Non Flex SLC on UFH, help please!!

[carolage]

Hi,

Flooring out my wetroom at home, 25mm osb3 with 10mm wedi backer board glued and screwed.
Electric underfloor heating matts went down and i decided to go the SLC route to avoid disasters, sadly
misread the back of the pack of mapei buildfix hp3 performance, and it states it is useable on hot water underfloor heating
but no mention of electric. There is no mention of latex or flex either.

From reading previous posts I can go down the ditra/mapetex uncoupling membrane route to cover my fear of the screed cracking, which I may do anyway, would there be any point priming the SLC and skimming a 5mm flexible SLC on top to hold it all together? I am about 5mm below where I need to be to reach the shower deck height so have room to do it.

Any input would be gratefully received,

 

[White Room]

If it goes with water ufh then why not electric....

 

[Qwerty]

If it goes with water ufh then why not electric....

Exactly. The temperatures both systems run at are similar.

 

[carolage]

I rang Mapei UK who don't recognise the product, it is french and I am in France, but they were very helpful. Rang Mapei France, they couldn't tell me anything about the product they sell and the advice was to turn on the UFH before tiling to see if anything cracks - filled with confidence.

If electric and water UFH run at the same temp would water need a thicker screed to cover the pipes as opposed to electric and therefore be more stable??

I just don't have confidence in the SLC, it does really say enough on the pack, it didn't cost as much as it probably should, LOL, and all other UFH screeds seem reassuringly complicated - latex, 2 pack etc. Am I making a mountain??