Both wall and roof panel construction is 16 ga. steel outer skin and welded internal framing members on 24" (600mm) centers. The inner skin is 22 ga. perforated steel (approximately 49% open area). Doors are left hand hinge or right hand hinge swing with magnetic gasket seals and neoprene seals. Custom sizes and styles are available, consult the factory for details. Windows are double glazed.