As you can see, the wood in my bathroom ceiling is looking a little rough. I’ve poked at it with a screwdriver and thankfully it’s more solid than it looks. Additionally, the previous owners basically laid an entirely new roof deck on top of it, so it’s not all of the structure. I’ve walked around up there and it seems solid. 

 

Seems to me like the roof was leaking before they put the new one on. No leaks now, and everything is bone dry, the framing has been exposed for at least six months now. 

 

But before I put up new drywall, how can/should I treat the existing wood?