Thanks Lucy for lots of useful info there. Glad to hear someone sing the praises of woodfibre. I insulated a dormer roof using 50mm Steicoflex woodfibre insulation between the rafters, with good results. First I fitted 50mm timber battens to the sides of the rafters to ensure an airgap to the tiles, then I pushed the insulation against the battens. It's fairly easy to cut with a breadknife, although you do end up covered in fibres. It fricton fits quite well, but I secured it using the big plastic washer things that are used to fit cavity batt insulation in a wall cavity. I snipped each one in half & ran a long screw through them, the insulation and into the batten. A few years on, the householder has had no problems and says the house is far warmer than with the poorly-fitted polystyrene that was there before. I think a competent DIY-er could do a good job. I was doing this work not long after the Grenfell disaster, so fire resistance was very much on my mind. Sceptical of quoted flame resistances, I did a bit of my own testing by placing various samples on the floor and blasting them with a blowtorch. Rockwool and fibreglass were fine & non-combustible, the woodfibre held up well although scorching and smoking slightly. The plastic-based samples I tried - polystyrene, expanding foam, foiled bubble-wrap, and layered foil & fabric were alarming. All caught instantly and burned brightly with lots of smoke until completely consumed. 'Fire rated' expanding foam melted almost instantly but didn't continue burning. As a result, I think I would still be happy to use foam-backed plasterboard as IWI, but only with careful detailing to ensure the foam remained in a closed-off gap, and I'd be reluctant to put any significant amounts of plastic-based insulation inside the building, except maybe some little bits in low-risk areas like layered foils around window reveals, fire-rated foam in gaps round external door & window frames, pipe entries, etc. Prior to this, I had insulated my own home with 50mm foam-backed plasterboard IWI, with good results and no problems. A once damp, cold and expensive to heat mid-terrace is now warm, dry and the bills have halved. I think some of the advice out there makes the perfect the enemy of the good. A friend was recently told he needed at least 150mm insulation in his solid-walled home, which is not viable even for his large house when you consider width of staircases etc. Similarly with some of the advice about damp. Before insulating, I think the dewpoint was more or less at the plaster render / brick interface, meaning that great chunks were coming away. and black mould was everywhere. Since stripping the render and dotting & dabbing IWI board on 10 years ago, I've had no problems despite being loudly warned "the house needs to breathe!!"
On the old Chapel walls you kuldip timer frame inside with small gap and insulate 50 to 100 mm with vapour barrier beforplasterbard. Uses bit more space but works well.
Not sure if you explained use of Tyvec roofing felt on your nouse Not sure if upyou indicated the costs and the heating ,underfloor water or electrical. Heat pump ? Secondary windows are effective if originals have to be used
Thanks Lucy for lots of useful info there. Glad to hear someone sing the praises of woodfibre. I insulated a dormer roof using 50mm Steicoflex woodfibre insulation between the rafters, with good results. First I fitted 50mm timber battens to the sides of the rafters to ensure an airgap to the tiles, then I pushed the insulation against the battens. It's fairly easy to cut with a breadknife, although you do end up covered in fibres. It fricton fits quite well, but I secured it using the big plastic washer things that are used to fit cavity batt insulation in a wall cavity. I snipped each one in half & ran a long screw through them, the insulation and into the batten. A few years on, the householder has had no problems and says the house is far warmer than with the poorly-fitted polystyrene that was there before. I think a competent DIY-er could do a good job.
I was doing this work not long after the Grenfell disaster, so fire resistance was very much on my mind. Sceptical of quoted flame resistances, I did a bit of my own testing by placing various samples on the floor and blasting them with a blowtorch. Rockwool and fibreglass were fine & non-combustible, the woodfibre held up well although scorching and smoking slightly. The plastic-based samples I tried - polystyrene, expanding foam, foiled bubble-wrap, and layered foil & fabric were alarming. All caught instantly and burned brightly with lots of smoke until completely consumed. 'Fire rated' expanding foam melted almost instantly but didn't continue burning. As a result, I think I would still be happy to use foam-backed plasterboard as IWI, but only with careful detailing to ensure the foam remained in a closed-off gap, and I'd be reluctant to put any significant amounts of plastic-based insulation inside the building, except maybe some little bits in low-risk areas like layered foils around window reveals, fire-rated foam in gaps round external door & window frames, pipe entries, etc.
Prior to this, I had insulated my own home with 50mm foam-backed plasterboard IWI, with good results and no problems. A once damp, cold and expensive to heat mid-terrace is now warm, dry and the bills have halved. I think some of the advice out there makes the perfect the enemy of the good. A friend was recently told he needed at least 150mm insulation in his solid-walled home, which is not viable even for his large house when you consider width of staircases etc. Similarly with some of the advice about damp. Before insulating, I think the dewpoint was more or less at the plaster render / brick interface, meaning that great chunks were coming away. and black mould was everywhere. Since stripping the render and dotting & dabbing IWI board on 10 years ago, I've had no problems despite being loudly warned "the house needs to breathe!!"
On the old Chapel walls you kuldip timer frame inside with small gap and insulate 50 to 100 mm with vapour barrier beforplasterbard. Uses bit more space but works well.
Not sure if you explained use of Tyvec roofing felt on your nouse Not sure if upyou indicated the costs and the heating ,underfloor water or electrical. Heat pump ? Secondary windows are effective if originals have to be used