Stairs

Stairs are a connected series of steps used to move between levels. A stair run consists of treads (horizontal surfaces) and risers (vertical spaces). They are supported by stringers, and may be enclosed by walls or open on one side. Stairs may be interior or exterior.

Common configurations include straight stairs, L-shaped stairs (two straight runs on a common landing), U-shaped stairs (two back-to-back runs with a landing), spiral stairs (gradual circular ascent), and winder stairs (tapered steps that turn without a landing).

Dimensions and ergonomics: a typical residential stair uses risers around 7 inches tall and treads around 10 inches deep; angle commonly 30 to 37 degrees. The number of steps is determined by total rise divided by the riser height; landings are required for multi-flight stairs. Building codes specify minimum headroom and accessible handrail requirements: for instance, headroom at least 6 ft 8 in in many jurisdictions; handrails at one or both sides.

Materials and construction: stairs may be framed in wood, concrete, steel, or a combination; treads may be finished with wood, carpet, tile, or metal; exterior stairs require weather-resistant materials and drainage considerations. Interior stairs may be finished to match interior design.

Safety and maintenance: non-slip surfaces, adequate lighting, and continuous handrails are recommended; regular inspections help identify loose treads, worn finishes, or protruding nails.