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.......

[pjtiler]

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]

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]

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

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!

[GazTech]

Thanks for the thanks fox...this is what we enjoy doing......Gaz

[Dave]

We aim to please............that's why tilersforums is the UK's no 1 tilers forum.... .

Good luck with the job and let us know how it goes and maybe a few pics of the finished job would be nice........

[TilingLogistics]

As a matter of interest I was wondering if you had actually discussed this with your tiler? 83M2 of Large format limestone laid Brickbond is not an easy task by any stretch of the imagination over such a large area. I am of course assuming there will need to be expansion joints incorporated and laying out to run into other rooms.

I am in the process of correcting a similar job right at this moment which is slightly larger 135M of Large format limestone 600 x 400 laid BB running through 4 rooms in a barn conversion. The job has been laid without any expansion joints and over UFH and the tiles have lippage everywhere. I have to grind the whole lot flat install expansion joints and hone and polish to get it right and all because the tiler had never dealt with such a large floor before.

Kev

[Caleyfox]

The tiler has seen the area to be done and has had a sample of the tile. What form should expansion joints take if there is a BB pattern?
Thanks Caleyfox

[GazTech]

Expansion joins can only run one way with BB pattern, you cant put expansion in zig- zag way...lol

[TilingLogistics]

The tiler has seen the area to be done and has had a sample of the tile. What form should expansion joints take if there is a BB pattern?
Thanks Caleyfox

Expansion joints should be every 10 linear metres on a run. As Garry from BAL says they are fixed across the grout line. I would also adopt a belt and braces approach and install a silicone bead all the way around the exterior walls as well. Preformed expansion strips are available to purchase from Schluter and Dural to name but a few. You can also get the insert to match the grout.

Kev

[Branty]

On this floor the architect specified plenty of movement joints, the job was 350 sqm's in total. Where the expansion joint comes down the tiles, you need to trim enough of each tile the butts up to the joint for it to look right.

[Branty]

You can see it better here.
On the centre expasion joint, which was 10mm, with a 3mm grout joint either side. We had to trim off 8mm from each tile.

[TilingLogistics]

You can see it better here.
On the centre expasion joint, which was 10mm, with a 3mm grout joint either side. We had to trim off 8mm from each tile.

Danny,

Can I ask why the expansion joint was run vertically as opposed to horizontally? After all the room doesn't look that wide to me!

Kev

[tiler burden]

and what a dogs r's that job looks!!! architects should stick to what they know, designing building's and leave engineers and surveyors to do the science.

answer to kevs questions...

if that building is a new build, then the settlement will take place on the outer walls, which could?? form stress on that section of the floor. as you can see, if the footings where to settle slightly then the stress would follow the floor expansion joint which is parellel to the outer wall. this puts the decision to use a brick bond pattern under the microscope!! obviously a pattern that incorporated the expansion joint would have been a more asthetic.

[Caleyfox]

Branty
On the photo (with the spirit level coming out of his head) - Is that a Diramat that is being tiled onto and is it on top of plyboard?

Regards

Caleyfox

[Branty]

No I took the picture. The matting is Dural Matting.
The building is an old building, The screed was about 20 years old [last time it was refurbed].
The screed had cracks running down and across the floor, at regular intervals. The archiect wanted expansion joints running above where cracks had formed in the screed.

The row of dark ones dont look that dark in the flesh.