Hello,
This is for a new build semi-subterranean stone clad residential extension. I'm designing something that seems to be both challenging principles and products available, not what I hoped for!
The proposed build up: I wish to have a 300mm dp turf roof, then roof membrane (probably Bauder), then Beam and Block floor (or rather the most slender structural roof support for the turf roof's dead & live loads - does B & B do this?). I want then to affix steel MF or resilient strip galv. steel framework ot top had section to the underside of the cold roof into which to insert & tape PIR insulation (of the thickness to achieve better then 2016 Part L1B), a vapour control layer and then plasterboard & finishes.
My primary objective is to have a completely non-cold bridged internal envelope and not have a thick wall build ups for space reasons. For example I want to support the roof structure on the already thick stone & blockwork external wall leafs and have SIPs or internal wall insulation on batts, again no timber at all. If I had a warm roof, as all the flat roof products on the market seem to steer me towards, then there would be a parapet to roof cold bridge all along the perimeter where the roof is supported by outside walls.
I understand the problems of unvented cold roofs are to do with condensation and primarily the bad rep is with timber roofs. I'm avoiding any timber in the cold roof (and in fact as little an air gap as possible). I want to make this building have as little air leakage as possible, almost passivhaus, and it will have MVHR. Yes there needs to be really good tight construction discipline to limit air gaps and yes it will be overhead which is harder but not impossible especially as all the units are light.
So what's the problem and why can I find no insulation products BBAs from the primary suppliers in the UK? Or have I just not found the right one yet?
Any opinions welcomed, cheers.
This is for a new build semi-subterranean stone clad residential extension. I'm designing something that seems to be both challenging principles and products available, not what I hoped for!
The proposed build up: I wish to have a 300mm dp turf roof, then roof membrane (probably Bauder), then Beam and Block floor (or rather the most slender structural roof support for the turf roof's dead & live loads - does B & B do this?). I want then to affix steel MF or resilient strip galv. steel framework ot top had section to the underside of the cold roof into which to insert & tape PIR insulation (of the thickness to achieve better then 2016 Part L1B), a vapour control layer and then plasterboard & finishes.
My primary objective is to have a completely non-cold bridged internal envelope and not have a thick wall build ups for space reasons. For example I want to support the roof structure on the already thick stone & blockwork external wall leafs and have SIPs or internal wall insulation on batts, again no timber at all. If I had a warm roof, as all the flat roof products on the market seem to steer me towards, then there would be a parapet to roof cold bridge all along the perimeter where the roof is supported by outside walls.
I understand the problems of unvented cold roofs are to do with condensation and primarily the bad rep is with timber roofs. I'm avoiding any timber in the cold roof (and in fact as little an air gap as possible). I want to make this building have as little air leakage as possible, almost passivhaus, and it will have MVHR. Yes there needs to be really good tight construction discipline to limit air gaps and yes it will be overhead which is harder but not impossible especially as all the units are light.
So what's the problem and why can I find no insulation products BBAs from the primary suppliers in the UK? Or have I just not found the right one yet?
Any opinions welcomed, cheers.
