Replies

1. 
   Guest_ | Mar 30, 1999 07:24am | #1

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   Joe,

   I don't think you're going about this right. This is the front entry to your home, it has to be done right, wouldn't you agree?

   Call in a couple of pros and get several estimates and contract the work to the one that you feel most comfortable with.

   Grouting is cleaned off BEFORE the grout dries and you have to know how. You DO NOT USE any acids in your house, especially if you've never handled this stuff before!

1. 
   Guest_ | Mar 30, 1999 09:47am | #2

   *We used slate on our porch just to have something different. Concrete board is not required to set the slate, and you can use construction adhesive to glue it down. Probably unnecessary this way to remove every bit of what sounds like well-adhered adhesive residue. If you use glue, don't use Liquid Nails, the stuff is evil. PL for one is much more pleasant to work with and stronger. Our substrate was 3/4" pt ply over 4' joists 12" oc, quite stiff. Not sure exactly how much stiffness is required to prevent tile cracking when, say, that new refrigerator is delivered. think I'll send them around back.Transition should be handled with ordinary threshold/transition strip. Don't bother bringing the wood floor flush -- a 1/4" is nothing. The slate is susceptible to chipping and so you shouldn't leave the edge exposed, nor should you set up a tripping hazard.As Gabe points out, unless you are confident about this you may wish to contract it out. It's not rocket science, but does require patience and precision. If you mess up the layout it will irritate you every time you come home. Oh yeah, work hard and promptly to clean off the grout residue -- it is harder with the rough surface of the slate. A damp sponge is all you need.Careful, the slate will be slippery when wet. A sealer is not necessary; it will give that permanent "wet look" that some prefer. Talk to your rock supplier for more info. The generic home improvement store slate, incidentally, is inferior grade to that from a decent masonry supply.Good luck!

2. 
   Gary_M | Mar 30, 1999 04:47pm | #3

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   Hi,

   1st, any sanded grout will be fine, preferably a latex modified grout, dark color like grey is best. Also, there's a release agent specifically made for grouting slate, terra cotta, and such. It's applied before grouting, afterwards when the grout has been applied, screeded and allowed to cure a couple of days, the release agent and the grout will wash out with VERY HOT water.
   2nd, transition piece, metal or wood is the way to go.
   3rd, Slate looks better with a sealer, IMHO. Caution- many contain Xylene and other nasty stuff, use a respirator. Whatever you do, don't use boiled linseed oil, your house will stink for weeks!
   Good luck.
   G*

3. 
   Guest_ | Mar 30, 1999 08:52pm | #4

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   Hi Joe,
   We have 400 sq ft of purple slate on a slab as a passive solar collector in our house. It's not all that hard to DIY. Some things we learned from specialists in slate installation:

   1. Slate tiles are not exactly dimensional. Don't use standard spacers, you have to fudge a bit in layout to make it look good.

   2. Sanded grout works fine. A grout release is very important, we used a product by Aquamix that is wiped on and allowed to dry. Grout as usual, wash down, and as soon as the grout has set up, keep washing with water till the water is fairly clear. The next day wash again with water. No need for acid wash.

   3. Seal with a penetrating sealer. Pay the $ for a good one (30-50$. qt.) (We used 2 qts for 400 sq ft.) Aquamix makes several (We used their 'stone enhancer') which has a wet look for a couple of weeks, but evolves to a nice buff. This is a really important step for keeping the slate clean and stain free. DONT wax or poly slate, it'll turn into a neverending job.

   4. You can buy slate direct from the quary in VT. search the web for Vermont+Slate to find out more.

   As others have suggested, hire a pro if your unsure of your abilities. Good Luck!

4. 
   SteveM_ | Apr 01, 1999 12:21am | #5

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   Hi Joe.

   I have installed slate a few time and always successfully. A solid base is very important as it would be with ceramic tile. Min 1 1/4 " of solid plywood or equivilant screwed down in a very tight pattern. We lay our slate in a bed of thin set and usually use a 1/4 x 1/4 trowel but I have had to use 1/4 x 3/8 . Slate is pourous so make sure your thin set isn't too stiff. 24 hrs later we use a modified, sanded floor grout, usually natural grey, ( your discretion ) and apply it same as ceramic. Do relatively small are's and wipe with a high quality sponge diagonally, ONE wipe with side one of the sponge ONE wipe with the other side of the sponge, then clean the sponge and continue. Plenty of care is needed to be sure you remove all the grout from the face of the slate. Ate the top of the stairs I would use a wood nosing built up to be flush with the slate and I would use all my ingenuity to make the section abutting wood flooring flush. Lastly, slate is not true in size or thickness. It will require a good eye to adjust for spacing and the thickness problem is something you just live with unless you want to take endless hours building up under thinner tiles to keep it perfect. Slate CAN be cut with a hand grinder and a diamond wheel but a wet saw is preferable.

   I havn't tried the Aquamix type produts so I can't comment but the enhancer is worth it's weight in gold.

5. 
   Guest_ | Apr 01, 1999 10:02am | #6

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   Okay, so this is an interior floor. Put down your backer board. Use an acrylic modified thinset for this. For setting green slate, use acrylic modified thinset. Spread the thinset on the backerboard AND backbutter the tiles. As pointed out by others, slate is not square, nor is it "gauged" to the same thickness. You'll go through lots of thinset, so figure 70-80 sf/50# bag of thinset. Slate is not flat on the back and you want 100% coverage. You do not have to backbutter, but remember, I told you so.

   Forget using spacers. Snap out a grid of chalklines after determining layout. Don't forget to include a 1/4" grout joint in determining the size of the grid. (Example: if the tiles are 11 3/4" then the grid should be measured in units of 12". So, a grid would be 36x36" for nine tiles.)

   To start setting in a grid, one tile goes on two intersecting lines. Remember that. When setting, no matter what you do, stay on your lines.

   As for finishing at stair tread, have you thought about tiling down the first riser? If not that, then go with wood nosing as mentioned.

   For threshold, why not bevel the last couple of inches down to the wood floor?

   For grouting, please tell me you haven't grouted before asking these questions. (Believe me, it has happened before.) When grouting, be methodical and consistent. (Do it right and you only have to do it once.) Smear the grout in areas no more than 20 sf. before wiping with wet sponge. Use circular motion keeping sponge flat to tiles for first wipe. Rinse sponge frequently. This evens out the joint.

   Second wipe is diagonal to grout joint. Your goal here is to remove excess grout from tile, so you don't need to apply much pressure. Keep your sponge clean by rinsing frequently. I use 5 gallon buckets of water. Have several buckets of clean water ready so you don't have to stop grouting/wiping to fill a new bucket.

   Third wipe should be final wipe. By now, no grout should be on tile, just a few sand grains. If you have grout in surface irregularities of tiles, you need to wipe this off before it dries.

   Wait 8-24 hours before sweeping floor clean. Wait 36 hour after all grouting before applying sealer.

   Slate is not very pourous, but it will take some sealer. A caveat: it is quite possible for you to use too much water during the grouting process, wipe up water when you see it, it can cause the grout to dry to different shades. For slate, I make my own grout with 2 parts common cement to 1 part silica sand (20 mesh). If you want a colored grout you can add stucco color or just buy the colored grout.

   Do not think you can use acid to correct an imperfect grout job. And, good job in pointing this out, RichardB, do not wax your slate floor.

   Loquaciously, Rich

1. 
   Guest_ | Apr 02, 1999 01:56am | #7

   *To be gently contrary (a hobby of mine), our slate was quite consistent in size and thickness, and the gauged backs quite smooth, I think because it was of a decent grade. Construction adhesive from a 3/16" V-notch trowel worked OK too, directly to the 3/4" plywood subfloor. We've been stomping on this stuff for months now with no ill effects.I was very skeptical about the thickness of the subfloor, the lack of cement board, and use of glue, but I did it anyway on the strong advice of my stone supplier. Slate is not quite like tile it seems. No problems, and I think a faster job.No kidding about cleaning the grout! Lots of work there.

1. 
   Guest_ | Apr 02, 1999 11:23pm | #8

   *The slate I've used was gauged too, ground smooth on the back. And it is fairly consistent in size, but even +/- 1/16" will throw things off if you use spacers over a relatively large area.Direct from the quarry in VT, gauged A Grade slate runs from just under 2$ to 3$/sqft. More for the fancy mottled varieties. Green is the least expensive, and mixed color packs are even cheaper. We paid 2.35 sq/ft for 400 sq/ft of purple, delivered.

1. 
   Guest_ | Apr 03, 1999 06:09am | #10

   *Good point -- I thought you were talking about larger deviations in size. I used chalk lines as sanity checks. Again, it's not exactly tile.

6. 
   Joe_Ruedinger | Apr 03, 1999 06:09am | #9

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   I am about to install (green) slate tile in our foyer and powder room. In the foyer we removed the linoleum down to the 3/4 plywood subfloor (we removed a great deal of the adhesive along with the linoleum but there is still a fare amount left, do we have to get all of it up? If so what is the best way? We used a ¾” chisel to get this far). We plan on thinsetting and screwing 1/2" concrete board down, then installing the 12x12 tiles (1/4 x 1/4 notched towel). My questions: 1.) what type of grout and how to get it off the tiles after? I have heard it is necessary to use acid to wash it off, is this correct? and what is the process? 2.) I will have a transition between the tile and a soon to be installed wood floor. The build up of the tile will be be close to 1" while the wood will be 3/4". How what is the best way to transition- add a 1/4" piece of laun under the area of the wood floor, bevel the edge of the slate tile to the wood floor, or? Also, How do I treat the edge at the top of the stairs, since that thickness will now be about 1 3/4" thick? 3.) I have heard that impregnating sealer are the way to go, any specific brands? Thanks in advance for your help.