Rot in tongue and groove garden building roof

[prologica]

Hi,
I’ve got a 4m x4m garden building with a tongue and groove type planked pitched roof overlaid with felt shingles.
I’ve got a small area of rot near the ridge (affecting 1 or 2 planks). At the eaves where they overhang the walls quite a bit in a ‘log cabin’ type style, I can feel rot under the shingles.

Looking at timber prices, if the whole roof needed replacing it’s about £1k plus labour. I was wondering, whether it might be possible to saw off the rotten ends of the planks and scarf in sections of new planks somehow?

Any advice appreciated.
Thanks

 

[prologica]

ps the rot under the eaves may well effect quite a lot of the overhang on one pitch.

 

[conny]

Any pictures? It makes things easier than trying to mentally picture what you can see.