Angle irons/lintels are pieces of steel placed above window and door openings to support the masonry above the opening. Prior to 2008, nearly all of this steel was not galvanized. The galvanized coating gives the steel great protection from moisture damage, creating longevity. If your home or building was built prior to 2008, you might see rust forming along the steel or horizontal or stairstep cracks in the mortar joint where the steel sits on the masonry. If you see these symptoms, it might be that the angle irons/lintels need to be replaced.