The Function of Screws in Cold-Formed Steel Framing

Screws serve an essential function in cold-formed steel (CFS) framing, facilitating the connection of components, attachment of sheathing, and providing a quick, dependable assembly method. These fasteners are utilized in both shop and on-site construction, with specific screws designed for tasks such as joining steel members with gusset plates or securing structural panels to the framework. The durability and stability of a CFS structure hinge on selecting and installing screws with the proper length, strength, and protective coating for their application. 

Key Functions of Screws in CFS Framing

Connecting Structural Members: Self-drilling screws are commonly used for bonding CFS components, including fastening gusset plates that link beams to columns. They are effective in creating shear-resistant connections and can also offer moment resistance.

Securing Sheathing: Screws serve as the primary fastening method for attaching sheathing materials such as plywood or oriented strand board (OSB) to CFS studs and joists.

Assembly and Fabrication: From assembling components like walls and trusses to constructing the final structure, screws are indispensable. They are particularly beneficial for on-site adjustments due to their flexibility.

Load Transfer: Properly designed screws facilitate the transfer of loads between components, contributing significantly to the structural stability of the building.

Accommodating Various Connections: In addition to joining structural members, screws are employed for attaching a broad range of elements, including drywall, to the steel structure.

The Importance of Correct Screw Selection and Installation

Penetration Depth: According to the American Iron and Steel Institute (AISI) S200 standard, screws must penetrate steel with at least three fully exposed threads to ensure a secure connection.

Corrosion Resistance: The appropriate screw coating, such as galvanization, should be selected based on environmental conditions to guard against premature deterioration.

Material Compatibility: Screws must match the steel's thickness, strength requirements, and expected load demands.

Expert Installation: For structural connections, screw types and specifications must align with a qualified designer's recommendations. Adhering to proper installation guidelines—using the correct number and type of fasteners—ensures performance reliability and minimizes risks of structural failure.