Cover weathered plywood w/T1-11?
I live in Phoenix, Az, where it gets super hot and revives very little rain. My garage was built by the previous homeowners out of 2x4s and plywood. The plywood is very weathered and getting weak in that if you kick it in some parts, you can kick a hole right through. Would it be safe/advisable to place T1-11 right over it? Or, does the old stuff have to come down? I'm concerned that moisture could form between the old plywood and new T1-11 and eventually have growth of mold or something between the two, even though it's so dry here. Any advice?