UFH, decoupling issue

[Steve R]

Hi Guys,
I'm after a little advice ? I'm just in the process of pricing the following job, the spec is 600x600 callibrated slate tiles on a split substrate (sand and cement screed/chipboard). The screed has pipework in it and the chipboard will have polypipe system overlay on it (approx 30 sq mtrs), the client would prefer not to have any expansion joints (total area approx 100 sq mtrs: 4 rooms). The solution i would assume would be to decouple the lot, having very limited experience of decoupling systems my questions are, which would be best Ditra ? G-Mat ? or would i be able to get away with Plasticply ?. Secondly am i ok to fit decoupling matting directly to the Polypipe fibre board ?
Cheers
Steve

 

[The Legend; Phil Hobson RIP]

Hi Steve and welcome, I would make sure there is no deflection in the chipboard then make sure the polypipe system is screwed down well, then encapsulate in slc (at least 3mm). If you need to bring the screeded areas up slc to same height as polypipe+slc.


Different substrates need expansion joints, where solid floor meets timber expansion joint is needed, as different substrates are prone to different stresses.


I would go for Ditra or new Dural, forget the plasticply imo, 100m2 is way to big without expansion , make sure you install them in the doorways and perimeter , as well as the recommended min bays, make sure you check out the bay sizes with ufh. hope this helps

 

[Dan]

Even with decoupling you need expansion joints I believe?

The rooms will heat and cool at different rates. Don't do it without expansion joints. You can make some pretty hidden expansion joints providing the tiles are not being fitted brickbond style or something else that wouldn't allow for a straight line like opus romano or whatever it's bloody called.

Wait for the lads to respond, but I think I'm right there.

Edit: Phil beat me to it!

 

[Spud]

schluter do an expansion joint trim thats only 5mm wide schluter Dilex bws , it looks really nice very subtle it will be unnoticeable with slate tiles imo

 

[The Legend; Phil Hobson RIP]

That must be a first Dan, my slow typing must be improving.:lol::lol::lol: