Hello all, I am in the process of renovating a house in the southern region of the US. The house was built in 1949 and we are about done replacing all the wiring to modern standards. No rooms had insulation, the age of the roof is unknown. We pulled the walls out of one of the bedrooms and came across several pieces of wood with rot and inner walls with rot. The person who pulled the walls also identified a leak where this wood is. Neither my wife nor I are experienced with this and are stressed this will be a major repair to take on as we are dealing with a re-wire.
I have someone who is helping with some other projects on the house. He said he could take care of the wood and fix the leak for a few hundred and it would not be an issue. He also stated he could put in a corner beam that is needed there anyways.
However I have another buddy who said it would be a massive undertaking and be quite expensive. The imgur album is below, I only have the three photos since I am not near the house currently. The rest of the wood on the truss and surrounding area is fine, the only damaged areas are in the photos. Any help would be appreciated, thank you!