good question. I'm fixing my personal camper. however, it has not been all that hard. All I have done was to learn from other people from YouTube videos and hopefully this information will help you and add to the library of information about this subject on the Internet.
I have a 1996 Rockwood 2307 premier popup. my problem is similar to yours, the biggest being that the corners of the aprons of the roof were rotting behind the exterior paneling. water definitely got in and did damage. so much did the water do damage, that the corner posts that were attached to the aprons with small carriage bolts pulled out and the roof was hardly able to be raised up... all four corners!
on your camper roof aprons, do you see the little carriage bolts that are on each corner?
is the wood behind them rotten? Or is it solid as if it was brand new? I can see from your picture that's it looks like you have water damage..... is this damage isolated to one area? I could tell that there was water damage behind my outer paneling because the paneling started to ripple. in my case, both aprons had to be removed for inspection and possible duplication. and sure enough, I had to duplicate both aprons.
I only have one picture on my phone right now as the project continues, but i will include it on a post when at my computer to be able to show you what the panels are turning out like. they are about 12 foot 4 inches long and 10 inches tall. my first challenge was finding a solution to locating replacement outer paneling. I had posted a link above about paneling from another company that's very thin
, but I did not want to wait for product to be shipped to me hoping its the right stuff... you can tell that the existing panelling on your trailer is only about one millimeter thick. there is a company that makes 4 by 8 sheets of fiber reinforced plastic...FRP... If you live near Wisconsin, Menards carries it. However, if the color that you need is almond it will probably be special order. I did not want to wait. So I went to my local Lowes. yes they had this product in almond color. and the texture is very similar to my trailer. all I needed was one sheet for about 26 dollars plus gas. here's the issue..it is 3/32" thick, much thicker than the one millimeter paneling on my trailer and your trailer....Look at Lowes website.
the overall original thickness of my outer apron panel is 9/16ths". so I want to keep that measurement while duplicating the outer panels. so I did the math. 1/2" OSB plus one new 3/32 panel of FRP from Lowes leaves me with the final measurement of 1/32" oversized. anyone can live with that. the original OSB is thicker but in this case, the outer panel will be just as strong as the original when duplication is finished. so thinner OSB is just fine. why didn't the trailer company issues better would that be? My dad and I were fighting back and forth figuring out the answer. our best guess is this. When you pull a sheet of plywood off a shelf, unless it is furniture grade plywood with red oak veneer or birch veneer that's three quarters of an inch, it will not be flat. it will be twisted and curved.. I do not want that part of the aprons of my camper roof. pull a sheet of OSB off the pile and it will most likely be 95% flat. now my dad and I knew why OSB was probably used, besides being an expensive. it is flat. And straight. As long as it's kept dry, it should not fail, since they even use it roots and on floors in homes. so I bought a sheet of half inch.
I knew I had to work through another issue, because the plywood is only 8 feet long and I needed aprons that are over 12 feet long. that is another post.. if anyone needs that information I will be happy to spend some time and post it with some information I found of Internet.. and products that are used in my piano shop.. products that can be bought anywhere.
anyway, the company who makes all the different wood glues..Titebond? Menards and Lows Carry a product made by Titebond called FRP Adhesive. It is specifically designed to adhere to fiber reinforced plastic sheeting. I am just about to adhere my almond FRP to my 1/2" OSB with full confidence That the bond between the two will be successful based off of Titebonds reputation. I have complete confidence in them. the product comes in one gallon bucket and is a little over $20. I am NOT a fan of looking for the cheapest solution. If this company has made an adhesive just for these panels... someone on this planet is thinking and I will pay them for their time..
I will post a picture of the adhered panels and let you know if I'm happy with the adhesive bond. I plan on doing the job by Friday eve. if you're curious, look up the FRP ADHESIVE on Titebonds website. if you have rotted wood. and it's dirty. and the back of the paneling is dirty, you need to make a judgement call if adhesive will work or if your camper needs surgery.