Should be fine with a roof rack (or without if you don't care about the paint)
When I buy sheet steel I use a station wagon because it's easier to plop it down on a roof rack and get it off later then it is to stick it in a truck or van.
When I buy sheet steel I use a station wagon because it's easier to plop it down on a roof rack and get it off later then it is to stick it in a truck or van.