A stair is a set of steps leading from one floor to the other. It is provided to afford the means of ascent and descent between various floors of the building. The room or enclosure of the building, in which the stair is located, is known as staircase. The opening or space occupied by the stair is known as a stairway. In a domestic building the stairs should be centrally located to provide easy access to all rooms. In public buildings, stairs should be located near the entrance. Stairs may be constructed by timber, bricks, stone, steel or reinforced cement concrete. Staircases provide access and communication between floors in multi-storey buildings, and are a path by which fire can spread from one floor to another. Staircase, therefore, must be enclosed by fire resisting walls, floors, ceiling and doors. It is desirable that the linings to the walls and the ceilings are non- combustible and of low flame spread. Another important aspect in the design of stairs is the strength aspect. It must be designed to carry certain loads, which are similar to those used for the design of floor.
STAIRS AND ITS TYPES
Single flight straight stairs
Double flight straight stairs
Quarter turn newel
Half turn newel
Open wall stairs
Dog legged stairs
STAIRS OF DIFFERENT MATERIALS
TIMBER STAIRS: these stairs are light in weight and easy to construct, but they have very poor fire resistance. They are used only for small rise residential buildings. Sometimes, fire resisting hard wood of proper thickness may be used.
STONE STAIRS: these are widely used at places where ashlar stone is readily available. Stone stairs are quite strong and rigid, though they are very heavy. Stone used for construction of stairs should be hard, strong and resistant to wear. The simplest form of stone stairs is those supported on both the ends, though an open well stair case can also be built.
BRICK STAIRS: these are not very common, except at the entrance. However, brick stairs of single straight flight are often made in village houses. The stairs consist of either solid wall, or also, arched openings may be left for obtaining storage space.
METAL STAIRS: stairs of mild steel or cast iron are used only as emergency stairs. They are not common in residential and public buildings, though they are strong and fire resistant. These are commonly used in factories, godowns, workshops, etc.
R.C.C: these are the stairs widely used for residential, public and industrial buildings. They are strong, hard wearing and fire resisting. These are usually cast- in – situ and a wide variety of finishes can be used on these.
DOG LEGGED STAIRS
Dog legged stairs are the stairs in which the user climbs up to a flight turns at one eighty degree n then climb stairs in opposite direction