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Need "Primer" on doing slate tile install

Post in 'DIY and General non-hearth advice' started by Gooserider, Sep 8, 2007.

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  1. Gooserider

    Gooserider Mod Emeritus

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    As many of you know, I'm working towards replacing the old smoke dragon that we've been using for our primary heater with a newer stove. One part of the change is that the old stove was side load only, and the existing hearth isn't deep enough to meet clearance requirements for a new stove with a front loading door, therefore I need to extend the existing hearth in some way.

    The old hearth is brick, raised one brick edge above the floor level - it runs diagonally across one corner of the living room. In order not to lose any more useable floor space, I want to make the extension flush with the floor, currently I'm planning to cut the carpet back, remove the particle board flooring and replace it with cement board (I don't think I need to touch the decking under the particle board) and then cover that with non-combustibles.
    The stove manual calls for "1/4" non-asbestos mineral board or equivalent" so this should be plenty. It looks like we will end up needing to make a strip about 18" wide and about 12' long

    There is an entryway next to the hearth that has been finished with a natural slate tile in various colors and sizes in an interlocking semi-random pattern. The GF and I are of the opinion that trying to do a similar slate covering on the extension will make the most visual sense. We think we have a couple sources for suitable material, and I'm thinking I'd like to do the job myself rather than spend the large minimum cost our local floor shop charges to do an install. (it would probably be 2-3x the material...) However I've never done a tile job before, and I need a bit of a primer -

    1. What materials do I need?

    2. What tools are needed?

    3. What is the procedure?

    (If it's involved, pointers to other "how to" writeups might also be useful...)

    Thanks,

    Gooserider

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  2. nshif

    nshif New Member

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    Ok sense no one else has responded to this Ill give it a start.
    Is this tile or real slate ( like 1" thick )
    Are you going to tie into the existing tile?
    How much Sq feet are you adding?
    Tile is really easy to set and only requires a few tools, most of which are cheap unless you need to cut alot of tiles but wet saws are rentable.
    What are the size of tiles you will be working with?
    It really is a DIY project in most cases and not that difficult.
  3. Hogwildz

    Hogwildz Minister of Fire

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  4. Hogwildz

    Hogwildz Minister of Fire

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    And yes its straight, the camera angle makes it look otherwise, I assure you ALL its straight! :)
  5. rmcfall

    rmcfall Feeling the Heat

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    I've installed both natural stone tiles such as slate and ceramic tiles on a couple different occasions. I am by no means an expert, but here are some pointers regarding materials and install tips...

    For materials, you will need a trowell, float, tile spacers, 5 gallon buck and a mixer attachment for your drill, a cement/grout tub for after the thinset and grout are mixed, and of course bags of adhesive and grout. You can get all this stuff at Home Depot or Lowes. You will also want to pick up some sealer to apply to your slate BEFORE you apply the grout. You don't need to do this with ceramic tile, but will natural stone it is an important step.

    I recall that when I redid my previous hearth with slate tiles I specifically used thinset adhesive (which you mix yourself) instead of the mastic that comes in a tub. I cannot remember exactly why I did this, but I seem to remember that the adhesive I used had either a latex or epoxy additive to increase flexibility. I also opted to use either an epoxy or latex grout (I can't remember which) because I was also concerned about having increased plasticity within the grout to avoid cracking. I hadn't used these additives on prior occasions, but I guess I was concerned about the weight of the woodstove, constant setting of firewood on the hearth, etc.

    Anyway, use your drill and mixer attachment to mix up your thinset. Apply the thinset to the cement board with your trowel, then set your tiles by pressing on them firmly. Use your spacers to keep the spacing between tiles correct. You can also use your trowel to "butter" your tile and then set it in place. With a fireplace install, you will need to build some sort of frame to support the tiles above the fireplace opening, as the thinset doesn't have enough grab to prevent the tiles from sagging. After the thinset has hardened, be sure to apply the sealer to the tiles BEFORE applying the grout. If you prefer, you could also apply the sealer to the tiles before adhering them to the cement board. The next step is to mix and apply the grout, but first don't forget to remove your tile spacers. Mix your grout to about the consistency of cake icing or real creamy peanut butter and use your float to apply the grout diagonaly across the grout lines. As you work, use some damp bath towels to wipe the excess grout off the tiles. Just run the towel lightly across the tiles at a diagonal to clean up any excess and be careful not to press into any your grout lines. You shouldn't have much to wipe up, as most of it will have been cleaned up with your float. Allow the grout to cure for the next few days and mist it with water to keep it moist. Clean the haze off your tiles by using a CLEAN towel and some water and perhaps some grout haze remover. Lastly, seal your grout lines and apply more sealer to your slate if you want. I chose to use a matte finish sealer that gave my slate tiles a bit of a wet look without being too glossy. Remember, whatever you do, SEAL your tiles before applying your grout.

    Here's a link to some good information...

    http://johnbridge.com/vbulletin/index.php

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  6. rmcfall

    rmcfall Feeling the Heat

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    I forgot to mention that you will also want to use a wet saw. If you have only a few cuts to do you can get away with using a diamond blade on a grinder, but be extremely careful.
  7. Gooserider

    Gooserider Mod Emeritus

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    Thanks Hogz, not sure I need that much protection, so I'll probably skip the Micore, as I don't really want to have to remove the subfloor decking, but I really want to keep the extension flush with the existing floor. I'm assuming that the slate plus thinset is about equal to effective thickness of the carpet plus pad - it's really hard to measure that, but it feels about right. The existing floor is board decking over the joists, covered by 1/2" particle board, and the carpet. Assuming I don't remove the subfloor, replacing the particle board gives me 1/2" to play with.

    The existing hearth has a front edge made of red common bricks on edge (3.25" thick on .75" of mortar) the remainder is bricks laying flat (2.25" ? thick) I've done a little bit of drilling on the floor just in front of the hearth, and it looks like the edge bricks are sitting on a thin layer of concrete over the subfloor decking. I'm guessing the bricks on the interior (where the stove will be sitting) are probably either two bricks thick or sitting on a thicker concrete bed, but I haven't done drilling to prove it...

    - per my "Hearth Construction" Wiki article, 4" of brick gives an R-value of 0.8, 2.25" of brick plus a couple inches of concrete (@ 0.95 / inch)would be around 2.3. As mentioned in my OP, the stove manual calls for '1/4” non-asbestos mineral board or equivalent' I don't have an entry for that, but I'm assuming they are talking about Durock or equivalent - (What else?) - which would have an R-value of about 0.1 or 0.13, depending on brand.

    Replacing the 1/2" particle board with Durock would give me a value of 0.26, plus a bit for the slate tiles, or twice the manual spec. In addition, there would be the approximately 3" of additional air space provided by the step from the hearth level down to the extension level, further aided by my very rough guesstimation of where the stove will end up on the hearth leaving about 6-12" of space between the stove front and the edge of the hearth. While the manual doesn't give me a spec for how much added value it would give me for this, I figure I should be pretty thoroughly exceeding all the specs, with a good margin for any stove that would fit in the space if I were to ever do an upgrade.

    Otherwise the rest of what you say sounds like something I can handle. The slate I'll be using looks like it comes in about a 1/4" thickness as tiles of mixed sizes and colors (it is natural stone). One thing that I am noticing though is that the existing floor is made up of sizes down to about 2.5" on a side, up to about 12" x 12" - the new tiles only come in about 3-4 sizes, and I was wondering if it would work to cut the tiles smaller and have cut edges in the middle of the floor? I know that doesn't work with ceramic tiles because of the edge shape and the glaze, but what about slate? It should be the same color all the way through, so what does the factory edge give that I don't give with a wet saw? (I'm figuring on buying one of the cheapo HF saws - should last for a one shot job...)

    Gooserider
  8. Gooserider

    Gooserider Mod Emeritus

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    It is a slate "tile" made from real slate stone, 1/4" thick
    Yes on one end - this is one reason for the choice, we don't want to add more materials to the space.
    Its a strip in front of the hearth - the hearth runs a diagonal across a corner of the room, so the result will be a trapezoid shape with the hearth on one side and the rug on the long edge, one angled end will be the existing tiled entry way, the other will be the wall. The hearth is about 12' across the front edge, so I'm calculating between 18 and 20 square feet.
    The tiles come in different sizes - and I may want to cut some smaller to fit the existing pattern sizes. I was thinking of purchasing one of the cheapo HF wet saws - cost is about the same as a rental and I don't have to worry about returning it on the same day...

    Gooserider
  9. nshif

    nshif New Member

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    For a job of that size the cheapo HF saw should work fine. It will be slow though and dont expect much life left in the blade when you are done. I did the same for a small job I did but when I got up to around 800 sq ft I broke down and bought an 8" MK
  10. Hogwildz

    Hogwildz Minister of Fire

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    I didn't remove my decking either. Just took of carpet & padding down to the plywood. It does sit about 1/4" higher than the carpet though. The slate I bought was 1/2" thick, but keep in mind the slate does vary in thickness a little bit from pc to pc. The slate does soak up alot of heat. I originally went with a Layer of 1/2 Durock, but when I felt how hot those slates got, I tore it up and redid with Micore added. Ah just read your going with varied sizes. If the slates are only 1/4" thick, and your asking about the beveled edges I take it? When I used to do slate roofs, I used a hand slate cutter, looked almost like a paper cutter, sept thicker blade. If you can find one of these, it may work well for you to cut & as it cuts, it adds a bevel tot eh edge. I'm trying to remember, but I think if you cut it face down, it gives you the bevel on the face. The top of the cut side is straight. Might work, I used it on anywhere from 1/4" slate to 3/4" slate. Good luck.


    Gooserider
  11. struggle

    struggle Minister of Fire

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    Maybe this does not apply? But here is my concern for this project from my experience in putting ceramic floor tile down.

    You have to meet a required minimum sub floor thickness when putting any type of tile down on a wood style floor joist set up. It seems to me it was including the floor decking you need a total of 1 1/4" thickness and that is determinded from already having a solid joist set up. If you are to walk on it and do not have this thickness met then the tile/slate can flex and pop and or crack as the floor moves in its natural way as house settle etc.

    If this is wrong I am sure someone will chime in.
  12. Gooserider

    Gooserider Mod Emeritus

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    OK, did some serious shopping @ Home Despot this afternoon, got most of what you suggested, except they didn't have Durock, but some other US Gypsum product they said was equivalent - I'll need to look it up tomorrow to verify the specs. I'm planning to add a layer of flashing under the cement board, it won't run the full length but will be way more than the "protected area" needs to be. I'm going for a different source on the tile and grout.

    I did run into some confusion - You reccomended a 3/16" x 5/32" V-notch trowel - all the stuff on the HD displays, the tools, etc. along with the "apron guy" said that size was only supposed to be for wall tiles, and that I should be using a 1/4" x 3/8" x 1/4" square notch trowel for floor stuff - I have a wall project in the future, so I purchased both and figured I'd ask when I got home - @ $3.00 each, I figured it wasn't a big deal... So why are you suggesting that size of trowel???

    The tiling guy also said one should cement the backer board down to the decking, in addition to the screws - any opinions on that idea?

    Looking at the edges on the existing slates is a bit tricky because of the grout, but they seem pretty square, just like they were "broken over" a little bit, like taking the edge off the corners when you cut a peice of metal. What I was thinking of getting to cut the slates was one of these HF Wet Saws Not a "pro-grade" tool, but seems like it would be cheaper than renting and for the little use I'd be giving it...

    I'm thinking the tiles shouldn't get that hot as the stove will be sitting back quite a ways from them, and they will be a little over three inches lower than the surface of the main hearth - I'm attaching some pictures of my existing setup and a sketch of what I'm after

    There is a shot of the way the hearth and the current entryway with the slate I'm trying to match interact, A couple closer shots of the entry way slates, a shot of the hearth (with a bunch of my junk on it :red: ) and a sketch of what the product will look like.

    Gooserider

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  13. Gooserider

    Gooserider Mod Emeritus

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    Well, I'm glad I started doing some more research on the backer board I purchased yesterday! Turns out to not be at all suitable for the application...

    The product was National Gypsum PermaBase Cement Board

    The label says it is UL Classified "Cementitious Backer Units Fire Resistance Classification See UL Directory of Products Certified For Canada and UL Fire Resistance Directory File R22158 Control No. 31LU" So I thought it would be suitable, but I wanted to confirm the R-value and be really certain it would work.

    If you download the Product literature PDF file on it, you will find a mention that it has an R-value of 0.2 for the 1/2" thickness, which isn't as good as Durock, but not bad... However I then noticed a blurb saying it "Should not be exposed to temps over 220*F (105*C) While that temp is more than the material should ever be exposed to on a hearth, it did seem awfully low... Also looking through the applications and instructions shown, the only reference to heat or fire resistance was in the instructions for using it in making 1 and 2 hour fire resistant wall assemblies.

    So I called the National Gypsum Tech support line, and found that according to them the product has expanded polystyrene beads in it, and as a result is NOT classified as a "non-combustible" :exclaim:

    Now I have to either bring it back to HD, or use it in a different project, and I think I'm now going to go find someplace that carries DUROCK and not some other half-ashed substitute...

    Gooserider
  14. Hogwildz

    Hogwildz Minister of Fire

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  15. Gooserider

    Gooserider Mod Emeritus

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    Well, I got two 3x5 sheets of 1/2" Durock at Lowes on Sunday (9.85 /sheet) - had to make them get a fresh pallet down from the racks as the display pallet was forklift crunched. Today I cut out the carpet and then used a cheap carbide blade on my circ saw to cut the particle board, and lifted that. Found when I tried to drop the strip of Durock in, that I hadn't cut the carpet and particle board back QUITE far enough. One good thing about cheapo blades from HF is that the occasional nail doesn't seem to bother them much, and no big deal if it did...

    Now that I can see the subfloor, it is pretty obvious that the existing hearth is bricks on a concrete bed over the subfloor deck boards. - per the chart, that would be about R-0.8, maybe a bit more - my extension will only be about R-0.27, but I found official Durock documentation saying that it was the equivalent of 3/8" millboard when used as a floor protector - they have a specific "Submittal Sheet" on using it for wall shields and floor protectors! Since the Encore manual only requires 1/4" non-asbestos mineral board, I should be well over the requirements.

    I found the deck boards under the particle board were not perfectly flat, and had some gaps up to about 1/2" between them - how much of an issue is this, and is there a reccomended fix?

    Is the thinset I'm using (Omnigrip Tile adhesive) suitable for filling the crack between the bricks and the durock? For use in taping the seams between the peices? Filling in any cracks or voids? If not, what should I use?

    The Durock has a textured side and a smooth side - which side should be up?

    Gooserider
  16. Hogwildz

    Hogwildz Minister of Fire

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  17. elkimmeg

    elkimmeg Guest

    What I would have done is lay out the area in your garage 3/5 or what ever the area is then try to lay down the slate and form your pattern. Then you have an exact size maybe without one cut

    Then measure the tile pattern now you have established the area needed . At that point take a digital photo of your pattern layout then pick up each tile and label its position with a scripto marker. No latex grout should be uses or latex aditives ,because it is combustible use plain water to mix the thin set.

    What I'm saying let the tile patern determine the area not the area adjusted to the tile
  18. Gooserider

    Gooserider Mod Emeritus

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    I am only using ONE layer of Durock - I removed the 1/2" particle board subfloor, and am replacing it with one layer of 1/2" Durock. The reason I purchased two sheets is the size of the area - If you look at the hearth pix above, you will notice that it spans one corner of the room - the edge of the bricks is about 11'6" long. What I am doing is running the extension across the entire front of the hearth, 18" wide so that I end up with a trapezoid shape, about 11'6" on the hearth side and 14' 6" on the room side. Since the Durock is in 3x5 sheets, I need one and a half sheets to make the distance. I am planning my cuts so that the cut edge of the Durock goes up against the bricks (which are a bit irregular, so there ARE some gaps) and so that there will be a 5' length directly in front of the stove, putting the seams away from the stove. I also have a strip of aluminum flashing 10' long by 18" wide that I'm planning to put under the Durock.

    The slate will go over the Durock. I've done a bit of a test run with some left over 1/4" ceramic tile from our bathroom floor, and w/o any added thickness from the adhesives and what not, it's just a little thinner than the rug, with two layers of Durock it's much higher. Figuring that I'll get a little more thickness from the thinset, plus the fact that the slate is supposed to be a little thicker than the tiles, this should be a good combo.

    As to the tape, the Durock install instructions on building a floor protector say to tape the seams before tiling, and I was planning to do what the instructions said...

    Right now my plans are to spread a very thin layer of the tile adhesive - it's the "1 Gallon of Omni Grip Maximum Strength Adhesive, 2 set, ready to use" that you recomended - on the floor, lay the flashing on that, give it another thin layer of adhesive over the flashing, and then screw everything down with the Durock screws.

    Elk, I'm going to have to cut the slates no matter what, as the slate that comes in the box doesn't have the same sizes as the floor that I'm trying to match, so it's not going to be a big issue to make the pattern fit the area - see the tile pics above - I've been taking pictures as I go along, hope to get them up soon, but for some reason my box has decided it doesn't want to mount my camera flash card, and I need to fix that so I can download the camera. Figure that will also be good to show the FD when they come for the inspection.

    Incedentally, the DUROCK official instructions on making a UL floor protector specifically SAY to use "Latex-fortified portland cement mortar" to glue the board down with, and for filling and taping the seams - Does this count as a "manufacturer listing"?

    Gooserider
  19. Hogwildz

    Hogwildz Minister of Fire

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    The Onmi grip worked very well on my hearth extension, I did use regular cement grout though. It was the only stuff I could find in the charcoal color I wanted.
    I used a matte finish on the slates, and it still appears pretty glossy. I am used to it now, but I was expecting much more subtle finish. It did bring out the colors of the slate well though. So in the end it looks better than before I started.
    You pretty much got it now Goose. Now its just getting it done.
  20. Gooserider

    Gooserider Mod Emeritus

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    Well I called the Omni-Grip cement folks earlier today, and they said it was NOT the right stuff to use - they said it didn't meet the ANSI specst that Durock called out in their PDF on building floor protectors. The Omni-Grip was intended for waterproof area application such as bathroom shower tiles and the like. They said it wasn't intended to deal with the expansion and contraction involved in a hearth that's getting heat off the stove.

    They said I should be using "Flex-grip" instead, apparently this is a latex-modified thinset - the same thing that Durock reccomended.

    I've now gotten the Durock cut into place, took a bit of "shaving" the edge of the floor cutout with the circular saw to make it fit, but the cutting and fitting is done - Tomorrow I take the Omni-Grip and the Perma-base back to HD and get some Flex-Grip cement, or some other stuff that meets the reccomended ANSI 118.1 or 118.4 specs. and glue /screw the Durock down. At that point I'll be ready to put the stove in, as the basic protector will be there, the slates are less of a rush.

    However I have a problem in one area that I'm not sure how best to handle. As you may have noticed from the photos I posted earlier, I am tying the slates into an existing area of slate flooring at the entryway on one end of the hearth. It turns out that they apparently only used 1/4" ply under that part of the flooring, and the difference was hidden by the carpet. Now that I have the Durock in place, I'm finding that I have a slight level change at the point where the two floor areas come together - between 3/16" and 1/4" or so. What is the best way to minimize this difference? I've had a few thoughts, don't know if any of them would work or not...

    1. Use a belt sander to taper the last 5-6" of the Durock peice down to a thinner thickness - the area in question is far enough from the actual stove for the R-value reduction to be a non-issue, but I wasn't sure if the removal of the mesh from the top side of the Durock would damage it's structural integrety to much...

    2. Use the belt sander to try and take some of the material off the slate and make it thinner....

    3. Leave an extra wide gap between the two levels of the floor and try to fill it in with sloped grout

    4. Ignore it, and hope nobody ever catches a toe on the step and trips...

    5. ????

    I know that I can't make the difference go away, but I'm hoping that there will be some way to make it less noticeable.

    Gooserider
  21. dmt5000

    dmt5000 New Member

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    I have built a hearth board that is finished with a matte ceramic tile, similar to quarry tile. Does anyone know a good clear finish that can be applied to the tile surface that will stand up to stove heat over time? Thanks,
  22. Gooserider

    Gooserider Mod Emeritus

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    I haven't seen anything specifically mentioned, but I would just go for one of the various stone sealers sold for the purpose - for instance Tile Lab brand. At least that is my current plan. :coolsmile: Apply according to the directions, and let dry thoroughly before firing the stove. Probably you should not use a silicone or acrylic "floor wax" type product.

    Gooserider
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