wx conditions, direct sunlight, etc. For a slate floor, I'll grout at least 100 sf at a time. The '15-25 sf' was in reference to the cleanup steps. The number is determined mostly by what I can reach with minimal movement across the floor. Working in a smaller area during cleanup is all about effieciency. It allows me to concentrate on that area before moving on to the next. Results in less time on my knees and a better clean up than if I just blasted across the floor.

Also, not knowing the skill level of folks here I hesitate to suggest working a larger area. Having the grout cure out of control and 'get away' from you is a real problem.

(post #164221, reply #12 of 18)

I have used the method that you describe. It may be that I just don't have your touch but I have never had a similar problem grouting tile. I have gotten slightly better results grouting small area, 15-25 sf, but even there some grout sticks in the cracks of the flakes. For some people this is not even a slight problem but as a contractor I find it risky to make that judgement in advance. If I could find someone to do a better job of it than I can, I would gladly do so.

(post #164221, reply #13 of 18)

I'm sorry, I didn't mean to boast. One thing about me is I'm quite fastidious about those kinds of things. Makes me neurotic at times, but if I'm pleased I know my customer will be. A perfectionest who bangs my head against that wall, that's me. But, I'm getting better.

(post #164221, reply #14 of 18)

I did not put slate in the kitchen but a large entry instead. My comments are as follows:
Use gauged to get even close to a flat floor.
I bought direct from Sheldon Slate; cost was $1300 for 180 s.f. delivered (to Northern Illinois).
I chose unhoned instead of honed (Honed is almost as smooth as ceramic). Unhoned will shale (flake) but I was told that the amount of flaking decreases over time.
Sheldon has a website in which they have a variety of patterns. When you have decided on a pattern, you then choose the color mix. Sheldon was very helpful in defining how much of what to order. We went with the Random Ashlar #9 pattern using only 5 of the available 7 or 9 colors.
Good Luck, I think you're going to like the results.

(post #164221, reply #15 of 18)

Check the "gaged" statment from the manufacture. I recently used a gaged product from the UK (looks greats) but 10% of the tiles were warped corner to corner 3/4" and 20% were warped 3/8" or less corner to corner. The tile had a clef faced and the thickness varied from 1/8" to 5/8". The manufacture said to shear off the high spots with a 1" cold chisel after installation. Instead I took the time to sort the tiles and match the thickness and the pattern. The end result was worth it, but it took alot of time.

(post #164221, reply #16 of 18)

We are thinking of using slate tile in our kitchen, dining room, and utility room. We have looked at several options: Gauged vs. ungauged, multi colored vs. gray, 12 " vs. 18 ", etc. Anyone have any experience installing it? Is it tough to install the ungauged? How about using it in the kitchen. Is it prone to stain or any other problems? What is considered a reasonable price/sq. ft?



Slate floor (post #164221, reply #17 of 18)

I used some salvage chaulk boards for my floor. The thinset had to be extra soupy and I needed to press them in with two bys and HD screws. Have a look at:

Jon (post #164221, reply #18 of 18)

I was mesmerized............but pis'd off that the video went so fast through the pics.

Do you have a string of those photo's on one of those public photo sites? a guy could advance the slide show slowly?


take the time and post the photo's here?


I'd sure like to take a look at the changes you made.


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