stairwells

Stairwells are vertical enclosures that house stair flights connecting floors in a building. They provide primary vertical circulation and are typically enclosed to separate occupants from other spaces, though some designs are open for daylight or architectural effects. Stairwells may be straight, L- or U-shaped with landings, or curved, spiral, or alternating-tread configurations. In large buildings, multiple stairwells may serve as independent egress routes.

The essential elements of a stairwell include treads and risers, landings at floor changes, stringers or supporting framing, and handrails along at least one side (often both). Guardrails or balustrades protect open sides, and there is usually a required headroom clearance above the treads. Materials vary by building type, with concrete or steel common in commercial work and wood or steel in residences; prefabricated metal stair assemblies are also used.

Code and safety provisions govern stairwells. Building codes specify minimum width and headroom, uniform rise and run, durable slip-resistant finishes, and lighting requirements. Fire-resistance ratings and fire doors are typical for enclosures intended as egress stairs, and emergency lighting and signage are often mandated. Separation from non-evacuation spaces and protective fireproofing are common in high-rise construction.

Stairs are not always accessible to occupants with mobility impairments; elevators or lifts provide alternative routes where required. Handrails must be continuous and graspable. Regular maintenance includes checking rail stability, treads for wear, lighting, and the integrity of enclosures.