I am renovating the guest toilet after it was smoke-damaged and have discovered that there is rot in the load-bearing beam that is part of the outer wall. There is a rafter resting approximately in the middle of the slightly more than a meter that crosses the toilet.
Is it worth making an intervention to replace the beams? I had a cleaner here because of the smoke, and she sprayed on a bactericidal agent.
The rot seems to have gone about 25mm into the two bottom studs which are 135mm, and the top one seems to have fared better.
There was a leak around the chimney that the previous owner seems to have lived with for a while, but I fixed it about 2 years ago.