installing slate tile [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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08-09-2001, 06:16 PM
Hi all. I found your forum through DIY while searching the internet for information on installing slate tile.
I recently purchased 150 sq. ft. of natural slate floor tile and want to install it myself. I have found little to no information on the subject. What little I've found is conflicting. I have never set tile before, but assume it would be much like ceramic.
The tiles I have are nasty, of course. What can I use to clean them before setting, or is cleaning needed?
As tiles are extremely uneven, should edges be honed for eveness at the joints? Should tiles be sealed prior to grouting to ease cleaning?
Any information is greatly appreciated.

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John Bridge
08-09-2001, 06:35 PM
Glad you found us, Badmetal? Welcome aboard.

I've been hogging the show lately. I'll let others help you with the slate. Hang tight. Someone will be along.

John Bridge
08-09-2001, 07:10 PM
Okay, I'm sure someone is typing a reply right now, but . . .

The slate should be cleaned off with clear water and then allowed to dry if it's as yukkie as you say.

The edges should not be honed down, as it will cause the material to lose some of its character. It's supposed to look rustic, not smooth and polished.

Pre-sealing is a matter of preference. I don't, but you might want to if you're not too experienced in grouting.

Watch. As soon as I post this, there'll already be two replies saying pretty much the same thing. :)

Rob Z
08-09-2001, 07:18 PM
Hello badmetal

I have installaed slate only a few times, and I did preseal a couple of the jobs because the slate was extremely porous. On one job I did, the slate was very "tight", and wasn't a problem to grout .

Can you go through your slate and describe it for us? How consistent is the thickness throughout the batch? How flat are the pieces? Are any of the pieces flaking on the edges or tops?

What are you setting the slate on?


Bud Cline
08-09-2001, 07:25 PM
I don't see much slate around here it's as scarce as saltillo. Installation shouldn't be a major deal except the slates I have worked with in the past have come in two forms. The easiest is the slate tile itself, mor or less uniform in size and more importatntly thickness. If you have the tile uniform in thickness then it's a snap as tile installation goes.

If your tile is in fact pieces of different shape, size and different thickness then you've got your work cut out for you. This is "random cleaved slate" and it requires a lot more thought and a much thicker mud bed for setting.

Before I go nuts here....which is it?

08-11-2001, 05:31 PM
Thanks for the speedy replies! I really didn't expect it, as I would have replied much sooner.
Ok, the slate is all 12 x 12 and is "basicly" all of the same thickness. It's multi color, cartons say made in India, and alot of the tops are flaking. Alot of corners chipped, some broken off.( This stuff appears to have been around awhile, the cartons crumbled in my hands.)
This one is hard to describe..hold a tile up to see its thickness and its split inside. There's afew of those.
Even got some really rusty ones.
Most of the tile lays pretty flat, some of it "rocks".
The slate will be set on a concrete slab that is about seven years old now. It has some thin cracks and alot of chips from where I removed carpet strips. Other than that it's a very flat and smooth surface.
I know that if I can set it, grout it, and seal it using the proper materials and methods, I'll have one outstanding floor.

Rob Z
08-11-2001, 09:33 PM

Get a 1/2" notch trowel, and be ready to backbutter your pieces of slate. For the ones that are not flat, you will want to pull them up periodically to check for coverage. After a while, you start to get a feel for the shape of the pieces and how much material to trowel on the underside.

Depending on how "unflat" these pieces are, you will want to use a medium bed mortar. No big deal, it behaves pretty much like thinset mortar. If Home Depot is your best option for getting material, get Custom's marble and Granite mortar. That is a medium bed mortar, which means that it can be piled up thicker than thinset mortar without loss of strength.

You'll need a wet saw to cut the slate. And avoid those pieces that seem to be breaking into layers.


08-12-2001, 07:48 AM
Hi Rob
I'm about 2 weeks away from starting my slate project and am starting a tool and material list.
Home Depot is an option. I have a Lowes and Ace Hardware close by as well.
I've stained some birch paneling that I need to seal (waiting for the rains to stop) and put up before I get into the floor.
Thanks again

Rob Z
08-12-2001, 09:44 AM

Good luck, and keep us posted.


Bud Cline
08-12-2001, 09:49 AM

Rob has you on your way man, I'd be more concerned about the "cracks" in your slab you mention. Shall we pursue this potential for a failed floor or just skip over it?

The cracks in the slate are natural and you do know this material will more than likely continue to shed wafers from time to time from the way you describe it?

Sounds like these tiles are fairly uniform though. Any tiles that teetor now won't when they are "set" into the thinset. Strive for 100% coverage with your setting bed to tile contact.

Rob Z
08-12-2001, 10:00 AM

If you want to guard against the cracks in the slab causing problems later down the road, you will need to use a crack isolation membrane of some sort.

I use Schluter Ditra most often. I buy it by the roll, and it ends up costing me only about $1.08 per sq foot. There are other products out there that are more expensive and products that are less expensive. That's just the one I like and use the most.

If you're interested, we'll talk you throught that part, as well.


08-12-2001, 10:35 AM
With no more than 150 sf, and no experience grouting, do yourself a favor and pre-seal before grouting. I would also encourage you to go through all 150 sf and do some "culling". Best, Good, Bad piles. Use the worst in terms of fractures/flaking/broken corners for perimeter cuts. If the thickness is realtively uniform, thats one less criteria to worry about when your culling. Be sure you place any domed, warped, twisted, etc. with the "high" corners facing the thinset when you set them. This will reduce lippage throughout the installation. I agree with Rob, use a medium-bed bonding mortar with a larger notch and "bed" each tile well. Tap each one lightly with a rubber mallet after setting and pull and back-butter any tiles that sound "hollow".

If the cracks in the slab are not extensive and/or wide, use a product like Laticrete Blue 92 to isolate individual cracks. Easier, and less expensive, to treat those cracks now.

08-12-2001, 11:53 AM
1 crack thru center of room, settling I'd guess. Fine near exterior wall and gets abit wider, maybe 1/16 as it goes.
I want to do whatever it takes to get it right, so I'll put the isolation material on my list.
With my total lack of experience, presealing the tiles may be a good idea. Any brand recommendations?

08-12-2001, 12:18 PM
Badmetal,(sounds like the music my kids listen to), my favorite sealer for natural stone is Sealer's Choice 15 Gold manufactured by Aqua Mix. You can generally find this at stores like Home Depot. Tile Lab also makes an extensive line of sealers, cleaners, etc and is available at Home Depot too. Some of the sealers appear a little "pricey", but use a good one prior to grouting, and then again about a week after the installation is grouted. This will seal the grout and slate again.

08-19-2001, 12:18 PM
Hi everyone
Got another question about the slate.
I've heard that lengths of 3/8" thick wood should be used for spacing. Can I not use tile spacers and is there a problem with less than 3/8" spaces?

Rob Z
08-19-2001, 12:46 PM
Hi Tony

I don't use spacers for floor installations. Determine what the average size of the tiles is, and what the max plus/minus is, and decide on a grout joint that accomodates this tile.

Let's say you determine that 3/8" makes a good grout joint. You then form a square grid on the floor with chalk lines, with boxes formed for 4 or 9 tiles at a time (2x2, or 3x3).

Once you have a grid that is square and represents the average size of a tile plus grout, you set the tiles within the grid with no need to fool with spacers. this is foolproof, as long as you stay within your grid.

Give us an idea of your tile sizing and variation, and we'll make a guestimate as to what grout spacing will look good. It's probably going to be 1/4" -3/8", though.


08-20-2001, 05:07 AM
Lauderdale tile in Opopka, will have all the materials and tools you will need to make your job sucessfull.

If the slate isn't consistant in thicknes, you may want to consider making a jig, to lay the tile in face down and screed mortar/thin set/medium bed mortar across uniformily.

You would then lay this tile into the combed ridges of the material already in place across the floor.


08-27-2001, 09:29 PM
Sorry I haven't replied sooner. Serious illness in the family has kind of postponed my little project. Rob, the grids sound like a great idea, and I think I'll go with the 3/8 space.
Art, you do mean Apopka....right?

08-27-2001, 09:50 PM
Hey Art,
I use to drive for "Honey Transport" in Apopka way back in '88. Glad I don't no more!!

Rob Z
08-27-2001, 10:31 PM

Sorry to hear that. Hope all is well.

Come see us again when you are ready to go at it again.


03-22-2004, 05:34 PM
Hey Guys! Great Advice, Thanks.

I just had slate tile installed in my living area (14' x 17') - using 3" cuts for the slate border. I didn't use spacers but rather "butted the tile together", leaving little space between them; of course wider at some points than others. Will this make the grouting process more difficult?

Also, I did not clean the "very dirty" tile prior to installation, but I am going to pre-seal before grouting. Should I clean before I seal or is it too late and would it be a waste of time at this point?:bang:

Thanks to all,

03-22-2004, 07:24 PM
Hi Judy, welcome. You should have left 1/8-1/4 joints. Slate normally varies in size too much for a tight joint.
Yes, clean the tiles before sealing. Let it dry out.

03-22-2004, 10:22 PM
Thanks for the reply. Hopefully, the fact that I did not leave enough space between the tiles won't make too much of a difference--considering the fact that I spent a small fortune on the slate.............and it's definitely not going anywhere now -hehe!!! Anyhow, believe it or not, it really looks great (very natural looking) even being "very dirty, without the grout and without the sealer.

I do not look forward to cleaning it, but when I do, I want to do it properly. Do I need to worry about water and/or acid cleaner getting into the seams - since there is no grout yet, or is that what you mean by saying to "let it dry thoroughly"?


03-23-2004, 06:14 AM
If you are talking about plain old earthy dirt, you don't need acid to clean the tiles, just clean water and a scrub brush. Water won't hurt the thinset, but acid will.

Vacuum as much of the dirty water up with a shop vac as you can, so it will not leave a film of dirt to interfere with the grout bond.

03-23-2004, 05:14 PM
Hi Judy, don't put the sealer on wet tiles, let them dry first.

03-24-2004, 06:01 AM
OK, great!!! No guessing what I'll be doing this weekend..........thanks for everything fellows. I'll let you know how it turns out!

So long!

05-13-2004, 02:27 PM
Hi there, it is nice to see that one can exchange ideas and get advice on various subjects. My wife and I are getting ready to install approx 600sf of slate we bought at Home Depot. Golden Florence and it varies dramatically from an almost black grey to a golden sand color passing through some rust orange. The box says is a product form China. We took some of it out and while beautiful, we have seen some serious flaking on some tiles that I'm sure cannot be used. The dimensions seem uniform, 12"x12"x1/2"(excepts those that are flaking, which are thicker). Thinking of all that stone found in commercial/institutional facilities floors with no grout spacing. We were envisioning a groutless slate floor. My first question is: can this kind of slate flooring be installed groutless? A second question: we were thinking on having a pattern develop from having smaller squares mixed with the slate around it in a 45 degree skew pattern. Is slate easy to cut with a small wet table saw? How long do you think it will take us to install the 700 sf floor (contigouos kitchen and family room)?
IWe look forward to your responses.

John Bridge
05-13-2004, 08:04 PM
Welcome aboard, Zorro. :)

You must have grout joints to keep things from collecting between the tiles. You'll find that all the pieces are not exactly the same size, and some of the tiles are not qute sqare.

05-24-2004, 08:41 AM
Is it possible to set slate over vynil linoleum? I had to remove parket floor in one area and it was quite laborious.....It would be so much better if I could install the slate tile directly over the existing floor covering in the kitchen.
I appreciate your input

John Bridge
05-24-2004, 06:22 PM
In a word, no. :)

You must at the very least remove the linoleum, and we don't even know what's under that. How do you know you're floor will support slate?

05-25-2004, 08:11 PM
Sorry, I should've mentioned that the house is on a concrete slab. The kitchen's vynil linoleum is solidly adhered to the concrete. The house is about 16 yrs. old and the concrete slab is in good condition. It's just that I know it'll be a chore to leave the concrete slab free of linoleum and adehesive residues.

05-26-2004, 08:44 AM
It's a chore to remove the vinyl and prep the floor, but it'll be even more of a chore to redo the slate in a couple of years because you didn't do the prep work!

In for a dime, in for a dollar! :D

06-08-2004, 04:30 PM
I just finished installing the same slate a customer bought at
THE HOME DEPOT. I put it in a Shower and on the bath floor
I always butt slate and natural stone with no grout joints
(unless customer prefers joints) Its easier to lay with grout
joints but doesnt look as good with natural stone.most times
Iuse just a sealer but if you want to pull out the color of the slate you can put a stone inhancer on the slate and with and
it will look the same as when the slate is wet.You will definetly need granite and marble mix because Chinese slate is about the worse gauged slate Ive come across.also makesure and lay out of several different cases at once. good luck.

07-08-2004, 03:11 PM
Just wanted to thank everyone who has contributed to this subject. There are posts from back in 2000 and I'm reading them for the first time some 4 years later. So for everyone who has taken the time, thank you!

After reading through all the messages in this topic, I've taken some notes as follows:

Clean/wash dirty slate before installing it.
Let it dry then use a pre-sealer.
Use Aqua Mix or Tile Labs pre-sealer.
Use medium bed mortar (ie for marble and granite) as slate doesn’t have uniform thickness and may be cupped.
Use 3/8” spacing for grout.
Use plastic bag for putting grout in groves.
Use a 1/2" notched trowel.
Butter the back of the slate before setting.
Tap with a rubber mallet.

Ok, I'd like to ask a few questions about my particular situation. I'll be installing 16"x16" slate over concrete. The concrete was pored in sections and no cracks are apparent, however, there will be places where I'll have to put a slate tile over the join between two sections of concrete. Any issues there?

The installation will be for an outdoor patio, and the existing concrete slopes away from the house. Also there are places where 3 sections of concrete meet and the concrete in this area is far from level (in other words, the corners of each slab of concrete are lower creating a depression which holds water). These depressions are maybe up to 1" deep at most. Will the medium bed mortar be able to fill in these depressions? How do I assure that the tiles are then (relatively) level?

Lastly, the patio is a strange shape. One corner is square, but the other three are at various angles (looks something like Plymouth rock laid flat). The square corner is against the house and is about 25’ wide. My plan was to put the slate tiles in starting with a row against the house, then do one row at a time. Would it be better to do the (eg) 3x3 sections, and if so, how do I make sure that the final line that is against the house will be straight? Regarding a chalk line, the concrete was “stamped” when it was pored, so there are 6” hexagonal groves throughout. So it may be hard to get a readable chalk line. I was thinking to use string to align each row.

Thanks again to everyone who has contributed to this forum.

John Bridge
07-08-2004, 06:21 PM
Hi GMoney, Welcome aboard. Stop into the Pro Hangout and tell us who you are and what you do. That way we can take pot shots at you knowing who we're talking to. :D

Welcome, Dshan. Is that your name? :)

There are a couple major things you need to know. First, you cannot cross over the expansion joints between the sections of concrete. You mud leave a joint in the tile directly above the concrete joint. The tile joint will be filled with cauling or flexible expansion joint material, not grout.

Since your depressions are up to an inch deep, you should first do a little smoothing with patching cement or with deck mortar before you begin the tile installation. Get everything to flow before you start. :)

07-09-2004, 02:06 PM
Hi John,

Thanks for your reply. My name is David, but it was already taken.

Could you recommend a brand of patch cement? I have used two different types of cement "floor leveler" products, but am guessing that the "patch" cement that you refer to is a different animal. How deep should I consider is the maximum for the medium bed mortar? Is there a "thick" bed mortar?

The depressions are located where the two sections of concrete meet, along the edges. There is no expansion material in there, the two slabs were just pored abutting each other.

Any tips on the best way to get a good grid pattern? Should I use spacers?

Thanks again,

08-12-2004, 01:45 PM
What a great thread. I've been looking for tips on installing slate tile for a few days now, as I'm starting a 150sf kitchen project tonight. I've read all the threads back to 2000 and got most of my questions answered, but there seems to be some disagreement on a couple of things:

1. Should you butt slate or use grout joints (or does it really matter)? I think butting the tiles looks better, but I want to avoid any problems that might arise. What is grouting going to provide beside keeping stuff out of the seams?
2. Should you use sealer or not? I've heard leaving slate natural is sometimes a better option. Is sealer required?



08-14-2004, 01:15 AM
so, do i understand from earlier postings that inserting grout in joints is easier and more rooky friendly if you use an injection system like a bag with the corner cut our, or a cake icing tool?

John Bridge
08-14-2004, 03:43 PM
Slate and other natural stone tiles should be spaced and grouted. There is no way you can completely close butted tiles, I don't care what anyone says. ;)

Slate looks good with joints up to a quarter inch or so. Use sanded grout in that case. If you do manage to get the joints down to a sixteenth or so, use unsanded grout. And yes, seal the floor after the grout has cured a few days.

The cake decorator idea is tedious. I don't recommend it. I grout with a regular grout float. Do small areas at a time so you won't have problems wiping up the grout. Make sure the area is squeaky clean before moving on to the next. ;)

08-14-2004, 10:21 PM
I am nearly finished setting the backsplashes in my kitchen with what I think is the same product from HD. I've used a mixture of Chinese slate (multicolour) and Indian slate (copper) which I cut down to 6 x 6. Here's my big DIY tip - take your time! Close second is to make sure your saw blade is sharp. That Chinese slate seems to have a lot of iron in it and can wear out those diamond blade quicker than you think. There is a lot less chip out with a sharp blade. Good luck!
Gina in Canada

08-15-2004, 03:34 AM
I just started a 450 sq ft slate project through my house. I've been coached by the boys (and girl) at The Home Depot, and I have a good feel for what I'm doing, but I do have a concern that I hope you guys can help me out with. I find that the variations in tile thickness seem to be rather drastic at times. What are some tricks to be able to keep the top surfaces level? My wife's afraid that those little ledges will become safety hazards.

08-16-2004, 04:53 PM
I'm confused about the sealing. Do you pre-seal before laying the tile itself, or before putting in the grout?

I'm also worried about slate's inherent uneveness. How much of a toe stubber will it be?



John Bridge
08-16-2004, 07:05 PM
Hi All, ;)

Slate is rough on the surface even when an excellent job of installation is performed. You can back butter thin set on the backs of the tiles as you go to help reduce the amount of "lippage" that is always present in a slate tile job. Absolute toe stubbers should be attended to, but there will be a certain amount of uneveness. Get used to it. ;)

On the question of whether to butt the tiles together or whether to leave grout spaces, both the tile and stone industries recommend at least a narrow grout space. The grout has to be able to lock into something, otherwise you'll have a good looking floor for a while, but eventually you'll be repairing the joints. And then, of course, it's a never ending chore. I don't install a lot of slate tile, but when I do I leave approximately a quarter-inch joint between the tiles (it varies, of course), and I use sanded grout. Wider spaces also reduce the abrutness of the "lippage" I spoke of above.

08-17-2004, 08:49 AM
I know you don't like slate, but I have to try it for myself. :twitch: Leaving space for the grout makes perfect sense, as does the type of grout. Thanks for the input.


08-17-2004, 03:44 PM
I'm confused about the sealing. Do you pre-seal before laying the tile itself, or before putting in the grout? Kellen

I was curious about this too... From what was said above, the idea seems to be to seal the slate prior to grouting and once again after the job is done. Sound straight forward enough. However, in for the "prior to grouting" sealing, should that be done on individual tiles prior to setting them in place, or can it be done to the whole floor after all the tiles are placed? :dunce:

I ask because I'm thinking that puting on the sealant with the tiles in place would result in getting sealant between the tiles, which would keep the grout from sticking properly. :bonk:

So maybe the idea would be to wash (in reference to the "dirty tile" episode earlier) the tiles and then seal them individually before starting the job?

John Bridge
08-17-2004, 07:40 PM
I think you'll find that old timers like myself don't pre-seal anything. I see not reason for it. Slate is not overly porous. What makes it hard to grout and clean is the fact that it is clefted on the face and not sawn like it is on the back side. Sealer isn't going to change that one bit.

I do recommend a sealer on the grouted floor. A bit of the product will be absorbed by the stone, and the grout will be sealed in the process.

In answer to your qestion, though. If I were going to pre-seal the stone, I would do the individual tiles, trying to be careful not to let the material run over the edges onto the surfaces that will contact the grout. :)

Oh, and it's not that I don't like slate. I love it. It's just that it's very hard to maintain.

09-03-2004, 07:21 AM
I am getting mixed messages from the local "experts". Is there any reason why slate would not be a good idea in the batroom and/or shower area other than its uneven nature?

John Bridge
09-03-2004, 09:45 AM
How are you going to wipe it off?

09-05-2004, 10:00 PM
I've just finished reading through all the slate entries and have found lots of very useful information--thanks! We're replacing the walkway leading to our house, and our plan is to have regular cement, with a single strip of inset slate tiles every six feet. Here's my question: Should we press the slate right into the cement, or let the cement cure first, then use mortar? (From this site, I get the feeling that mortar is the way to go, but a couple of the Home Depot people I talked to said we could lay the slate directly into the wet cement . . .)



09-05-2004, 10:15 PM
Perhaps I should have asked this question first: Is it a bad idea to use slate at all on a walk that will have to be shoveled for snow? Most of the slate projects I've read about here seem to be interior. How does slate stand up to the weather? (We have hot summers and cold, snowy winters.) We are leaning toward using slate because it is reasonably priced as far as stone goes (the quartzite we looked at cost ten times more than the slate), but if it is going to flake or break away in the winter (even if it is well sealed), maybe that is the reason for the price difference. Suggestions?


John Bridge
09-06-2004, 10:17 AM
Hi Jenny, Welcome aboard. :)

I wouldn't use slate, but that might just be me. One thing for sure, you should not attempt to push it down into the wet concrete. That will make a mess, and it won't hold well to the concrete either. It's better to leave a depression for the stone. You can then install it with thin set mortar when the concrete has dried.

You should start your own thread. You might get lost on this one. :)

09-06-2004, 05:33 PM
Thanks for your reply. Could you tell me why you wouldn't use slate? I followed your advice about posting a new thread, so you're welcome to reply there or here. If you didn't use slate and you still wanted a strip of durable color-contrasting material, what would you use?


09-08-2004, 09:38 PM
Hi All!

Ok slate install has started. Background - 1960's ranch in North Idaho (yes Idaho is in America), removed existing 3/4" oak floors (cost to refinish more than cost of slate, but not by much it turns out :crazy: ), left 15# building paper down, installed 1/2" wonderboard over versabond thinset with more screws than used in all of WWII (so it seems). Next comes the actual slate install, which raises the following questions:

1) Should I use a product like "Grout Easy" from Aldon to assist with the grout removal?
2) The Slate is "Leather" in appearance and we would like to improve upon the color and add a gloss to it - perhaps a little darker. Should we use a stone color enhancer? Acrylic floor sealer/finish? Aldon's SBS or Pourous Stone were suggested.
3) And what about a sealer protector such aas Lifeguard from Aldon? Sounds redundant but...
4) With the weather changing here are there limits to temperture for installation (this is over an insulated crawl space) and what about fumes/off gassing of any of the products I mentioned?

Ok that was a lot but as mentioned in other post it is better to do right once than have the nightmare of having to remove it and start over.

Thanks for any and all answers.

Mike60 :) :shades:

09-08-2004, 09:57 PM
Welcome aboard, Mike. :)

First thing we gotta do is get you to start your own thread. As John mentioned to Jenny just a couple posts above yours, you'll get lost in this antique thread for sure. Start a thread and just copy your post into it, or start a thread with a catchy name and I can move your post over to it. Copy and paste is the easiest, then we can just disappear your post here, eh?

And you do need to be posting here. You're not gonna like the first advice you get, but you'll get it anyway and it'll be both true and accurate. :shades:

09-09-2004, 07:30 AM
Thanks CX. I started a new thread but can not see it yet. I am hoping the news I get is not catastophic. This to date has been a fair amount of work and I am hoping for a successful completion.

09-24-2004, 12:47 AM
Hi All,

Perhaps my confusion is due to the late hour, but I'm seriously considering hauling my slate back to the Lowe's from whence it came. It's from China, multicolor, haven't culled it yet.

If it stays, then we're looking at a 165 sq. ft. job in a sunroom. I'm wondering if the strains of working with such a project could be the undoing of marital harmony however. It sure don't sound easy. I didn't know, either, that slate is hard to maintain.

Oh well, a couple of questions:

In culling, should flaked tiles go in the worst pile?

Since slate is also used outdoors on dirt, then why can't it be filled indoors with commerical sand? Is it only because one can't seal sand or is there more to it than that?
(This may sound crazy, but you're dealing with someone who was previously researching laying an earthen floor instead, so thinking outside of the box and as close to the source as possible is usually my mode.)

I'm planning on using an 8 x 10 area rug over the floor and considering that that doesn't leave a whole lot of exposure for an 11 x 15 room, then would sand be so bad an idea?

Thank you in advance for any advice and experience that you can offer. I need to bookmark this site.


09-24-2004, 06:03 AM
There is a big difference between laying slate pavers on soil outdoors and laying slate tile on sand in the house. Aside from the need of the slate tiles for some very rigid and void-free support, sand will simply not stay where you put it. Maintaining the slate will be the least of your worries.

On a administrative note, please start a new thread for your project, and while you are at it, register. You'll be able to post pictures (we like pichers!) of your project so we can help you better. Also, by posting your own thread, neither you, us, or the owner of this thread will get confused by the cross-talk.

03-05-2005, 04:16 PM
Greetings - I'm new here and in the middle of my kitchen/dining room slate project. Picked up some nice cheap slate at Home Depot - $1.80/ft^2. Lots of variation in the Earth tones. Most tiles are black, some oranges and reds. Question is, should they be laid out randomly or more structured to match and transition the tones?

I prefer the later, but if and when I sell the house, what does the rest of the world prefer?

Many thanks,

05-08-2005, 11:04 PM
Hope this thread is not dead........not much activity in recent years!
My slate is already in place on front porch. 180' sq. I am going to seal before I grout my slate. I read in an old post not to get the sealer in the space between tiles where grout will go. How do you do this and will it really matter? I cant see grout popping out from between tiles. Also would sweeping the tile off or vacuming it be sufficient to rid it of dust before applying the seal. If I hose down the tiles it will be days before it dries out so I can apply the sealer.


07-13-2005, 07:53 PM
John I am in the planning stages of installing about 400 sf of slate tile. In a few of your responses you have mentioned that slate is very hard to maintain. Can you give me more details on this? Thanks

08-13-2005, 09:47 AM
i am installing 800 sq ft of slate tile. first tile install project for me. ever. so far i have laid the pattern out for about 400 sq ft. i used 1/4 spacers and am now getting ready to set it. thank god i found this site. i was thinking about nixing the grouting and just setting the tiles right next to each other with thin-set mortar. both appear to be bad ideas. i am going back to the store to get medium bed marble and grout mortar. i will set using 1/4 inch spacers. after the floor is set i will wash it with water and then seal the floor before grouting. it seems like this is a good idea for rookies because it protects the floor a little from grout? i will then re-seal after i grout.

i have that chinese slate, too, and it's pretty uneven - but it looks cool.

i was going to install over some linoleum in my bathroom (which is over a concrete slab). i have a couple of books that say this will work fine if i sand the linoleum? that's my main question ...

oh ... and i plan to use a sealer that keeps the slate looking as natural as possible ... no shine wanted.

and i am using 1/2 trowels.

this site rules.

08-13-2005, 06:30 PM
Hi Unsearching, welcome. :) How about a name to call you by, don't hafta be your real one.

Let's get a couple things straight, Thinset is used to stick the tiles down, grout is used to fill the joints. These are two different materials. You can use Versabond instead of the granite thinset. It is cheaper. I would skim coat the backs.

I would rather have 3/8 joints myself. The slate is different sized, you'll have a hard time keeping a consistent 1/4 inch joint.

Tile has been installed over vinyl successfully before but is a risky way to install it. Your tile job is only as good as the vinyl job, I'd yank it up, put down a membrane over the slab and sleep better at night. Especially on a little bath floor. :)

08-13-2005, 08:30 PM

Why a membrane? Can't tiles be laid directly over the concrete subfloor or in my case foundation?


08-22-2005, 11:50 AM
my name is brian - just use my band name when isign up for these things b/c brian is usually taken! wish i woulda used 3/8 inch spacing ...

i have laid almost all the tile as follows:
in a diagonol pattern flowing out of a room and into an entry hallway ...
in the main room i have a 3 inch border that i filled with rectangles, triangles, etc ...

i used a thin-set mortar; used the acrylic ad-mix for strength; 1/2 inch trowel; coated the backs of each tile and the floor ... hope this doesn't cause a problem ... too late now); laid the tile directly onto the slab; removed the linoleum ... there wasn't much glue to scrape off ...

so far so good

now i have to grout and seal

so, if i understand this correctly:

i need to mop the slate with water to clean it; let it dry; then:
i think i would like to add some enhancer to bring out all the colors? any recommendations?

and then grout and then seal ...

there are a couple of extreme height variations ... i may remove those tiles and replace them
i had to remove a few misplaced tiles already ... that was not too hard with a chisel and a hammer, but it wasn't easy or clean

the thin set can be hard to get up once completely dried ...

it was also a learning experience creating a tile/carpet boundary; i removed carpet where i put slate ... i found the best solution to be the metal boundary thing that the tiles lay on and the carpet gets tucked under ...

my next step is to lay pergo in the kitchen where the slate ends .... i hope i find the solution to that border more easily than i found the carpet/slate solution (i first used the wood strip with the nails ... i didn't like that .... )



08-22-2005, 06:35 PM
Hi Shannon. Yes it can be installed directly to the slab if there aren't any slab cracks. I've seen very few slabs without cracks somewhere. If the slab isn't new and there are no cracks, go for it. A membrane is cheap insurace. A bucket of Semco is about 130.00 and will cover about 400 sq ft. Replacing a few cracked tiles later on will eat up 130.00 worth of labor real fast. :)

08-30-2005, 09:22 AM
What I've learned to date:

After placing all the slate with a thin set mortar I realized I should've probably taken more time to pick and choose pieces more carefully. I do have a few 'lips' that I think I could've avoided ....

Also, I think I may have used a little too much thin-set, as I coated the floor and the back of each tile with a 1/2 trowel ...

I did use some additive to the thin-set to strengthen the bond, and I think it helped, b/c I had to remove a few pieces after they were set for about a week, and it was much more difficult than my other tile-removing experiences.

I used a grout bag to fill the grooves and I smoothed the grout with my hands. I am in the process of cleaning the grout haze now. I bought some Aquamix grout haze cleaner, so I hope that helps with the process.

Once the floor is clean I will seal with an Aquamix enhancer/sealer. I hope the enhancer keeps the stone looking almost wet -- that way the colors will stand out more.

I will have spent about 10 full days on this job - for about 600 sq ft of slate.

08-30-2005, 08:21 PM
Hi Brian :)

Use caution if you need to use the grout haze remover. It is acidic, and not recommended for use on natural stone.

07-20-2006, 08:06 PM
Useful thread - thanks guys.

Received a shipment of 200sft of rustic looking Chinese slate from manufacturer, and we had about 50% loss on each box of tile. I have heard that 10% should be expected and about 15% is the max acceptable. When the tile was cleaned, we could tell that the manufacturer had actually GLUED some broken tiles back together and then shipped them.....LOTS of them. Needless to say I had the manufacturer come over and take a look and they said that in 15 or so years in the business they had never seen anything like this and are having to replace the slate with a different lot from the manufacturer. We will see if the next batch is the same...

Anyone seen this?

Also what is the downside to using slate in the shower?



Jennifer M-A
01-02-2007, 04:31 PM
Hi All,
I hope that this thread is not dead... I've read it all. I have some questions that I don't know if they were answered and I just missed them. I currently have beautiful multi-color slate in a bathroom and shower. I received so many complements on it that my husband and I decided that we want it in our master bath and shower, sun room and entryway. I love the earthy look of it. The guys who installed it in the first bathroom did not clean it before installing it.... what a pain in the butt to clean it before sealing so I do reccommend washing before laying it. Presealing (before grouting) would have probably helped too. It still turned out gorgeous though. I could attach a photo on th next thread.

Anyway, I am making a cheat sheet for the new guys that will be installing it to get it 'right'. (just in case my contractors aren't that experienced with slate)

Wash before installing
Pre-seal before grouting
3/8" spacing
medium thinset

My husband is picking all 500+ Sq Ft of it this Friday.
Should I just begin washing the pieces and separating them myself by quality(culling)?

John mentioned that slate is hard to maintain, why do you say that?
Please, I am nervous now not knowing why you would say this.


03-21-2007, 12:08 PM
I too hope this is not dead,

This forum has really been helpful with what I have done so far. I have all of the tile installed and ready for grout. It looks great. I could not have imagined it would look so good. Now I don't want to screw it up with a poor grout job. I have grouted regular tile before and I'm not worried about doing it, however I am worried about cleaning the cleaning the grout off rought slate. I have read about the pros and cons of presealing and will probably do that. I still want to know the best process of cleaning the grout off the tiles. Please someone let me learn from what worked or did not work for you.


03-21-2007, 03:07 PM
hunter, i get more slate jobs than I expect and have tried presealing and not presealing. save a few dollars on the preseal. use two buckets at least, change water frequently, and get the areas nice and clean before moving on. just work one small space at a time - 9-10 ftsq maybe. the next day you should see light haze, but buff it with a dry rag and it should come right off. seal it all in a week or so. brent

03-21-2007, 05:32 PM
Hi, when it comes to grouting, use a grout gun, it will save you hours in cleaning up afterwards. :wave:

03-21-2007, 07:31 PM
Tony, LD is right, We do a huge amount of slate and the nicest thing we have done for ourselves is to pre-seal before grouting. Keep it clean while you are setting it also helps a lot, it's all the little ridges in slate that are a pain to clean. Work with a sponge and clean water while laying.

We don't use spacers at all. We lay it out and get a measurement of the size we want, often 12 1/16" and then snap a grid on the floor, ususally a 24 1/8" grid (4 tiles).
Good luck, Michael

03-22-2007, 10:24 AM
Thanks for the ideas. What's a grout gun? I have never heard of or seen one but I am picturing something like a caulk gun that you can fill with grout. Is there such a thing?

03-26-2007, 08:51 AM
I am about to start a slate job on my patio. I had a patio extension done between my house and the existing patio. The new concrete was doweled in on three side attaching it to the orginal house foundation. My questions is can I tile over the area where the new and old concrete exist if I use a membrane?


03-26-2007, 05:29 PM
Hi jmcl, Welcome!

Feel free to start a new thread for your project. We are also on a first name basis around here, so feel free to share yours (or even put it in your signature line).

Does the new and old concrete meet at a door way, or the entire width of the slab? :shades:

Shrinkage will be absorbed in a membrane, but it will not help vertical movement. Some type of a soft joint may need to be implemented as well.

03-27-2007, 08:17 AM
Thanks for the quick reply. I have attached a picture of my patio. The original patio was poured and is part of the original house foundation. The patio extension has been doweled in at the original patio, at the windows, and the far wall. You can also see a small 24 in area that has been doweled to the old patio. Can I tile over this joint if I use a membrane? I wanted to lay the tile in a staggered position, which would require me to go over the joint.


Kelly K
04-29-2007, 02:56 PM
My husband and I just installed slate tile in our bathroom. After he put the grout in and it dried we have been scrubbing and scrubbing to get the black residue off the tile and it is not coming off. Does anyone have any suggestions for a better way to get this stuff up- or when we seal it will it not show? Thanks

06-12-2007, 02:02 PM
I am geting ready to install gauged slate 12x12 tiles from india on my Advantech flooring. I already have warm-up loose wire electric heat laid. Should I have used a backerboard or will it be okay?

Brian in San Diego
06-12-2007, 02:12 PM

Two first things...start your own thread for your project (then you can ask as many questions as you want and we have a record of what's been asked and answered) and give us a first name to call you.

I would stop right where you are. We need to have some more information before proper advice can be given. First of all, laying stone on a single layer of plywood doesn't meet TCNA guidelines. So, before you go much further we need to know the joist composition, spacing and span. Check the Deflecto on the dark blue toolbar above.

Also we want to know about your floor warming installation. Who is the manufacturer?


06-12-2007, 02:26 PM
I've never done this before so I don't know how to start my own thread. I just replied to this one since I am installing slate.
My joists are 16"O.C., they are engineered I beams, My flooring is Advantech T&G engineered flooring. The floor heat as I said is Warm-Up loose wire system.

Brian in San Diego
06-12-2007, 02:39 PM

Go back to the Tile Forum/Advice Board page. Just above the yellow bar, you'll see a "New Thread" button. Click on it and you'll see a similar page to the one you saw when you clicked on "post reply". The only difference on the "post thread" page is that you must have a title. That title will be the title of your thread for all eternity, so make it something that reflects your entire project. Then once you start asking questions and getting answers your thread will go to the top of the queue.

If you would why don't you give that a try and start with your last question and we'll see what happens from there. I know one thing that you will be you have the manufacturer and the exact numbers printed on the engineered joists. The Deflecto cannot be used for engineered joists.


09-22-2007, 09:35 PM
Hi, I am installing slate to cover an existing concrete slab. I have read this entire thread. Very informative friendly advice. When this concrete was installed before we bought the house, it was sloped towards the house. How do I remedy this situation when I lay the slate? Many thanks.


09-22-2007, 09:54 PM
Welcome, Diane. :)

Please start a new thread for your project. Your questions will get lost or confused in here.

Look at the post immediately above yours if you're not sure how to do that.

09-26-2007, 08:14 AM
Hi all. I just wanted you all to know of a place in Houston Texas called Caliber Tile and Stones. I am about to purchase Slate from them. I have shopped for a while now and they have the best in qyality and price. There stones dont flake and have excellent color variations. Based on replies to my previous questions in this forums they have advised me On my project really well. They claim to be Slate Specialists....they are very helpfull when it comes to advice on slate and have really nice displays.

They recommended a sealer called Jasco..does anybody know where i can get it?