Warm water underfloor heating

[holedigger]

Hi All

I have fitted a warm water underfloor heating system (JG), its on the grond floor laid over 50mm of celotex between dummy joists with a biscuit screed thats 20mm thick with a 18mm P5 chipboard screwed at 300mm intervals. I am now ready to tile, whats the best tile adhesive to use? By the way the tiles are 600*300mm natural stone and the biggest room is just under 44 m3.

 

[DHTiling]

I would apply ditra fixed with BAL fastflex then tile using BAL rapidset flexible.

There will be quite some expansion there , so have you installed movement joints.?. If so these will need to be carried up through the installation.

I think the Ditra will be the way to go especially seen as it is stone you are working with.......

I haven't heard of a wet floor heating system done that way before.....100mm screed would have been my option, much more stable base to tile too.......but Ditra being an uncoupling membrane then it will be the best way to go .IMO..........
As long as the subfloor is well fixed and you say it is.......

good luck........

 

[holedigger]

Hi Dave

Thanks for the reply, the dummy joists are fixed to the existing pad very well and there is 1 to 2 mm of room for expansion between every P5 sheet (2400*600). The biscuit screed is only 20mm thick as it acts as a heat sink, with this system the overall floor is only increased by 70mm without tiles as its over the old floor slab. Also where is the best place to get the materials from as you can tell i will need a lot, the total tile area is around 102m3.

 

[DHTiling]

I would normally recommend CTD but for that amount of Ditra it will be cheaper to buy 30 mtr rolls and you can get very good prices off the web.........if you want i could find you a good supplier or maybe one of the members will know one..i remember someone saying they could get it for about £6 a mtr if bought at 30 mtrs a go...........but you could still get the adhesive etc from CTD if you so wished............good luck mate and will you let us know how you get on........