Looking for guidance on mixing floor materials.  New house will include a habitable space above the garage that includes a bathroom, kitchen and living space.  Headroom is limited so trying to minimise the floor build-up onto the web joists.  I've settled on electric UFH for the bathroom (which will also have a towel rail)  but need to connect the living area into the ASHP with UFH (  as electric would be too expensive as the primary source of heat.  Because of the web joists I understand I cant use the spreader plates under the joists (due to return bends needing to be notched into the joist) and i probably don't have enough headroom to add something on top of the 22mm Caberdeck flooring (glued and screwed to joists).  Prowarm (and maybe others) offer a 22mm T&G chipboard floor that is pregrooved for 16mm UFH pipes which seems to offer a hybrid type solution. So my question is could you mix the two flooring systems with Casberdeck under the Bathroom & Kitchen and Prowarm chipboard under the living space?  

 

Any advice much appreciated.

No but you don’t need to notch the joists, you just feed it through the web and tack back up. Insulate the bends with climaflex and insulate under the pipes well with fibre insulation.
 

Easier and quicker than messing about with the overboard systems. 

32 minutes ago, cbk said:

Prowarm (and maybe others) offer a 22mm T&G chipboard floor that is pregrooved for 16mm UFH pipes which seems to offer a hybrid type solution.

I’m wondering whether these actually  work well in practice. Chipboard doesn’t sound like it has the right properties to deflect heat upwards, or is the idea that you install spreader plates onto the pregrooved chipboard.

11 minutes ago, Adsibob said:

I’m wondering whether these actually  work well in practice. Chipboard doesn’t sound like it has the right properties to deflect heat upwards, or is the idea that you install spreader plates onto the pregrooved chipboard.

Yes the installation detail shows you need to install the spreader plates as well before installing the pipes.

47 minutes ago, PeterW said:

No but you don’t need to notch the joists, you just feed it through the web and tack back up. Insulate the bends with climaflex and insulate under the pipes well with fibre insulation.
 

Easier and quicker than messing about with the overboard systems. 

Thanks this is good to know. I was worried this might create a problem with airlocks but i guess not.  Much simpler solution and I can stick to caberdeck throughout.

 

A related question. As I plan to put engineered timber boards over the caberdeck/UFH will this need to be glued down or can it just sit on the caberdeck?  Maybe with a VCL layer?

Depends on the timber - some need to be glued, others float.