Hello all,

I was over at a neighbour's house on the weekend, and I'm really hoping I'm not right about their floor.

They're having limestone tile laid, I'd guess about 16 x 16, and there is practically no space being left for grout. I'd say about 1/16 to 1/8". Is that enough?

They're having the entrance, foyer, kitchen, bathroom and laundry room done, and it's about half way along.

Thanks in advance,
John

Yes - Grout is a joint filler no matter what the size. On all my stone installs ive always butted the tiles.

More important, is how was the subfloor / underlayment preped?

Odds are 10 to 1 its a wire/scratch coat job. Lets hope not!

technically that is not the 'recommended' joint size of a tile, as that is not much room for expansion which is realy all a joint is for. However limestone is a very soft stone and will probably not tent or pop up as it is soft. That being said limestone is not ideal for floors because it IS soft and will wear where you walk as it is actually ancient sea floor compressed, its like one-up softer than shale, which is mostly ancient mud or clay. One reason you don't see limestone floors at churches where the whole exterior is limestone. Limestone is fireproof. Marble is also not recommended for floors as it is a form of limestone, pretty soft. Slate is almost like shalestone but is more durable, enough for floors anyway. A good stone with the color they like would come from a stone called quartzite. Quartz being the base stone. Very hard and dense, really pretty and durable. A limestone colored slate would also be a good choice in a gauged thickness.

Thanks for the answers. Seems there's room for artistic interpretation of joint sizes, so I won't mention anything to them.

As for the sub floor, they had ceramic on these floors previously. This was removed, and the contractor deemed the sub floor to be sound, and they are installing over it. There had been absolutely no problems with the ceramic, but it was certainly "dated".

Lots of useful information in these forums. I may be back with questions of my own!

Regards
John

That isn't the reason for grout lines Bradely, sorry. Grout isn't meant to absorb stress or deflection anymore than the tile is able to. That's why control joints and expansion gaps are required. Also, marble and other stone products you mentioned have been used to construct floor finishes for a few thousand years. In fact I'm doing a home right now with several types of marble all through and would be very upset if my customer was to be misled by your last post. Sorry, not meaning to upset the cart.

Rob and RC are correct in stating that any size grout line may be used. Just need to the appropriate grout for the desired grout line size.

Its my understanding that when a ceramic tile is made they press moist clay what 16-18 inches and when fired it shrinks to 12. So that same tile expands and contracts with heat and moisture. I dont think a mountain expands at the same rate. Most tile guys i know do not build the subfloor strong enough and have butted joints crack when using unsanded grout and their solution is wider joints and sanded grout (which is stronger).

I agree with Mike. Any tenting issues should be addressed with a solid substrate accompanied with full permimeter expantion joints and control joints. As far as joint size is concerned, it is my understanding that there should be some space left between tiles (even as small as 1/32") to allow the grout to achieve a mechanical bond.