No More Ply, Or Insulation Boards?

[Flintstone]

how do chaps, been reading on here from time to time and thought I would sign up, so,ex good info on here.
I have a job coming up, 90sqm or large format porcelain.
The floor is concrete and is having underfloor heating mat throughout. The question is what to put down first, just concerned about the foam boards, apparently, the tech support for the foam boards said a 6mm screed of slc would be required over the wires to give it the strength. Sounds dodg to me. no more ply stuck down with flexi rapid gonna be a good option ?

 

[Andy Allen]

I would go with insulation boards, the slc over the heating mat is to protect it and help disperse the heat. ..

 

[Flintstone]

I'm just not convinced by the strength of the boards

 

[peteablard]

I'm just not convinced by the strength of the boards

Why not?

 

[Flintstone]

I've tiled over them previously on a concrete floor and it didn't feel rock solid under foot.

 

[Andy Allen]

There more than strong enough......I know they don't look like much but it's all about spreading the weight, ...

 

[peteablard]

Not sure why, as Andy said above I'd stick boards, SLC over the cables then tile.

 

[Flintstone]

Just stuck down with rapid set? Is there anything wrong with sticking no more ply down with rapid ?

 

[Andy Allen]

Think you will find most tilers on here tile over insulation boards with no issues at all...........
I thought no more ply had to be stuck with there own glue.

 

[Flintstone]

It looks like they have ordered the no more ply so will be going down that route!

 

[hmtiling]

It looks like they have ordered the no more ply so will be going down that route!

i wouldn't use nmp on a solid floor. The 6mm ones have a tendency to curl up when fixed with addy and not screwed. The insulation boards are definitely the way to go. Fixed down with rapid and slc on top.

 

[On one]

The think the only reason for concern for using insulation boards on such a large area would be if you used really thin boards and there was a risk of the boards being compressed too much by people trampling over them prior to laying the SLC.
If you can control/prevent who is walking over them there shouldn't be a problem.

 

[Tile Shop]

On a solid base, Marmox Multiboard can handle 40 tonnes per m2. Does King Kong visit often? It has been designed with this very purpose in mind, so I doubt very much its going to fail. The SLC will also help evenly spread the weight and heat distribution.

Also, using nomoreply will allow heat to go down into the subfloor aswell as up.... It will therefore run less efficiently and your running costs will be higher.

 

[Flintstone]

Apparently the tech support for whichever thermal board company said the thin 6mm board isn't strong enough for the job!

 

[Lee@emctiles]

confused, are we talking foam boards (ie uncoated) ?

I would go with 10mm DeltaBoards, a thermal insullation board (marmox/Wedi type) over No More Ply.