[Neweller]

Hi David and a big welcome to the Newell Talk Forum. Regarding your question on the wall plywood, it should be 5/8" thick marine grade with seven layers preferably. I have done several repairs and complete wall replacements on these Newells. The seven layer is not cheap and can set you back anywhere from $60-120 a sheet depending on your access and availability to the product. Not any lumber yard or especially a big box store carries any such animal. If you tell me where you are located I could possibly suggest a vender. Or contact a marine repair and ask them, hopefully they will give you a good lead..

It is very common to find rot on some older Newell's and even some newer ones depending on how well the windows, drip rails and such have been sealed etc...If these areas are not maintained on a normal basis depending on weather conditions your coach is exposed too, you can develop leaks and may not even be noticeable and next thing you know there is some rot like this.

Ken