These metallic supports transfer loads from the joist to the support and come in three basic types. Face-mounting joist hangers are fabricated from 12- and 18-gauge galvanized steel and are pre-punched to receive 10d and16d nails, depending on the manufacturer's recommendations. When heavier loads are called for, top-mounting joist hangers may be specified. They are fabricated from galvanized or hot-rolled steel, which is coated with corrosion-resisting primer. Integral straps tie the hanger to the tops of the support. Skewed joist hangers are designed to carry joists that don't run perpendicular to the support.