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- 2 Jun 2004
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I live in 1930 chalet house, that has open first floor joists at either side of the house, open at the internal skin of the exterior cavity wall (blown filled).
This means that cold air can get in from the soffit (through some gaps in the wall for timbers), and flow pretty freely into the first floor joist cavity making the rooms very cold. Also it results in hot air from the ground floor not staying in the house and escaping by the open floor cavity.
I have drawn an indicative construction to show this area (as attached), the red is where i plan to put celolex (50mm gap to the roof). I also plan to put celotex on 45 degree angle from the floor to the rafters if you can make it out. This will be boarded out with a couple of adjustable vents to allow ventilation into the space, its eave storage to avoid mould.
So what is left is what do i plug the joist cavities with, and how much? they are 200mm joists, do i just fill 200mm of loft insulation from the internal skin for 400-500mm internally under the floorboard, or do i use celotex and try and get a much better air tight seal. Of course i don't want rot to occur.
Cheers
WN
This means that cold air can get in from the soffit (through some gaps in the wall for timbers), and flow pretty freely into the first floor joist cavity making the rooms very cold. Also it results in hot air from the ground floor not staying in the house and escaping by the open floor cavity.
I have drawn an indicative construction to show this area (as attached), the red is where i plan to put celolex (50mm gap to the roof). I also plan to put celotex on 45 degree angle from the floor to the rafters if you can make it out. This will be boarded out with a couple of adjustable vents to allow ventilation into the space, its eave storage to avoid mould.
So what is left is what do i plug the joist cavities with, and how much? they are 200mm joists, do i just fill 200mm of loft insulation from the internal skin for 400-500mm internally under the floorboard, or do i use celotex and try and get a much better air tight seal. Of course i don't want rot to occur.
Cheers
WN