RE: Cargo Trailer Ceiling Material
I used 3/4 inch foam board on my roof and then lined from the inside plastic panels from Lowes-they are white in color made of plastic in 4X8 sheets-same material as you would use in a not so fancy shower stall-cuts easily and screws with self tappers into the roof ribs-they have a 1 inch divider strip to join two panels at seam.