Can limestone tiles be laid on a floating floor without cracking?

[Caleyfox]

Any help really appreciated
New build concrete floor has masses of central heating / water pipes running across it.
Decision to lay limestone tiles (large 24" x 12") over a 83 sqm area not communicated to plumber.
Now have a concrete floor with 2" timber battens at 300 mm centres and 18mm plyboard on top.
(When heating / boiler is on, pipes will generate a lot of heat under the plyboard).

Can anyone give any guarantee as to how limestone tiles can be laid in this situation?
What I don't want is for cracking of tiles / grout several months down the line

Thanks

[Dad]

The 300 centres should be ok, assuming the joists are in contact with the floor all the way, but install noggings around the perimeter of the room to prevent sagging at the edges. Either way use a proprietary flexible adhesive and grout.

[Dave]

If the floor is well secured and deflection is at a minimum and the perimeter is secured as Dad mentioned then overlay with Ditra mat, this will help stop any lateral movement from cracking the limestone.......

i,d think about a few expansion joints theres going to be a fair bit of movement

[Caleyfox]

Thank you Dad, Dave and pjtiler for your responses.

[wetdec]

Can we establish what limestone we are talking about is it travertine wrongly labelled, white limestone, Jerusalem or one of the Jura's. And the thickness of couse.

If we know this then we can better tell you what it is you need to do



tiler

..

[enduro]

I laid a limestone floor on top of 18mm ply, that had underfloor heating (water) and these people have the heating flat out all winter, i laid it two years ago and no problems

[Caleyfox]

I have been advised that the limestone is 12mm thick and is gold eider limestone - similar to Jerusalem limestone apparently.

[wetdec]

Originally Posted by Caleyfox

I have been advised that the limestone is 12mm thick and is gold eider limestone - similar to Jerusalem limestone apparently.

So then it is quite a hard stone with fischers in it and at only 12mm would benefit from either :

Over boarding existing new floor with a 6mm ply crossing existing joints

OR

the use of ditra or durabase CI matting to relieve deflection.


If these tiles are to be laid as a straight lay I personally would say 1 of the above is essential.

tiler

..

[garythetiler]

there is some good advice on this post but you originally asked if there is a guaranteed method for this installation and the truth is there isnt all you have is whats called, best practice, which is covered by the advice you have above ,you should be alright if the floor is stable 18mm ply ditra matting good luck

[GazTech]

[quote=garythetiler;79494]there is some good advice on this post but you originally asked if there is a guaranteed method for this installation and the truth is there isnt all you have is whats called, best practice, which is covered by the advice you have above ,you should be alright if the floor is stable 18mm ply ditra matting good luck[/quote]Good posting Gary, good advice......Gaz

[Caleyfox]

Thanks Gary.
You are right with there being no guaranyees only best practice in the circumstances. It is a case of shutting the gate after the horse has bolted but I have received very useful guidance and methods to pass on to my tiler from this forum.
As a newcomer who only joined Friday, I am amazed at so many people going out of their way to help someone. Good on yer Tilers!