Cab over wood repair water damage rott

What I did on mine was I ripped out the
thin ply and then I accessed the damage. I found that
the floor/sleeper bottom was thin ply bonded to Styrofoam in mine.

I also found that the over the cab part had aluminum
framing on the sides. I went down the sides and I pop-ribbed
3x3x1/8 aluminum angle the entire length of the floor
on the wall side to the framework.

Then want across the front and back the same way.
Once boxed in with 3x3 aluminum I reinforced the good wood
supports with aluminum angle and replaced/then reinforced
the bad ones.

So now I have an aluminum boxed in sleeper with aluminum
supports. I replaced the foam insulation and used 7/16"
exterior sheeting for the floor/bed bottom and painted both sides.

On top of that I placed dense carpet padding, then the sleeper cushions.

The aluminum and padding came form Home Depot / Loews.
Bought an unfinished bunk bed ladder from Amazon and refinished
that to match the wood.

Holds my 215 lbs without a problem.