Studwork / UFH

[Redoctober]

On 17/11/2020 at 13:51, Conor said:

 

What are you studs built up on? Concrete sub-floor? Mind sharing the details?

Hi sorry for the delay in getting back to you. I'm unable to check my photo library at the moment but from memory, the studs went into the base then the insulation went down, followed by the UFH. The liquid screed eastern poured. ?

Edited November 18, 2020 by Redoctober
Wrong info!!!

[climbinggeorge]

I had planned to get screed down, then build studs directly on top.  This was possibly because I was just thinking in layers.
However due to delays its now looking more likely to try and crack on with stud walls then pour the screed around them.

For this a friend had suggested doing a layer of blockwork then pouring screed and then building the studwork on top of that.  I wasn't sure if the blockwork can sit directly on the insulation or if it needed to go to the beam/block but thought this would have a cold bridging risk?

Have attached a very technical drawing, with my original thinking on the left and the 2 alternatives on the right if anyone can advise

[JulianB]

Another bump for this thread!

 

Interested to know what build up people go with if stud walling before screeding! We're in a bit of a catch 22 as we would ideally like to put up partition walls and the staircase after we screed, however are not entirely sure if we will be able to squeeze all the ASHP / UVC gubbins under the staircase and hence in an ideal world would like the staircase to be in place to know the exact placement of the UVC etc in order to better position the UFH manifold for that floor which will also live in this area (DOH!). If we do go down the stud walls on B&B floor prior to insulation / screeding, would there be a need to build up the soleplate to above screed level, or would you simply shutter with ply on either side of the stud partition, and leave the sole plate buried some 150mm? I guess the benefit of this approach would be that you can then fit some rigid PIR strips to make up the height from top face of sole plate to top of screed, and then place noggins at the screed level to act as the psuedo sole plate for fixing boards and what not to ? For reference my build up will be 100-120mm PIR and 50mm screed.  

 

Also, on another note, has anyone ever installed partition walls to the top face of the insulation layer, as presumably once the screed has been poured they aren't going anywhere?

[Adam2]

Hi Julian, I'm planning on using marmox as the bottom course of blocks for my internals walls that are built off my concrete slab - other products out there. In your option with the block on the slab this would reduce your cold bridge. Your SE could confirm if that is OK and if you could then have a course of blocks on top ready for your studwork or if you needed  a connection through to the B&B - not sure why you would if just timber stud walls though. As you have B&B beneath there may be concerns re movement transferring to the walls if built directly on this unless the wall is over a supporting structure beneath that - just speculating really - would check with SE

 

Having your UFH pass between rooms means you lose some ability to control individual room temps - may not be an issue but just noting that in case of relevance. You can't of course do this with the 2 options you have.

[JulianB]

13 hours ago, Adam2 said:

Hi Julian, I'm planning on using marmox as the bottom course of blocks for my internals walls that are built off my concrete slab - other products out there. In your option with the block on the slab this would reduce your cold bridge. Your SE could confirm if that is OK and if you could then have a course of blocks on top ready for your studwork or if you needed  a connection through to the B&B - not sure why you would if just timber stud walls though. As you have B&B beneath there may be concerns re movement transferring to the walls if built directly on this unless the wall is over a supporting structure beneath that - just speculating really - would check with SE

 

Having your UFH pass between rooms means you lose some ability to control individual room temps - may not be an issue but just noting that in case of relevance. You can't of course do this with the 2 options you have.

 

Thanks Adam! I had actually looked at some marmox products when we were building up the perimeter wall off the beam and block...good stuff! Will check with SE...wondering if anyone has ever gone sole plate straight to B&B (with DPC in between ofcourse) as I can see a benefit to then filling the void it creates with insulation again (to screed level). Am I at risk of rotting the soleplate in that scenario?