Originally Posted by sdAir
Thanks Bob! I will check out your post. The floor in the rear feels fine ( no soft spots or dark areas) Is there any other place other than removing the shower pan and toilet I can check back there to see if there is rot?
We did replace the last 4' of floor the first winter we had the trailer. If you look at the blog link, its all documented there. Unless you have a trailer that came from a desert climate or was stored inside all its life, its a fairly sure bet you will have some rot, especially in the back. I didnt care for the layout of the rear bath, so when I gutted it, I put in everything new except the toilet and even that got put on a pedestal to get it about 4 inches higher.
To make sure there are no issues there, you could pull the banana wraps in back and pull away the insulation and see what the bottom of the plywood looks like, especially at the edge where it connects to the c channel and the shell. The design of these trailers has a big inherent flaw in that they rely on the plywood to keep the whole structure stiff. Its like a box with all sides taped shut, hard to deform, but if you open up one or more sides, then the rest of the box can move.
The frames in these 70's vintage trailers are undersized and especially with the longer rigs, the weight of the frame itself will pull it away from the floor and the shell. For peace of mind, you should get a good look at the floor either from the top or the bottom. If you don't want to replace the bath, then go with the process that has less deconstruction which is from the bottom. And if it is rotten, its all gotta come out anyway. But its still not shell off.