the order of under floor heating

[cowgomoo]

Hi Guys and Girls, I am about to commence a first floor bathroom floor and the client wishes for ufh. So out with the laminate, out with the knackered floor boards, in with the reinforcing joists and 18ml ply then.... would it best be decoupling membrane then ufh mat then tiles ? Also the sensor cable protective sheath - are there any that aren't half a mile thick !! Which membrane and ufh mats do you prefer ? Cost isn't a particular issue but there is no point buying what you don't need , oh and before I forget - tiles to be laid are porcelain 600 x 600 over about 4m2. Thanks in advance, Cow

[david campbell]

i wouldn't bother with a membrane but would use 25mm ply and i would use a flexible s.l,c over the mat

[timeless john]

If you've got any joints in the plywood I'd use a decoupling membrane (ditra or similar).
The ufh system I like is Thermonet.
Always put the condurit into the floor as most programmers only give 1/3 year warranty.

[cowgomoo]

Thank you Timeless, I have formed a picture in my head now, there will be joints in the ply and I think I was always using a membrane so it was just the order of things ! Have done plenty before but always onto concrete screed. This will be my first real prestigious private job of full bathroom design so dont want to muck it up

[dilz000]

what about 18mm ply then backer board? Can you cover the cost of ditra into your price?

[timeless john]

It's only 4sq mts or 11 @ 600x600mm tiles so I don't think the ditra or similar will break the bank!

Good luck with the job and don't forget to ring if you need any input - and do post some pictures.

[cowgomoo]

Thanks Timeless, cost of ditra is not the issue - it has to be used it was just the ufh, some are a lot more dosh than others is all and as it was just to take the chill off the floor as opposed to heating the room up I was looking for advice in that area more than anything else. Will post some before / during / after pictures for y'all.