Under floor heating on suspended wood floor

[Pez]

Hi folks
I've got a suspended wood floor in my kitchen that currently has tiles on 6mm ply on top of the floor boards. I'm pulling the tiles up cos they're old and lots are broken and want to put electric under floor heating down then slate tiles.
I've been reading and know the ideal would be insulating plates on the boards/ply and then the heat mats but I'm going to be pushed for height as I don't want to have to pull out all the kitchen units.
Is it possible to stick the ufh mats directly onto the ply and tile straight on top or do I need some slc before tiling? The heating would be a second source of heat as I already have a radiator that I am keeping so having the most efficient insulation isn't my primary concern. The floor is solid too, the broken tiles are from when they were lifted when installing the heating.
To muddy the water further, I am thinking of continuing the heating into the hall which is concrete at the same level as the ply in the kitchen. Is there a problem in putting the ufh straight onto the concrete? I'm not too bothered about having it in the hall, I can finish it in the kitchen if it is going to cause problems.
Any advice would be great!

 

[Andy Tiler]

Personally I wouldn't put undertile heating straight onto ply! But you can?
You will need the low wattage heating probably 100watts ps mtre if you go on to ply!but you will hardly feel it.
Onto concrete you will need thermal boards, otherwise you will be heating the slab up before the heat rises..
make sure you install a movement joint where the two substrates meet!!

 

[Rookery]

As a compromise and as height is an issue here, I would take up the 6mm ply and replace it with 6mm insulation board such as Marmox, glued and screwed, then put the ufh on that.

 

[Pez]

Cheers guys, will look into that marmox stuff and go down that route

 

[Uheat - Keith]

Good stuff from guy above again.

Our Elektra UT10 Underfloor Heating Cable is only 2mm thick, but as all others, onto ply will only be a warm floor system not a heating system.


Warm regards,