U/F heating mat question.

[jollyroger]

I was called out to investigate a leaking wetroom floor and was wondering how many of you would install a heating mat over a shower tray former ?

 

[Qwerty]

I have in the past but mostly tend to tile the floor leaving the former unheated.

Was this the cause of the leak you saw?

 

[jollyroger]

Wedi tray and Wedi board on the walls. All the tanking looked good, however, the self adhesive waterproof tape around the perimeter of the tray had de-bonded from the tray itself. Not sure if the heating has caused this.
Water has got under the tape and leaked onto the ceiling below. The tiling was a joke, 600mm x 300mm porcelain tiles all dot dabbed to the floor. Tiler has only cut 3 of the diagonal envelope cuts and didn't bother with the 4th, unbelievable.
Point is, all the tanking looked good apart from the tape de-bonding and I wonder if the heating might have caused it to de-bond from the tray.

 

[Alphadock]

Like plan Tec, I leave the tray/wet area unheated. (Is it ok to put electric ufh in the wet area?)
I don't think the heat would affect the tape, but that's just opinion. Maybe ask the ufh company and tape company about suitability.
If the tiler couldn't be arsed to actually cut tiles then he probably couldn't be arsed to peel the backing off the tape as well!

 

[Dash J]

I was of the impression you weren't meant to put ufh on the tray,I have never done so anyway
its a no brainier where the problem is coming from if the tiles are spot fixed and there is no proper mitres.total lift and re-lay Imo

 

[SJPurdy]

I have asked UTH manufacturers, in the past, if ok to use on shower base wet area and they have said yes. I know I have done it with both Warmup and Devi, at the customers request (it wouldn't be my choice), and have had no problems.
Clearly bad quality tiling in this case and I also am suspicious of the self adhesive tape, as the ones I have tried do not stick very well.