On the rare occasions that a mechanical engineer asks for advice on roof‐mounted ductwork during the design phase, the first piece of advice might be: don’t do it. Just don’t put the ductwork on the roof. Duct is relatively lightweight with a large face area, especially on main duct lines coming off rooftop equipment. It makes an excellent sail and ideally duct should never be mounted on the roof in wind‐prone regions.
