Wet room floor with heating installation issue

[David H]

Hi - I have made a boo boo. I have stuck the AquaMat100 electrich heating to the RIW tanking membrane without removing the backing film. The backing film has stuck to the RIW like you wouldnt believe, so I cant remove it. Do you think it will be ok to tile over the heating mat with the plastic film in place? The floor is 5m2 and the tiles are porcelain 600 x 300 with an AquaDec shower base. Question is really, will the tile adhesive be ok on the plastic film, the film is cover with a fibreglass crisscross mesh, and then there is the heating element. Floor is supended timber 1st floor but pretty firm, no flexing apparent. 18mm chipboard was overlaid with 3.6mm ply and screwed every 100mm. RIW is well stuck down. Any advice?
😳

 

[Gazzer]

Not good, IMO its gotta come up.

 

[Dan]

You'd be relying on the plastic film to stay in place when the heating is being used, which it wont, so your tiles wont actually be stuck to anything if you tiled it like that and used it. They'd come up anyway.

Best not to ruin your porcelain tiles or heating system by tiling it like it is. It will fail. Get it up while it's cheaper to do so.

 

[Rookery]

I'd also be concerned about the 3.6mm ply overlay.

 

[David H]

Someone has suggested that it would be no different than tiling over plastic ply (which I had never heard of) and it is apparently ok to tile over plastic ply which is an adhesive plastic sheet about 600 sq. which is stuck to the floor under tiling? Using a flexible tile adhesive and grout?

 

[Time's Ran Out]

Never used plastic ply myself, but as you've stated it's stuck down with a flexible tile adhesive and nor just a backing film. You obviously had concerns to ask the question so bite the bullet and go with Forum advice.