Levels of floor.

[curlewhouse]

So,  I'm putting in UFH on top of a beam and block floor and so the build up is: beam and block, sand blinding (about 1-2mm) DPM which is turned up the walls at taped to the DPC, then 100mm insulation then polythene. Looking at it now I'd like to uprate the insulation from our original spec, but to do this would mean the screed would be up higher than the outside DPC and would be thus up beyond the blocks on which the SIPs construction stands and albeit separated by polythene and insulation permieter, up alongside the OSB board on the SIPS - is this OK? Is it even relevant? I can't find anything to say it is or it isn't, (it leaves 76mm from top of the insulation slabs to DPC level at present but 130 to the bottom of the door openings).   

[PeterW]

Is that 100mm PIR..? You could just change the product to a PUR foam or even vacuum panel and get better insulation for the same build up but with no issues of breaching the DPM

[oranjeboom]

Had a similar scenario where my concrete/screed layer was going to be above my sole plate. I was simply going to ensure that my DPM lapped up against the side the sole plate and up the OSB wall. Don't forget the perimeter insulation. In the end I went with a mix of PIR and EPS so my floor is going to end up level with the blocks that my SIPs sit on. Also consider cold bridging around this area and how to minimise.

 

As for vacuum panels, aren't they prone to losing the vacuum over time? And also bloody £££?

[curlewhouse]

At the height of the door thresholds in the SIPS construction they are actually over 100mm above the DPC so my floor build up would have to go that high anyway somehow  (I've already got the full UFH kit with the perimeter insulation etc. from Wunda) - I cant think of a physical reason why my screed should not be higher than the blocks, given that the perimeter insulation should absorb expansion movement thus not transferring it to the SIPs, but it just sort of feels odd/wrong. No advantage in making it thinner PeterW as if anything I need to take up more space in the build-up as even with 100mm PIR in place I've got about 150mm still to reach the door thresholds. Given the height of the door thresholds (they have the sole plate then another piece of wood on top, so the SIPs are in effect on  two soleplates so to speak) actually, I'm not sure I've actually got any other option than building the floor up other than maybe remove the top layer of wood in the doorways. (but presumably its there for a reason).

Edited September 5, 2017 by curlewhouse

[oranjeboom]

3 minutes ago, curlewhouse said:

......... Given the height of the door thresholds (they have the sole plate then another piece of wood on top, so the SIPs are in effect on  two soleplates so to speak.).

I had the same, the sole plate itself and then another timber the same height again. I cut both out at the doorways to reveal the blockwork which then became my DPC level. Once the SIP panels are insitu and fixed I don't think the sole plate at the doorways have any purpose. They aren't holding anything in place.

 

So what height is your blockwork wall that your SIPs sit on?

[curlewhouse]

Its 200mm from the beam and block floor to top of the blocks the sole[plate sits on.