Structural terminology (stairs): In building construction, the beams that support the treads and risers along the sides of a staircase are called ________.

Introduction / Context:
Staircases are assemblies of structural and architectural components. Correct terminology helps in detailing, load estimation, and site communication. The long inclined members that carry the steps (treads and risers) need a precise name in structural drawings.

Given Data / Assumptions:

• A conventional straight flight stair in a framed building.
• Steps (treads and risers) are supported along their edges by inclined members.
• We are to identify the correct term used for these supporting members.

Concept / Approach:

In stair construction, the inclined side members that directly support the steps are known as stringers (also called strings). Other terms such as headers, trimmers, or spandrel beams have different, specific roles in floor and frame construction, not the direct support of stair treads/risers along the slope.

Step-by-Step Solution:

Verification / Alternative check:

Typical structural details label these members as “stringers/string courses,” with thickness and connection details to floor beams or landings. Architectural references align with the same naming convention.

Why Other Options Are Wrong:

• Headers: floor framing members running perpendicular to joists near openings, not stair supports.
• Trimmers: joists or beams that frame openings (e.g., around stair wells), not the inclined stair members.
• Spandrel beams: edge beams at slab perimeters or façade lines, not for stair step support.
• Girders: primary beams; not the specific inclined stair members.

Common Pitfalls:

• Confusing trimmer joists at the stair opening with the inclined step-supports.
• Using generic terms like “beam” instead of the precise term “stringer.”

Final Answer:

Stringers.