Staircase

A staircase is the element that lets people walk between two different levels by way of steps. Each step has a horizontal tread and a vertical riser; a run of steps forms a flight, and the flat platforms between flights are landings. Stairs come in many forms: straight, L-shaped, U-shaped or dog-leg, winder and spiral.

Designing a comfortable stair

Comfort depends on the relationship between riser height and tread depth. A widely used rule of thumb says that two risers plus one tread should equal an average stride, roughly 60 to 64 cm. Within a flight, every step must be identical; even one odd step is enough to make people trip. Flight width, continuous handrails, headroom and the spacing of landings are set by building regulations according to the building type, and fire escape stairs, travel distances and protected enclosures are regulated separately.

The stair as a sculptural element

A staircase is often the most eye-catching thing in a space. Cantilevered treads, glass balustrades or a single folded concrete ribbon can define the character of an entrance hall. In a render, the light and shadow lines along the stair nosings are among the best cues for depth, so adding a small bevel to tread edges improves the image noticeably.