5. Light Gauge Metal Connectors and Corrosion

The term “light gauge metal connectors” is used in this Course to highlight the importance of corrosion protection for lighter gauge connectors such as the prefabricated connectors that are used to facilitate wood connections. However, metal connectors fabricated from thicker steel will also benefit from this guidance.

Light gauge metal connectors are commonly used in several locations throughout wood-framed buildings. Concrete and masonry structures may also use them. Although light gauge metal connectors are not unique to wood-framed buildings, this Course highlights aspects of using them in wood-framed buildings in areas where corrosion can occur.

Light gauge metal connectors are often used to create a load path by securing roof framing to the tops of load-bearing walls, connecting walls of upper floors to lower floors, and connecting walls to foundations. The selection of the type of metal connector to use for specific applications may be dictated by the building code or may be based on the relative ease a type of connector offers in making complex framing connections. Metal connectors such as wind anchors may be used instead of toe-nailed connections to increase the strength of connections of a roof truss to a top plate (see Figure 2). In some cases, such as when attaching floor joists to floor band joists, metal connectors ca n both improve the connection and also reduce labor costs (see Figure 3). In some portions of a building’s load path, light gauge metal connectors can make the connection several times stronger than a connection that is readily achievable by nails alone.

Despite the benefit of being stronger than nails alone, light gauge metal connectors have drawbacks in coastal environments. Metal connectors that are prone to corrosion can lead to load path failures and structural damage during natural hazard events. The following are examples of important metal connectors potentially subject to corrosion:

• Hurricane straps and wind anchors used to connect roofs to walls (see Figure 2)
• Truss plates that connect the members of pre-manufactured roof and floor framing systems
• Joist hangers used on floor joists (see Figure 3), beams, and rafters
• Other metal connectors such as those used to improve lateral load resistance