How to replace damaged sarking board and roof felt (if needed at all?)

[DIYNotIan]

Hi

I've got a repair to do where an old wood stove flue used to go through the roof, but has since been taken down. Water had been leaking through and caused some rot to the rafter, which I will "sister" with some new timber.

What I don't know is whether it would be a good idea to repair/replace the sarking board, and the felt on top of it? If so, is it possible to do what needs doing from inside the room? Or is the only option to strip back slates and repair from above. Would prefer to do it from inside if at all possible.

Any opinions and suggestions on how best to approach this would be most appreciated.

Many thanks

 

[Tigercubrider]

An idea?
slip some kind of dpm material into the edge of the hole between the slates and existing sarking, so it pokes half out?
you may be able to entirely cover the hole if you were fortunate.

then cut a disc of osb/ ply to fit the hole and fix it with a couple of bits of timber?