Wet room over wet underfloor

[stanbalder]

I want to install a wet room in a new build we are doing. The wet underfloor heating pipes are fixed on to the upper surface of Kingspan and then a 70mm screed is applied.

It doesn't make that much sense to install a de-coupling membrane to waterproof, when I could simply epoxy the screed and tile straight on to that.

Is that daft? Anyone have any strong opinions on this?

Cheers

Stan

[whitebeam]

If you get any lateral stress the epoxy won't stop you getting cracks in the screed, then thru to your tiles...

A de-coupling membrane will save you some heartache with any stress in your screed which will not crack your tiles.

[Ajax123]

ditto Whitebeams comments. If the screed cracks (and at 70mm presumably running to a fall would make this a real possibility) then the epoxy will also crack. That will allow water into the screed once the tile cracks. Once this happens a whole world of pain can open up. I suspect that uncoupling would actually work out cheaper as well.