Pops has asked me for help insulating his solid walls. (I've done K18 on 2x1 battens in my 30's house few months back and was such an easy job - Apparently this now makes me the family expert on all things insulation!)
Anyway, he over-ordered on the GA4070 for his hoooge loft conversion a few months back (done by a local builder) and has about 6 sheets left -just enough to do walls in 2 bedrooms on ground floor of his bungalow. I've double checked the calcs and min thickness on insulation for his walls is 60mm (like I have used).
He's only looking at doing this because he's got all this extra material lying around otherwise wouldn't bother.
Now obviously from the installation instructions this particular insulation slab type is used in stud walls/between roof rafters/in cavities on new build so requires mechanical support of some kind-however making a studded frame drastically raises the U value above the 0.3 required by BC. Am I OK to achieve a similar composite slab to my own K18 in the following way?:
1. 2x1 vertical battens fixed to wall to create a 1" air gap (and the extra 0.6 on the compsite slab R value).
2. Put the insulation board up
3. 12.5mm plasterboard on top then 100mm drywall screws through the whole lot into the battens.
4. 3mm plaster skim
Sound OK?
If an additional vap barrier is required where in the composite should it go? Would adding this affect the purported 0.6R gain of the foil face on the insulation board against the air gap layer?
(Or should I just tell him to try and sell the leftovers and buy K18 if he's that desperate to insulate like I did?)
Thanks for advice
Dave
Anyway, he over-ordered on the GA4070 for his hoooge loft conversion a few months back (done by a local builder) and has about 6 sheets left -just enough to do walls in 2 bedrooms on ground floor of his bungalow. I've double checked the calcs and min thickness on insulation for his walls is 60mm (like I have used).
He's only looking at doing this because he's got all this extra material lying around otherwise wouldn't bother.
Now obviously from the installation instructions this particular insulation slab type is used in stud walls/between roof rafters/in cavities on new build so requires mechanical support of some kind-however making a studded frame drastically raises the U value above the 0.3 required by BC. Am I OK to achieve a similar composite slab to my own K18 in the following way?:
1. 2x1 vertical battens fixed to wall to create a 1" air gap (and the extra 0.6 on the compsite slab R value).
2. Put the insulation board up
3. 12.5mm plasterboard on top then 100mm drywall screws through the whole lot into the battens.
4. 3mm plaster skim
Sound OK?
If an additional vap barrier is required where in the composite should it go? Would adding this affect the purported 0.6R gain of the foil face on the insulation board against the air gap layer?
(Or should I just tell him to try and sell the leftovers and buy K18 if he's that desperate to insulate like I did?)
Thanks for advice
Dave
