Tiling my kitchen floor - slate tiles

[Qwerty]

I've amended and added your images into the thread for ease of access & viewing

 

[SJPurdy]

I think that a 4mm joint width is a bit optimistic. All of the slate I have fixed has required double this to accommodate the variation in sizing and the non flatness of the slate.
Likewise the slate that I have fixed (even the calibrated) has varied in thickness/ flatness so much that I would recommend a tile notch size greater than 10mm.
For the same reason I am not sure the levelling clip systems will help that much with slate but then I have never tried it.
Slate takes longer to fix than general ceramic tiles because of the variation in thickness which needs to be accommodated by varying the thickness of the adhesive bed (that will depend on the quality of the slate, flatness and pre-sorting/calibration); and all cuts need to be none using a wet saw (or equivalent). You may be optimistic about getting it all fixed in 2 days.
An alternative to brick bond would be random bond and this can make things easier as you can plan so that full tile joints hit things like the edge of the island unit.

 

[Futuregrout]

I thought I would let you all know how it went.

Prep and laying decoupling membrane:

I started two days late due to work commitments, so I only emptied the kitchen on the Friday night. It took me all of Saturday to get cleared up, sort out the layout and get the decoupling membrane down. It was roasting hot all day - rapid set was a bad choice, and totally unnecessary in hindsight. I used the Kerakoll mat recommended on this thread. I found it harder to put down than ditra mat and I did have a few issues smoothing it out properly. I will give myself a 5/10 (10/10 being the result achieved by a good professional tiler) because while I did get it done per the instructions, it took me forever as I had to mix up the rapid set in such small quantities. Even with my dad helping by doing the mixing, it took ages.

Working out a layout:

It took 2 hours on Sunday to work out the layout. I am very pleased with the layout, it was pretty efficient and I think it just looks "right". 2 hours well spent. I will give myself 9/10 for the layout - I think it works really well, although I am sure others would find problems with it.

Laying tiles:

I used a 12mm trowel following suggestions on here, and back buttering the back of the tiles with maybe 2mm of adhesive. I was using semi rapid set adhesive, half a bag at a time, with 5mm spacers (admittedly ignoring the advice here, but I thought the tiles were pretty uniform and that I could manage a smaller space). I also used Rubi levelling clips. It took me a long day and a half to lay the tiles.

I will give myself 6/10 here. On the whole I think I did a decent job and, as a DIYer, getting all the tiles down in a day and a half (Sun PM and Monday) felt like a result even with my dad helping by mixing up the adhesive and cutting the tiles. The vast majority of tiles feel and look flat, level and flush... but there are 3 or 4 where I can feel a lip when stepping on them and I just know it will drive me nuts over time. I am not sure what the rubi clips achieved to be honest - I couldn't see any obvious difference they made, and they broke as soon as I squeezed a bit to hard. The size of the tile was less of an issue than I had thought, and as someone on the the thread above said, anything smaller would have looked wrong in the room, but the little plastic rubi clips seemed incapable of doing anything to level up the heavy tiles. I also made more mess than I expected to - in particular right at the end (the nearest tiles in the picture - they have since been cleaned up).

Grouting will have to wait until the weekend because the supplier didn't actually ship the grout, and because I ran out of time and energy anyway.

Overall: I am pleased to have got it done but it was really hard work, a pro would have managed to get a better finish, and my knees are killing me! I would do it again if I had to, but my hope is that next time I will be in a position to pay a good tiler to it instead. Thanks everyone for the advice!

 

[Flintstone]

Looks good you have done well. Remember to seal them well before grouting and again after and be careful moving the fridge as slate scratches extremely easily

 

[Tile Shop]

Looks good you have done well. Remember to seal them well before grouting and again after and be careful moving the fridge as slate scratches extremely easily

To go one step further on Locals post, agree. Good job. Have you picked out your sealer yet?

As he says it scratches just by looking at it. Even after it is sealed, with most clear sealers, the scratches are still visible even after applying a further lick to try and blend it in.

Recently had some dealings with a honed slate. A fart from 3 blocks away can scratch it. Oil based sealers (like LTP Stone Oil or Lithofin Slate Oil) are by far the best [IMO]for the initial seal and to perfectly touch up scratches if they ever occur after installation, which i'm sure they will.

 

[Flintstone]

My recent slate job I used stainstop mn which was good, slate isn't very porous, I think I used around 1.5lt for 40sq m

 

[Futuregrout]

Thanks both. You are right about the scratches - I couldn't believe just how easy it was to scratch them. We have metal based stools for the island but I'm going to cover the bases with felt before putting them back. I actually wanted the honed slate but the supplier almost refused to sell it to me when I told them it was for a kitchen floor because they scratch so easily.

As regards sealer:I have lots of ltp matt stone left over from the bathroom so was going to use that but open to suggestions for better options