low thermal resistance Cement board over UFH?

[Shai]

Hi all, some advice would be greatly appreciated.

So the builder messed up in the loft during a major renovation in our house.

In short, we have UFH boards laid out throughout the loft room and the en suite. At this point, the polypipe type foam boards and attached pipes are all on the same level and flow through to the en suite. However, due to a major misunderstanding, the finished laminated floor in the room is about 14mm lower than the finished tiled floor in the en suite.

We are not able at this stage to lift the UFH and lay plywood underneath to bring the floor level up. Its a long story but just not possible at this point.

So, im looking for some damage limitation options. The builder lifted the laminate floor up and we are now down to the UFH boards and inserted pipes. Does anyone know of a decent cement board type product that will have a high thermal conductivity properties like this: High Performance FLAT Dry Screed Overlay Cement Boards for underfloor heating - https://www.thefloorheatingwarehouse.co.uk/acatalog/High-Performance-Dry-Screed-Overlay-Cement-Boards-for-underfloor-heating--CB_HiDeck18.html but 12mm rather than 18mm. I just want something that will allow some of the heat to get to the floor. I know its not ideal, especially as laminate floor is not great for UFH anyway so adding an unnecessary layer just makes it worst but I'm at a point where I just need to make the best of a crappy situation.

Any other ideas will also be appreciated. I don't really want more than a 2 or 3mm height difference between the rooms

 

[Waluigi]

I’m pretty sure Marmox do something. Let me have a quick look into it.

(Not to be confused with the marmox foam boards. The type I’m thinking of go above UFH, not beneath)

 

[Shai]

thanks. Cant seem to find anything on their site which is suitable. Any other ideas? Is just plain cement board be ok for this?

 

[WetSaw]

Hardiebacker or any brand of cement board will do the job.

 

[Waluigi]

I spent a while looking but can’t find any info on the marmox system.
It might not be marmox.
As PDC says, a cement board might work as these boards get hot theougout the board whereas a foam board will stop the heat passing through.

 

[Chalker]

Fermacell flooring

 

[Uheat - Jake]

You'd want a screed board to go over the top, we've supplied HiDeck 18mm board before. You don't want to go for a Tile Backerboard with a cement coating as they're used as insulation to stop the heat travelling down, therefore this would stop the heat travelling up.

 

[Dumbo]

You'd want a screed board to go over the top, we've supplied HiDeck 18mm board before. You don't want to go for a Tile Backerboard with a cement coating as they're used as insulation to stop the heat travelling down, therefore this would stop the heat travelling up.

Surely that doesn't apply to hardie and nmp .

 

[Uheat - Jake]

Surely that doesn't apply to hardie and nmp .

I'm not to familier to the Hardie or nmp, but if it has the layer of blue insulation in it then it's classed as a backerboard which insulates. A screed board is just a cement board with no insulation layer between it, over the ufh this would act as a screed and contracts heat and then gradually release it.

 

[Waluigi]

Hardie, NMP and Aquapanel heat up across the whole of the board compared to a foam board which is designed to stop heat passing through it.