Can I use joist hangers for stair stringers?

Can Joist Hangers Be Used for Stair Stringers?

While joist hangers are designed for supporting floor joists, their use for stair stringers is generally discouraged and often prohibited by building codes. Stair stringers experience different load patterns and forces than floor joists, and joist hangers may not provide the necessary strength and stability for this application.

The Difference in Load Bearing

• Joist Hangers and Floor Joists: Joist hangers are designed to primarily support vertical loads from floor joists, which transfer weight evenly across their span.
• Stair Stringers: Stair stringers experience a combination of vertical and lateral loads as people ascend and descend the stairs. These loads can create significant stress on the connection between the stringer and the supporting structure.

Building Codes and Safety Concerns

• Stringer Support Requirements: Building codes often require specific methods for supporting stair stringers, typically involving direct attachment to a ledger board, rim joist, or other substantial framing members.
• Joist Hanger Limitations: Joist hangers may not be listed or approved for use with stair stringers, and their use could compromise the structural integrity of the staircase.
• Safety Risks: Using unapproved or inadequate support methods for stair stringers can lead to structural failure, creating a serious safety hazard.

Alternatives to Joist Hangers for Stair Stringers

• Ledger Board: Attaching the stringer to a ledger board that is securely fastened to the rim joist or wall framing is a common and code-compliant method.
• Carriage Bolts: Carriage bolts can be used to connect the stringer directly to the rim joist or other suitable framing members.
• Notched Stringers: Notching the stringer to rest on the rim joist or ledger board can provide additional support and stability.

When Joist Hangers Might Be Considered

• Non-load-bearing Stringers: In some cases, joist hangers might be used for non-load-bearing stringers, such as those supporting a small landing or decorative element. However, it’s crucial to consult with a structural engineer or building official to ensure the application is safe and code-compliant.
• Temporary or Light-duty Staircases: Joist hangers might be suitable for temporary or light-duty staircases, such as those used during construction or for access to attics or crawl spaces. However, even in these situations, it’s important to prioritize safety and ensure the staircase is adequately supported.

Conclusion

While it may be tempting to use readily available joist hangers for stair stringers, it’s essential to prioritize safety and adhere to building code requirements. Opting for approved and structurally sound methods for supporting stair stringers is crucial to ensure the safety and longevity of your staircase.