Dog-leg (stairs)

Dog-leg is a term used to describe a configuration of stairs between two floors of a building, often a domestic building, in which a flight of stairs ascends to a half-landing before turning 180 degrees and continuing upwards.^[1] The flights do not have to be equal, and frequently are not.

Structurally the flights of a dog-leg stair are usually supported by the half-landing, which spans the adjoining flank walls.

From the design point of view the main advantages of a dog-leg stair are:

To allow an arrangement that occupies a shorter, though wider, floor area than a straight flight, and so is more compact. Even though the landings consume total floor space, there is no large single dimension
The upper floor is not directly visible from the bottom of the stairs, thereby providing more privacy
An object or person falling from the upper half of the stairs is likely to stop at the landing; this is safer than letting it fall all the way to the bottom.

References

^ Hartwell, Clare; Pevsner, Nikolaus (2009) [1969]. Lancashire: North. New Haven and London: Yale University Press. p. 741. ISBN 0300126670.