Client has asked me to convert a heated garage space into bedrooms for his extencded family. (boy lawyers are prolific.) The garage is heated via RFH. The bedrooms floors, (2) will be finished with a floating laminate flooring. The entry hallway/foyer will be done with 12X12 ceramic tiles. My question is 2 part.
1 As the polished concrete floor has a sealer on it, can I use modified thinset to set the tiles, or will I have issues bonding the tiles to the floor. Do I need to cut through the sealer on the concrete?
2 The concrete floor has been kerfed for stress relief. I need to bridge the kerfs with my tile. What are some products or techniques to accomlish this?
Thanks for your considered opinions.
Erwin
Thornbury, ON, (Where the ski slopes open for the weekend)
“the hurryer I go the, behinder I get.”
Replies
If you have time to test a patch of tile installation, even one tile, you would see if the tile will stick to the floor. Sometimes a scratch coat of modified thinset cut with an acrylic bonding agent will help the bond. I have used KeriLastic products with success. To remove any doubt, though, grinding it back to the raw 'crete is probably best. Dust collection becomes the big problem on an interior job. Do the grinding first before anything else goes in there. Good 'at source' vacuum collection is best.
Bridging the cracks, which are acting as control joints, is a riskier proposition. If there is any movement at all, the tiles will crack. How old is the floor? Has any settling/cracking occured yet? Designing around these cracks, ie putting a grout line along the control joint and caulking it, or fitting a brass strip into the joint and tiling up to that.
To bridge it would require a fibre-mesh strip like the stucco guys use, laid in a bed of thinset. Even this won't with stand cracking.
Sounds like an ideal application for Ditra:
http://www.schluter.com/english/products/2002/sectionf/ditra/601-ditra.html
Saw some commercial tile setters use a roll-on blue colored product onto concrete and embed what looked like fiberglass mesh into the blue stuff.
The tilesetter said it prevented the tiles from cracking and he said it works. The blue stuff was troweled into the control joints on the ground floor and rolled onto the rest of the floor.
The tile used was 18" square porcealin.
I don't remember the name of the blue compound, but it should be available at any professional tile shop. It was premixed in one gallon cans.
The concrete on the job where the tile was set was not sealed.
I think several companies have "uncoupling membranes" like that, which bridge cracks, and let the slab shift a little bit without cracking the tile. I'm sure laticrete and custom make them- a roll on or trowel on product, with a sheet material over it.
I think it's the way to go for the op, too.zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
Just a thought. Depending on the thickness of the laminate floor vs. the tile, and whether you need to build up the tile floor to achieve a matching thickness w/ the laminate, going with cbu over the slab may alleviate having to deal with the sealer. I'd still use Ditra under the tile no matter what.
Ditra, and be done with it.
Don't sweat it, just get a chisel and chip the floor every 8 to ten inches or so and use modified thinset, then buy youself some schuyler ditra and run a strip over that joint, a tile with on both sides.