Undertile heating over ply, with granite tiles , opinions please.

[peegee tips]

Hi all,
Looking for some helpful advice if poss please..
Quoting on a job in a bathroom which is a ply overlay floor....customer wants, UFH, with granite tiles.
Now i've spoken with a few heating suppliers & adhesive suppliers, but i have conflicting opinions.
I'm so far aware that there is no self leveller available that can be laid directly over heating which is laid on ply, they don't entertain it, & doing this is likely to end in tears with expansion & contraction of the ply.
Would the right thing in this situation be to overlay the ply with Insulation backer boards ( flexi ad ) , then lay heating, self level then tile ( flex ad )?
Many thanks.

 

[wivers]

Uheat Aaron will put you right mate.

 

[pete f]

done a few like this i stuck ins board down with flexi never had any problems gd luck pg

 

[pjrich]

Hi all,
Looking for some helpful advice if poss please..
Quoting on a job in a bathroom which is a ply overlay floor....customer wants, UFH, with granite tiles.
Now i've spoken with a few heating suppliers & adhesive suppliers, but i have conflicting opinions.
I'm so far aware that there is no self leveller available that can be laid directly over heating which is laid on ply, they don't entertain it, & doing this is likely to end in tears with expansion & contraction of the ply.
Would the right thing in this situation be to overlay the ply with Insulation backer boards ( flexi ad ) , then lay heating, self level then tile ( flex ad )?
Many thanks.

Everything you suggest looks fine to me, only thing I would add is that we normally screw down the backerboards to the ply. I would recommend using Thermopanel, Marmox or PCS boards for the insulation.

 

[peegee tips]

Everything you suggest looks fine to me, only thing I would add is that we normally screw down the backerboards to the ply. I would recommend using Thermopanel, Marmox or PCS boards for the insulation.

Thanks Pete,

Would screwing the boards down stop the flexible adhesive doing its job?
I mean would the boards then move as much as the ply through expansion?

Just a thought.

 

[pjrich]

I've attached a pdf from PCS which indicates the recommended way for fixing backerboards on timber floors.

The boards won't have as much lateral movement as the ply if installed correctly so you shouldn't have any problems with cracking, etc.

 

[DHTiling]

Uheat Aaron will put you right mate.

He dose not work for Uheat anymore wivs....keep up mate...:smilewinkgrin:..
Aaron left for another job.....

 

[redlee]

If the floor is already ply'ed you could try tilemasters levelflex, suitable for ply and u/floor heating give them a bell to confirm.

 

[STEVO]

Might be a bit late with a replyfor ya, but i think granfix do a slc thats flexi and can go over heat cable/mat.

 

[peegee tips]

done a few like this i stuck ins board down with flexi never had any problems gd luck pg

So without any heating would there still be a need for anything between the granite & ply?

 

[redlee]

So without any heating would there still be a need for anything between the granite & ply?

Ply, prime, adhesive (spf) and tile.

 

[lol knowles]

keep away from ply put 6mm hardibacker on the ply flexible level compound on top then tile it with rapid flex cover your back better to be safe

 

[doug boardley]

keep away from ply put 6mm hardibacker on the ply flexible level compound on top then tile it with rapid flex cover your back better to be safe

Lol, it's nearly 18 months old is this thread:lol::lol:

 

[Mike]

i think this thread's so old now the floor's ready for a retile :lol: