Replies

1. 
   Guest_ | Nov 30, 1999 03:35am | #1

   *
   The last stone floor over a slab on grade I did involved the following:

   Install slipsheet over slab. This was scribing felt intended for vinyl floor installations.

   Determine layout of stone and snap chalkline grid.

   Backbutter each tile with acrylic modified thinset and install in wet mud.

   Preparation of slab for slipsheet includes sweeping all debris off subfloor and may include patching small holes and washing of subfloor. Felt is layed with Type II mastic as adhesive. I use a grid of chalklines because this allows me to begin installation of tiles anywhere on the floor. You may prefer using only one or two lines, which would be fine. I backbutter with thinset because this gives better bond to the wet mud. You may use a neat coat of pure cement and water over the wet mud bed. Besides, the use of thinset in place of the neat coat is faster and less messy.

   I also use a 2' level to check each tile and also to keep me at the finished floor elevation. A taut string set at the elevation of the finished floor will also help to keep you in plane. You don't want to create high or low spots in the floor. Also, step back every now and then and cast a critical eye on your work to make sure you are staying at the FF elevation.

   Whatever you do, stay on those lines when setting! Make sure to avoid getting mud between the tiles which would inhibit a tight joint. And, you will get tiles which are +/- 1/8", so you should be forewarned in regards to how you plan on using these. I simply set them somewhere in the field and not on the lines. Also beware of the vugs(holes) in the tiles. A too large hole will create a thin spot(read weak) in the tile. A thin spot on the tile should be filled or cut off. You are not creating something that will look machine made, but a work of art. The "imperfections" add to the charm.

1. 
   Guest_ | Nov 30, 1999 11:40am | #2

   *Thanks Rich your help is much appreciated.John

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   Guest_ | Nov 30, 1999 01:07pm | #3

   *Yeah, like Rich said "averaging the field". I would suggest you look around for a pro (like Rich!!) who knows what a buttering board is (if the stone is off gauge even the slightest), use a good medium bed thinset and have on hand a Makita palm sander to vibrate the tile to plane.3/4" mortar bed?? Rules out a thinset or medium bed thinset method doesn't it Rich?Why, if I might ask, do you mention 3/4" setting bed? Transitions to other finish flooring?Jeff

1. 
   Guest_ | Dec 01, 1999 05:57am | #4

   *Thanks Jeff. You reminded me of using a "shooting board" and the sander. The only time I appreciated the buttering board was on a slate job where the slate ran from 1/4" to 1 3/8" thickness. Other than that, I can go faster without it. Also, I thought the palm sander was a secret trick in my bag o' tricks. Silly me.I'd say John wants to match elevation of existing floors. Sometimes, folks will bury their metal threshold under the tile. Well, they'll go flush right to the top of the 1 3/4" ht. treshold.

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   Guest_ | Dec 01, 1999 12:22pm | #5

   *thanks - both of youi am trying to match the 1-1/4" height of a 1/2" maple floor o/ 3/4" ply o/ a concrete slab. don't ask me why i'm putting wood over concrete!!! can i use a 3/4" morter bed (1/3) instead of thinset? do i need to use white cement because of the light color of porto - beige limestone.don't hold anything back. tell me more from your secret bag o tricks.but, seriously, thanks a lot - i do want to do a really good job on thisjohn

2. 
   Guest_ | Dec 02, 1999 06:14am | #6

   *Do not plan on using thinset mortar--modified, white, grey, or otherwise--over 1/2" in thickness. John, you seem to have reservations about a 3/4" T mud bed. Sure, go ahead with the 3/4" mud mortar bed, just adhere the tiles to the wet med in using either method I mentioned previously. As for white cement, I don't think it is necessary. I have set lots of white, permeable stone with grey thinset/mud without bleed through, the one exception being white marble.You will want to avoid using a felt tip marker though. This will bleed, as will any water soluble ink. I use a 16d nail, a scratch awl, or a #2 pencil for marking cuts. Just make sure to rub off the pencil before installing.