Wet UFH on Block & Beam and Joists...

[Dumbo]

That's a very good point, I'll speak to the builder...

If it's not built yet it can be done as it's all about the ground work. I can't imagine there is a tiler on here that would prefer to tile to timber suspended floor instead of solid screed .

 

[J Sid]

start with a level subfloor
glue 50mm ProWarm™ XP-PRO Insulation Board - Electric - Insulation Boards - http://www.theunderfloorheatingstore.com/insulation-boards/electric/xp-pro-insulation-board
then glue
ProWarm™ 18mm Low Profile Solid floor panels - Water - Insulation Boards - http://www.theunderfloorheatingstore.com/insulation-boards/water/prowarm-18mm-low-profile-solid-floor-panels
fit pipes
Ditra
tile
finished floor height 80mm

 

[curtly]

Thanks for the responses guys, lots of food for thought.

Its looking like a toss-up between the Nu-heat LoPro Max with a low profile screed finish and the ProWarm solid floor panels.

I like the idea of the Screed finish for conductivity and being fully sealed base but reckon the solid panels would add a bit more rigidity 😕

 

[Chalker]

Nu heat Lo pro max. Has the best kW per m2 for a 25mm total build up.

In this case, though. I would recommend an odd apraoch!!

Firstly I would bin the timber joists and fit a block and beam floor.
Set the level of this floor 160mm down from finished floor level . Fit 100mm insulation as per building regs.
Then for the existing floor ( bear with me) I would fit 25mm insulation ( I know it's not perfect, but it's the best that can be done). This will line up with the new extension floor. Cover with membrane and fit standard wet underfloor.
55mm screed on top.

Somtimes bending the rules works. Not perfect, but works.

 

[curtly]

Nu heat Lo pro max. Has the best kW per m2 for a 25mm total build up.

In this case, though. I would recommend an odd apraoch!!

Firstly I would bin the timber joists and fit a block and beam floor.
Set the level of this floor 160mm down from finished floor level . Fit 100mm insulation as per building regs.
Then for the existing floor ( bear with me) I would fit 25mm insulation ( I know it's not perfect, but it's the best that can be done). This will line up with the new extension floor. Cover with membrane and fit standard wet underfloor.
55mm screed on top.

Somtimes bending the rules works. Not perfect, but works.

Interesting, that was my own thoughts at the start, is 55mm screed the minimum acceptable as I've got tiles to add to that 80mm ?

 

[Chalker]

50-55 is minimum for tiling onto. Speak to a screed supplier, they can add fibres to strengthen it. Then it can be reduced by a bit.
@Ajax123 on here is the forum expert on here.

 

[Dumbo]

Calcium sulphate screeds can go in thinner than sand cement screeds .

 

[Swindiff]

Gyvlon Thermio+ can go down unbonded onto insulation at a thickness as low as 35mm. I had it installed in my kitchen on top of 50mm celotex. My minimum thickness was 36mm, maximum was 52mm and average was 48mm. More than pleased with it and extremely responsive to the heat in the UFH pipes. I can start to feel it coming through the floor in less than 30 minutes with porcelain tiles laid on top. I had heard all the stores of UFH having to be run pretty much constantly because it takes forever to heat up and cool down, not with this stuff, my UFH gets turned on and of as I would have with the radiators.

Gyvlon Launches New Thermio+ Screed; EasyFlow to Supply Nationwide | EasyFlow - http://www.easyflow.org.uk/news/thermio-screed/