material for roof deck

[H3Jim]

The coach came with 2" foam inserted between the roof struts, so I've left that in place and comvered with 3/8 plywood, and eventually some decorative ceiling covering such as masonite, foam and vinyl / upholstery fabric.  When walking othe roof if i step; between the supports, I can feel the roof give a little.  its a thin aluminum skin so I don't want to walk on it much.

On either side of the coach I have front to back lateral arm awings that are mounted on the edge of the roof, so I have a natural barrier, although its short.  When I do the roof deck I will use some sort of planking, aluminum or fiberglass and put some railings around it hopefully like Sean's - they are sweet.