Typical flat roof construction..

Hello everyone..
I was referred to Jensen Trailers and they said they build One Piece flat roofs which actually fold over the side walls.. Meaning the material is larger than the trailer, and then folded over the edge..
My only reference regarding construction techniques was my old featherlite who used a rounded extruded roof corner on top of the side wall and then a "one piece" roof which I always considered false advertising.. Because its not one piece and it leaked because it relied on sealant.
How do most trailer manufactures using flat one piece roofs construct them? Do they rely on the aluminum corner trim piece and caulk to seal it? Or do they also fold the roof material over the side walls like Jensen Trailers?
Thanks
I was referred to Jensen Trailers and they said they build One Piece flat roofs which actually fold over the side walls.. Meaning the material is larger than the trailer, and then folded over the edge..
My only reference regarding construction techniques was my old featherlite who used a rounded extruded roof corner on top of the side wall and then a "one piece" roof which I always considered false advertising.. Because its not one piece and it leaked because it relied on sealant.
How do most trailer manufactures using flat one piece roofs construct them? Do they rely on the aluminum corner trim piece and caulk to seal it? Or do they also fold the roof material over the side walls like Jensen Trailers?
Thanks