I am starting my bus build. We have a 40' Bluebird. My question or rather idea is this. We want a patio on the roof. We don't know what all else. My thought is, put a tubing frame down both side of the bus that are equal height to the dome of the roof. This will be installed before redoing the roof. I plan to sandblast and finish the roof with silicone roofing. The roofing would go over the tubing on the racks. Later, anything you would want on the roof would be attached to the racks. They would run the full length of the bus. That would keep me from having to attach through the roof every time I want to add something up above, solar panels, storage, kayak racks, and so on. The racks would be welded on before the roofing product goes on.