Joist hangers are designed to provide support underneath the joist, rafter or beam to provide a strong a connection. Simpson Strong-Tie offers a diverse line of hangers to handle almost any application with top flange, concealed flange and field-skewable and slopeable options. HUC heavy-duty face-mount joist hangers are designed for schools and other structures requiring additional strength, longevity and safety factors. Install wood joists to wood, masonry and concrete. Seat width: 3-1/8 In. Nominal joist size: Double 2x10. Made from 14 Ga. steel. ZMAX galvanization offers extra corrosion resistance for exterior and treated-wood applications.