Mosaics over electric UFH & chipboard?

[J Sid]

think you need to fit impey waterguard to the tray first as tile adhesive or SLC will not stick directly to the tray and to seal the gulley.
I'd fit 6m insulation boards as above then waterguard to tray over lapping the boards where they stop by the tray.
fit ufh and then SLC over these, making sure it doesn't all run down the drain with a expanding foam dam.
then tank / waterproof the hole area, floor and walls with a waterproof and uncoupling membrane https://www.isomat.gr/wp-content/uploads/2015/12/e-waterproofing.pdf

 

[SJPurdy]

I would check with board manufacturer re. number and spacing of screws/washers. 300mm centres sounds a bit excessive to me. The last data sheet I had from Wedi (it may now be out of date) stated to fix the Wedi board to the chipboard with flexible cement based adhesive (after applying an appropriate primer and letting it dry). Then when dry fix using the screw/washer system at a rate of 5 per m2 and fitted no closer than 30mm from the board edges. Washers screwed down to the surface and then lightly tapped with a rubber mallet to drive flush with the surface and then the screws retightened.

 

[Dan]

Have a word with www.uheat.co.uk you'll get a discount for being a forum member, and a very good discount if you get a trade account with them.

 

[Ben R]

think you need to fit impey waterguard to the tray first as tile adhesive or SLC will not stick directly to the tray and to seal the gulley.
I'd fit 6m insulation boards as above then waterguard to tray over lapping the boards where they stop by the tray.
fit ufh and then SLC over these, making sure it doesn't all run down the drain with a expanding foam dam.
then tank / waterproof the hole area, floor and walls with a waterproof and uncoupling membrane https://www.isomat.gr/wp-content/uploads/2015/12/e-waterproofing.pdf

Thanks. So I'd essentially be tanking/waterproofing it twice? Once with the Waterguard & again with the Isomat?

 

[Old Mod]

I would check with board manufacturer re. number and spacing of screws/washers. 300mm centres sounds a bit excessive to me. .

Could well be correct Steve, I just had Schlüters recommendation in my head when I wrote it, they recommend 250mm centres.

 

[J Sid]

Thanks. So I'd essentially be tanking/waterproofing it twice? Once with the Waterguard & again with the Isomat?

all depends on how you do the water guard. if you are just doing it on the deck and not doing upstand round tray and corners then I would use a uncoupling and waterproofing membrane after the ufh and slc is done and take this over the whole floor , up walls in wet area and do pipe outlets, also turn this membrane up 50mm behind skirting/tiles outside the shower are.