Hi Smuzz, I'm about two weeks ahead of you I should be uploading some new pic's soon myself.
I found rot in the rear floor under a leaking tail light assem.
I see in your pic's some corrosion around the lower body strip, That must be moisture.
I assume your gutting it? then you can really check everything.
In looking through these forums over the past month it looks like 95% of the floor problems are from leaks, so after I replace the section in my rear floor I am putting a 6oz layer of fiberglass over the entire floor with epoxy resin. It will only add about 20lbs or 35 with two layers.
That I believe this will prevent any future floor rot and preserve the trailer for another 25 years. (unless the rot is somehow from underneath)
I'm also making a fiberglass bathroom floor pan with a floor drain.
It's not a big deal with fiberglass, I'm making a perimeter around the bath floor with some 1" wood, then lay the fiberglass on the floor and lap it up and over the 1" wood, you now have a water tight pan that will not let any water on the main floor when you get out of the shower or if the toilet has a problem. Any water that may accumulate will go down the drain thru the belly pan or banana skin.
I'll post pic's in about 10 days when it should be done.
'77 Sovereign Intl 31' CB
WBCCI R2 Rep VAC 11411 Metro NY VP