What are stair joists called?
Stair Joists: Are They the Same as Stringers?
Brief Summary
While the term “stair joist” is sometimes used casually, the structural members that support the treads and risers in a staircase are technically called stringers. They are crucial load-bearing elements that ensure the stability and safety of the staircase.
Expanded Answer
Stringers: The Backbone of the Staircase
- Function: Stringers are the inclined boards that run along the sides (or sometimes the center) of a staircase, providing the structural framework for attaching the treads and risers. They bear the weight of the stairs and its users, transferring the load to the floor or supporting structure.
- Types:
- Cut Stringers: These have notches cut into them to accommodate the treads and risers. They offer a classic look with exposed treads and risers.
- Closed Stringers: These have routed grooves to house the treads and risers, creating a more streamlined and modern appearance.
- Mono Stringer (or central stringer): A single, central stringer supports the staircase from underneath, allowing for a visually open and floating design.
Why the Confusion?
- Interchangeable Terms: In casual conversation or by some contractors, “stair joist” might be used to refer to stringers. However, this is technically inaccurate.
- Joists vs. Stringers: Joists are horizontal framing members used in floors and ceilings, while stringers are specifically designed for inclined staircases.
- Similar Function: Both joists and stringers provide structural support, leading to the occasional confusion in terminology.
Building Codes and Stringers
- Stringer Design & Dimensions: Building codes dictate specific requirements for stringer dimensions, material strength, and attachment methods to ensure safety and structural integrity. These requirements consider factors like the staircase’s span, anticipated loads, and the chosen material.
- Inspections: During construction or renovations, building inspectors will verify that the stringers comply with applicable codes. Failure to meet these standards can result in safety hazards and costly rework.
Stringer Material and Trends
- Wood: Traditionally, wood (often dimensional lumber or engineered wood products like LVL) has been the primary material for stringers due to its availability, workability, and aesthetic appeal.
- Metal: Steel or aluminum stringers are increasingly popular, especially in modern and contemporary designs. They offer high strength, durability, and design flexibility.
Conclusion
While the term “stair joist” is sometimes used informally, “stringer” is the accurate term for the structural members that support treads and risers. Understanding this distinction is important for clear communication and proper construction practices. Remember, stringers are critical load-bearing elements that must comply with building codes to ensure the safety and longevity of your staircase.