Wet rot is probably the most common sort of rot that we see.  In its basic form on windows it simply needs filler or new timber splicing in and redecoration.  In its most severe form it can cause the floor joists to rot or roof joists (find photo).  (Man disappearing through the floor.) We had a trainee surveyor where the floor gave way in a pub as the wood was so rotten, it was in the top rooms and landlord hadn’t been in there for years!