Hi,
Currently have a part-boarded loft in a 1950s semi with between 25 and 100mm of old glass fibre between the joists. Under the boarded area (22 sqm) there is 25-50mm insulation, 50mm airgap then chipboard panels. The unboarded area (19 sqm) has between 50 and 100mm.
I'm thinking it's about time to upgrade this insulation - would I be likely to notice a significant benefit since there is already some (poor) insulation there already?
The plan is to ensure all of the unboarded area has 100mm between the joists, then overlay either 170mm earthwool or 200mm space blanket - I guess there wouldn't be a lot of extra insulation benefit from the extra 30mm of the space blanket, but presumably it's a lot less dusty (never used earthwool though - is that as bad as GF, or would it be ok once down as long as not disturbed?). The space blanket would also be about £50 dearer than using the 170mm earthwool.
For the boarded area I was going to lift it and fully insulate with 100mm blanket between the joists, then put something like space board over the rafters, then relay the floor panels. Going by the R-value of the boards I'd need two layers of 52.5mm Space Board to get to the recommended insulation levels. Again, this board is expensive - would 2 layers show a significant benefit over 1? Is there a cheaper form of this type of insulation than Space Board, or perhaps something else I could use? I don't think I'm interested in cross-battening - seems like a lot of extra weight if I used 6x2s to get another layer of 150mm in.
Whilst looking at this, it struck me that there might be some value in insulating underneath the ground floor. It's a suspended wood floor with a 2-3 foot, well-ventilated void underneath. Currently has normal floorboards overlaid with 3mm foil/polystyrene underlay and 8mm laminate over most of the ground floor. Bathroom and kitchen are boards, 18mm ply then tiled. What sort of benefit would there be to, e.g., putting in a 100mm layer of the GF insulation (since it's so cheap at Homebase atm) and holding in with netting? Would I be likely to notice the benefits, in warmth perception or heating costs? I'm willing to spend a weekend or two on my back under the floor if I wouldn't be wasting my time.
(edited to add - since I may be under the floor anyway, should I add some lagging to the 8mm microbore heating pipes? Main supply pipes for water are lagged with the wraparound felt but they are the only ones that appear lagged to me...)
Any advice much appreciated.
Currently have a part-boarded loft in a 1950s semi with between 25 and 100mm of old glass fibre between the joists. Under the boarded area (22 sqm) there is 25-50mm insulation, 50mm airgap then chipboard panels. The unboarded area (19 sqm) has between 50 and 100mm.
I'm thinking it's about time to upgrade this insulation - would I be likely to notice a significant benefit since there is already some (poor) insulation there already?
The plan is to ensure all of the unboarded area has 100mm between the joists, then overlay either 170mm earthwool or 200mm space blanket - I guess there wouldn't be a lot of extra insulation benefit from the extra 30mm of the space blanket, but presumably it's a lot less dusty (never used earthwool though - is that as bad as GF, or would it be ok once down as long as not disturbed?). The space blanket would also be about £50 dearer than using the 170mm earthwool.
For the boarded area I was going to lift it and fully insulate with 100mm blanket between the joists, then put something like space board over the rafters, then relay the floor panels. Going by the R-value of the boards I'd need two layers of 52.5mm Space Board to get to the recommended insulation levels. Again, this board is expensive - would 2 layers show a significant benefit over 1? Is there a cheaper form of this type of insulation than Space Board, or perhaps something else I could use? I don't think I'm interested in cross-battening - seems like a lot of extra weight if I used 6x2s to get another layer of 150mm in.
Whilst looking at this, it struck me that there might be some value in insulating underneath the ground floor. It's a suspended wood floor with a 2-3 foot, well-ventilated void underneath. Currently has normal floorboards overlaid with 3mm foil/polystyrene underlay and 8mm laminate over most of the ground floor. Bathroom and kitchen are boards, 18mm ply then tiled. What sort of benefit would there be to, e.g., putting in a 100mm layer of the GF insulation (since it's so cheap at Homebase atm) and holding in with netting? Would I be likely to notice the benefits, in warmth perception or heating costs? I'm willing to spend a weekend or two on my back under the floor if I wouldn't be wasting my time.
(edited to add - since I may be under the floor anyway, should I add some lagging to the 8mm microbore heating pipes? Main supply pipes for water are lagged with the wraparound felt but they are the only ones that appear lagged to me...)
Any advice much appreciated.
