My husband installed our slate mosaic. I don't have answers to all your questions, but I can say that the type grout you'll need depends on the spacing between tiles. I'm pretty sure you'll need unsanded with 1/8" spacing. Our grout came off easily, even though we did not seal the tiles until the grout was finished. I suggest trying out the sealer on a few tiles to make sure it gives you the look you want. Some sealers don't change the look of the tiles; some change it significantly.

I'm pretty sure we didn't rough up the paint. No screws were needed to hold the 12"x12" sections in place. We did not even try to get all of the tiles even. With what we used, it would have taken forever, plus we like the variation, and it made it far easier to install the tile since we weren't having to aim for perfection.

While I didn't do the actual install (I helped with the grout), I can say it wasn't all that difficult. My husband had never done any tile work, and ours turned out fine. Good luck!

Thanks, Lynnette! What was your grout space? How did you grout it? just trowel in?

I tried some sealer on my sample. I liked the enhanced look, but who knows for sure until it is on the wall. I thought I really needed sanded because of the slate tiles. they are thick for tiles I think. How thick were you mosiac pieces? Did you use thinset to place the 12"x12" sheets?

Our tiles (mostly 1"x1") have got about 1/8" between them. We put the grout on with a trowel. The tile was put on with mastic. I'm certainly no expert, though, so hopefully someone like Bill V. will chime in here to answer your questions.

In case no one has told you, be sure to use caulk where the tile meets the countertop, rather than grout. You should be able to buy caulk in the same color as your grout.

Use Thinset not mastic--What trowel should he use? Only backbutter if needed? Can use screws to help hold sheets in place until set. They are fairly heavy with that slate.Do we need to rough up the paint surface in anyway?

Use a 1/4x1/4 square notched trowel, and you're right-- you want thinset instead of mastic for the stone. Now, as for helping the tile stay up-- you want a certain KIND of thinset. What you want is one of the new lightweight thinsets. They're made to have alot of grab to them when mixed properly, and the tile WILL NOT SLIDE-- just like mastic. The three most common are Dustom Building Products' Megalite, Laticrete's 255, and Mapei's Ultralite. All three are good thinsets and will work. They get mixed alot stiffer than normal thinsets and will literally grab onto the tile when you set it.

We were planning on buying a inexpensive 7" wet saw to make cuts. Will that make cuts okay for this job? Renting is not really an option for us on this DIY whenever have time job.

I got good news and bad news for you-- the good news is the smaller saw will do fine. The bad news is you're going to want to take those pieces off the mesh and cut them one at a time. The reason is that the mounting glue that holds the tile on the sheet is water emulsive, and once the sheet gets wet, you're going to have a mess on your hands trying to put it up on the wall.

After tile up and set/dry, apply sealer/enhancer to slate. I am unclear about this. This would really help with grout release. Grout release is a concern. Tiles are small and rough. Grout lines are very small also(1/8). DH is most concerned about the grouting. If I do before grout, then I will have to do again after grout to seal grout.

You can seal it before, after, or both. Being that you're DIYing this, I would strongly suggest sealing prior to grouting for the reasons you brought up. However, you can also reseal it all afterward to bring out the color in the grout, as well. One thing about sealing afterward-- make sure the grout has time to dry for atleast 48 hours, and preferrably 72, if you can wait.

Grout with sanded grout?

Absolutely.

DH wonders if a brick is not positioned correctly on the mesh if he should pull it off and position right when thinsetting to make grout lines more even.?

Believe me when I tell you-- especially with slate, if he starts with one, by the time he's done, he will have set that entire backsplash one piece at a time. yes, if one is really cockeyed, then go ahead and straighten it out. But if you look at the sheets, you'll see the pieces are all different sizes, as are the grout joints, many aren't square, they'[re varying thicknesses, etc.-- basically a nightmare for someone with OCD!! As a contractor I did alot of work for years ago used to say, that's the beauty of rustic tile!! :-)

I am planning on using Miracle Seal & enhance, although tile manufa recommend TileLab but I cant find it. Any thoughts?

They'll have Tile Lab at Home Depot. Not one of my favorite brands, but there are some who'll swear by it. Personally I prefer the Miracle product line. IMO, a much better product line.

Is Custom Polyblend grout(from HD) okay or should I try to get some other brand?

That should be fine.

Thank goodness you're here, Bill. Our installation went very smoothly, and tile has been fine for almost two years, but sounds like some of the advice we got was not the best. We were sold mastic and unsanded grout, and by a supposedly good tile store.

I'm cutting and pasting Bill's post onto my desktop to refer to in about a month!!!!! THANKS!!!!!!!!

A blessing on the house of Mr. Vincent-- unfailingly polite, accurate and clear!

Long may he prosper.

Thank You Bill!!
You are so nice to answer every little question and worry. I should be able to find one of the thinset brands you listed. Given the texture of this slate, I think presealing would be a good idea. After waiting and looking for 5 months I really dont mind the extra step.

I will keep you posted on the progress. May be a little while longer before we start. It does sound doable.

Is there a better way to cut the slate little mini bricks?

May

When you go to seal it, you don't want to really soak it down, but at the same time, don't get overly paranoid about getting sealer on the edges of the tile. The grout WILL still stick. Also, you should be able to find the Custom Megalite at HD, and either the Laticrete 255 or Mapei Ultralite at Lowes (some carry one, and smoe carry the other).

As for cutting the slate, you might be able to cut them dry with a 4 1/2" grinder and continuous rim dry diamond blade. It depends on how bad the slate shales (has layers come off). It would actually work better than a wet saw for you, for a couple of reasons. First, it'd be alot cheaper (about 65.00 for the grinder and another 20.00 for the blade), and secondly, you could make your cuts with the tiles still on the sheet.

Now, as for helping the tile stay up-- you want a certain KIND of thinset. What you want is one of the new lightweight thinsets. They're made to have alot of grab to them when mixed properly, and the tile WILL NOT SLIDE-- just like mastic. The three most common are Dustom Building Products' Megalite, Laticrete's 255, and Mapei's Ultralite. All three are good thinsets and will work. They get mixed alot stiffer than normal thinsets and will literally grab onto the tile when you set it.

Bill - will Custom Building Products Omnigrip work just as well as the 3 you mention? I searched both Lowes and HD and neither had any of the above. I did find the Omnigrip at HD and it talks about being lighter weight / resisting sagging, etc.

Thanks

Here is a link that might be useful: omnigrip

OOps - I should add we too are doing a slate minibrick backsplash installed on drywall