Advice on limestone floor installation

[Pete.c]

No, I would put movement joints in, but where, apart from doorways, and at what distance apart?

It is really difficult to find a certain solution, i`ve hunted round on the lafarge site and found this Broken Link Removed.

Also Nicobond Gypfix is 100% compatible, seems like a possible answer.

These both seem to suggest that decoupling is not necessary.

 

[Ajax123]

No, I would put movement joints in, but where, apart from doorways, and at what distance apart?

It is really difficult to find a certain solution, i`ve hunted round on the lafarge site and found this Broken Link Removed.

Also Nicobond Gypfix is 100% compatible, seems like a possible answer.

These both seem to suggest that decoupling is not necessary.

i wrote that....whilst I was still at Gyvlon....

i agree that if you are using non natural tiles like porcs an uncoupling membrane is not required in general but limestone being relatively soft is prone to fracturing due to thermal cycling. There is an argument to say that gypsum screed and gypsum adhesive with limestone on top would mean that all three elements move in a similar manner and to a similar extent but my advice has to reflect the British Standards where they exist as these reflect inspdustry best practice. Simple fact is that if you step outside of British standard and things go wrong you will have no viable defence. British Standard says natural stone then uncouple.

If you use gypfix to stick down the mat make sure you don't prime the screed as it will rely on moisture loss to set fully. Unfortunately you will also find it difficult to get a recommendation to use gypfix from the likes of schluter as they have done no testing. A call directly to nicotine might be helpful.

 

[SJPurdy]

Would expansion in the doorways be enough? I will still have a run of 9mtrs by 7.5mtrs in the kitchen diner, its an L shaped room.


The maximum distance between movement joints on a heated floor should be 8m and the maximum area between movement joiunts should be 40m2; thats a general recommendation of BS. With an L shaped room it may be advisable to break it into 2 rectangles as there will be a stress point at the corner (In my opinion this should have been put into the screed) - I've seen floors where Ditra was used but no movement joint so the tiles were cracking from the corner ouitwards.

If you're going to use Ditra I advise giving their help line a call - they are very friendly and helpfull - have the dimensions of the "L" ready for them to advise on.