Stud walls then screed?

[Ouch77]

What order is preferred for walls and screed (with UFH)?

I'm using a wet UFH system with 75mm screed over membrane and PIR insulation (PIR is already laid). I have a stud wall (plasterboard over OSB over timber frame) that needs to go in. I can see this going 2 ways:

Walls first - makes the screed pour a little harder, as it's not a continuous space and levels may be a little awry. I'll need to clad the lower section of the wall to get the right position/spacing for the perimeter expansion layer. Harder to secure wall base to PIR - I don't really want to fix to subfloor due to potential cold spots & thermal bridging.

Screed first - no thermal break in screed between rooms, so possible cracking due to uneven expansion. 75mm screed may not be strong/deep enough to fix wall base into, exotic fixing required?

I'm not that concerned about hitting the UFH pipes as they'll be laid sufficiently clear of the walls, and I'll pass between the areas in the handy doorway by the manifold.

I think regardless I'm going to need some clever way of securing the sole plate of the wall to the insulation/screed - glue perhaps?

Suggestions and personal experiences welcome..

 

[Wayners]

No my area.

All I can say is I've seen stud walls built over all sorts. Insulation with sheets of wood over. Concrete. Self leveler ect
No problem
I guess sort the floor then build the stud wall

 

[noseall]

What order is preferred for walls and screed (with UFH)?

I'm using a wet UFH system with 75mm screed over membrane and PIR insulation (PIR is already laid). I have a stud wall (plasterboard over OSB over timber frame) that needs to go in. I can see this going 2 ways:

Walls first - makes the screed pour a little harder, as it's not a continuous space and levels may be a little awry. I'll need to clad the lower section of the wall to get the right position/spacing for the perimeter expansion layer. Harder to secure wall base to PIR - I don't really want to fix to subfloor due to potential cold spots & thermal bridging.

Screed first - no thermal break in screed between rooms, so possible cracking due to uneven expansion. 75mm screed may not be strong/deep enough to fix wall base into, exotic fixing required?

I'm not that concerned about hitting the UFH pipes as they'll be laid sufficiently clear of the walls, and I'll pass between the areas in the handy doorway by the manifold.

I think regardless I'm going to need some clever way of securing the sole plate of the wall to the insulation/screed - glue perhaps?

Suggestions and personal experiences welcome..

Screed first.

 

[endecotp]

75mm screed may not be strong/deep enough to fix wall base into

It’s fine.

 

[^woody^]

A course(s) of AAC blocks/bricks that is level with the FFL, then the partition built on that.
Ideally, the UFH would be zoned to the rooms.