Do I Need a Breather Membrane Between Insulation and Roof Tiles if There is no Felt? Information, help, tips and advice on cavity walls, ceilings and lofts etc....

[Dan77]

Hello everyone
I am in the process of having the living space i my loft room regulated into a bedroom. Currently there is no insulation so I have stripped the plaster down to the roof tiles. As it’s an older house there is no felt.
I have had the council round who advices me to fit Kingspan/ Celotex between the rafters then foil/ multi quilt over the top.
He did not mention anything about using any breather membrane so I’m wondering is this necessary as there is no felt. He also advices me that I only needed to leave a 25ml air gap and not 50ml between insulation and tile, is this correct?
The horizontal battins that the tiles are attached to are 25ml thick anyway so with a further 25ml gap would make 50.
I am currently waiting to hear back from the council with these questions but I need to speed it up.
Any advice will be greatly appreciated.

[collectors]

You would have to take the tiles off & the batterns to fit breather membrane as its made to let water & condesqation run off on the outside, usualy into the gutter.

[Dan77]

Thanks for clearing that up. I won’t bother then as wouldn’t want water running into the house.