: Dear Terry, I have just recently pulled out my old shower cubicle in my 1st floor flat only to find that it has been leaking for years and that the joist beneath it is now very damp and will come away in my hand. The joist is the end one which runs parallel to the outside wall and it is about 2 metres long. Please could you advise me on how to replace it/repair it.
: Many thanks........Chris

Chris,
Sounds like a damaged rim-joist.
I do more plumbing than work with a hammer, but it does sound like you will need to pull the siding off to get to the bad wood and replace. I'm thinking you will need to brace underneath and replace sections from the foundation to the flooring. I've had bathrooms, where I have chainsawed out entire sections from the wall and replaced wood all the way back to the beam supports.

A little water left alone will do wonders to the structure of a home.