How are air leaks stopped around roll-up doors in a steel structure?

The best way to stop leaks around roll-up doors is to install heavy-duty weather stripping and “brush seals” along the top and sides of the door frame. A “bulb seal” or rubber gasket should also be used at the bottom where the door meets the concrete. These seals close the gaps that naturally exist in metal-to-metal contact, preventing expensive heated or cooled air from escaping.