Suspended timber floor. Foam Vs HB/NMP/A-Panel - Tile Advice

[Waluigi]

Standard suspended timber floor, regarding overboarding- do people consider the foam boards (wedi/Marmox/Jack0/Ducka etc) as good as the boards like Hardiebacker/NMP/Aquapanel etc.

I’m asking this in relation to UFH and suspended timber ground floors where the insulating properties of the foam boards exceed those of the other boards.

I’m assuming the 12mm foam boards aren’t a whole world different to the 6mm Hardiebacker boards.

 

[Dumbo]

I 've asked harry hill about this and he says the only way to find out is fight !
But seriously as far as insulation is concerned foam boards will beat cement boards every time

 

[Dumbo]

Just checking . If it's wet underfloor it would have to be cement boards if its electric undertile heating then foam

 

[Waluigi]

My mistake, yes absolutely it’s Leccy UFH.

One thing I was wondering, I tend to use 12mm HB when laying natural stone. I’m wondering if 12mm foam board is good enough. I’m not entirely sure it is.

 

[Dumbo]

Should be ok but I have seen some people recomend using ditra on top of elec ufh as well as using foamboard underneath .

 

[WetSaw]

Obviously foam board wouldn't add any structural rigidity to a timber floor in the same way a cement board does.

 

[Flintstone]

there’s no structural gains from a cement board, pdc, despite the feeling of solidness after it’s fitted.

 

[WetSaw]

That surprises me Andy. I'd still rather use cement board on timber than a foam board, not that I've ever seen a timber floor over here!

 

[Qwerty]

Foam boards allow very slight decoupling whereas cement boards dont

 

[Waluigi]

Why are we still using Hardiebacker and the like instead of Foam boards on floors?!

 

[Dumbo]

Why are we still using Hardiebacker and the like instead of Foam boards on floors?!

Most foam manufacturer's recomend minimum 10 mm on suspended floors where as cement boards are ok at 6mm . So height build up I guess