6mm insulation board under hardierbacker for UFH?

[owen werakso]

Hi - This is my first post so i should start by saying thanks for all the info i have got from this site in the past years.

I have bought electric UFH mats along with 6mm insulation boards.

I am looking to tile my 4m bathroom floor which has t&g wooden floor. I will screw this down but looking for advice on how to build up the layers to the tiles.

I was thinking Flexible tile adhesive to bed insulation boards then tile adhesive again to bed 6mm hardiebacker board and screw threw both into the floorboards.

Then attache the UFH mat to the HBB and layer more flexible tile adhesive to tile on top.

I don't want to build up the height and trying to avoid pulling up all the existing floorboards to replace with ply.

will this be a suitable build up for floorboards/ UFH and tiles

Cheers

 

[Simon Dale]

Don't forget uncoupling mat. 12mm insulation board would be enough for 4mts. No need for both.

 

[Flintstone]

What tiles are you using?
You don’t need 2 layers on the floor, 6mm hardiebacker on it’s own is fine, or 10mm insulation board. No uncoupling needed unless your fitting stone

 

[owen werakso]

Thanks for the heads up - but i have already bought 6mm insulation can i just use this instead of the suggested 10/12mm? - i am using ceramic 300x300 tiles.

As hardiebacker has no thermal properties i would presumed i would need the 6mm insulation in the build up somewhere, hardiebacker or not.