Winnebago wants to sell new ones at $4500 each, so they don't really cater to inquiries about repairs.
Some posts say that the top is made from PVC (Polyvinylchloride) plastic. This is not true. The outer shell is made from ASA (Acrylonitrile-Styrene-Acrylate) plastic and the inner headliner is made from ABS (Acrylonitrile-Butadiene-Styrene) plastic. Both are weldable
I just repaired some very large (3/4 of the way across the top) and some very small (1/2 inch) cracks, suing some simple, inexpensive tools and a little patience.
I posted details of the repair process :
http://tahosa.us/Eurovan/Eurovan/index.html
