Rotten Roof Timbers

Hi all, first post so go easy on me!

I have a 200 plus year old cottage. My plan was to replace the fascias and guttering over the next couple of weeks. However taking off the existing fascias has uncovered some rotten timbers, wet. The ends of a couple of teh roof trusses are rotten, I understand i can repair these with plywood fillets etc. But worse is the wooden plate that the ends of the trusses are sitting on. This has very bad rot in several places and needs to be replaced. Is this a) easy to do, b) possibly causing further as yet undiscovered issues with the rest of the roof?

Dave.

Wet rot can be cut out and repaired,where necessary.(Dry rot is something entirely different)..Access to repair by the sounds of this may be involved.You really need to attatch photo's...for anyone to advise,as the type of roof covering needs to be assessed especially being an old cottage,and the ceilings may determine the process involved.

Is it your intention to remove the roof covering?