Spiral and Curved Staircases
Thursday, December 3rd, 2009Curved Staircases
A curved staircase is one that extends from one level to another without any turns or winders. A winder is a step that is narrower on one side than the other, used for changing the direction of the stairs without landings. A Two Curved Run Stair is a curved staircase consisting of two curved flights (sets of stairs leading to a landing) without turns but with one landing.
A True Radius Curve Stair follows the arc of a circle, while a combination of curved and straight stairs can also be built. These are quite distinctive and useful for places where space is an issue. They can cost more than a true radius curve, and the pitch change where the curved and straight sections join will need very careful planning to create a graceful transition.
Curved staircases can be supported or free-standing. Supported staircases have weight-bearing walls beneath them, usually enclosed to create a closet or basement stairwell. An inside radius free-standing staircase will have only the inside radius of the stair as free-standing without the outside radius supported, while a completely free-standing staircase does not have any intermediate supports. The staircase has to be carefully designed to bear its own weight without the stability of a support wall on either side.
Spiral Staircases
A spiral staircaseis one that is made up of a series of winders that follow the arc of a circle, that is a 360° turn. Curved stairs may also follow the arc of a circle, but do not complete the run. They often have multiple rotations, and twist upwards rather than diagonally. Consequently, spiral stairs are also known as helix staircases, corkscrew stairs, cockle stairs (named after the winding patterns on the cockle shell), and caracole stairs (named after coiled shape of a snail’s shell).
Spiral staircases are used for many purposes, including as a feature in larger foyers, transitions up to balconies and decks, accenting the openness of lofts, fire escapes and more.