Hardi backer boards

[Bri]

Tried to find some data but can't find much. Can they be used as insulation boards? I know that marmox boards can be used specifically for this purpose but wasn't sure about the hardi's.

Thanks Bri

[Dave]

Hi Brian..

Sorry but nope they are not for insulation purposes..

[TF Ed]

hi bri
there not that good for insulating....you will need wedi, marmox, schluter board etc for good thermal qualities..

ed

[Bri]

Thought so, thanks folks.

[Phil Hobson]

As above Brian, Wedi, Marmox etc are insulation boards Hardie, no more ply etc. Are cementitious backer-boards

[Sir Ramic]

You could read this
Insulation boards

[Bri]

You could read this
Insulation boards

Thats alot of numbers! I think I'm more educated now!

[Sir Ramic]

Thats alot of numbers! I think I'm more educated now!

I think this actually made it easier for me to understand
However, in real life comparisons with cable underfloor heating the following approximate results were observed:

1. Onto bare concrete slab – took about 3 hours to reach max temp of 24°C.
2. Onto No More Ply 6mm – took about 40 minutes to reach 24°C and 3 hours to reach max temp of 27°C.
3. Onto Beavaboard 6mm – took about 30 minutes to reach 24°C; temperature 29°C at 3 hours and still increasing.

[tim_r]

Do any of the insulating boards have the strength of hardi backer? Is it best to use both when overlaying a wooden floor to have UFH and then tiles?

[Bri]

Do any of the insulating boards have the strength of hardi backer? Is it best to use both when overlaying a wooden floor to have UFH and then tiles?

Hardi boards aren't used to add strength, just a suitable surface to tile on. If the subfloor is not stable the hardi boards won't cure the problem.

[aph257]

I would get the strenght from WBP ply (25mm) then add the insulation board.