I have a very old FWC Granby where some of the plywood on the shell needs to be replaced. I am looking for any guidance or recommendations on how plywood should be replaced on sidewalls, floor, etc.
I just did all of this....Well, I'm actually turning a contained International Scout FWC unit into a slide in model for my Scout Terra pickup... Nice thing for you is that all the old pieces are still in place so you can simply measure them out and cut new ones for a direct replacement.
Replacing the wood is fairly straightforward and will be easiest if you have camper jacks. I would remove the floor and bottom sides of the tub from the top and then build a new floor and bottom sides. I used 3/4" ACX plywood on the sides and 3/4" treated plywood for the floor.
I would then remove and replace the horizontal side panels.
This is the trickiest part because you lose a lot of your structure when you remove the horizontal plywood from the sides. You might want to find a way to add some rigidity. I simply secured a 2x4 across the camper to add some extra strength, but my camper didn't come with the aluminum frame in the very front so it may not have been as sturdy as yours (I added a panel there with wood).
I would replace the overhang bed area last. Stay away from the particle board!
I used butt joints with waterproof gorilla glue. We tacked them into place with brads and then finished with screws, but you can just use screws. I drilled pilot holes... It is very strong.
Good luck - be sure to post photos and keep us posted on the progress with your new camper!
