I am looking to insulate under the roof to create a warm loft space; I have plans to insulation between the rafters and across these under the rafters, but can't work out whether I need to leave a gap between the roof membrane and the insulation or not.
Other parts of the house have already had the whole gap filled with (fibre) insulation, with no apparent problems.
My gut feeling is to leave the gap anyway, but this just means that the insulation across the rafters has to be thicker to compensate, with subsequent loss of headroom.
The house was built in the south of UK in the early 1970s.
Any thoughts or ways to identify the type of membrane ; I have not yet found any markings on it to identify it?
Other parts of the house have already had the whole gap filled with (fibre) insulation, with no apparent problems.
My gut feeling is to leave the gap anyway, but this just means that the insulation across the rafters has to be thicker to compensate, with subsequent loss of headroom.
The house was built in the south of UK in the early 1970s.
Any thoughts or ways to identify the type of membrane ; I have not yet found any markings on it to identify it?
