STAIR | TYPES OF STAIRS | TYPES OF MATERIALS USED IN STAIRS CONSTRUCTION

 

In buildings, the stair is a term applied to a complete flight of steps between two floors.

 

TYPES OF STAIRS

Generally, stairs are of the following types

1.     Straight stairs

2.     Quarter-turn stairs

3.     Half turn stairs

4.     Three quarter turn stairs

5.     Circular stairs

6.     Spiral stairs

7.     Curved stairs

8.     Geometrical stairs

9.     Bifurcated stairs

 

Straight stairs

These are the stairs along which there is no change in direction on any flight between two successive floors. The straight stairs can be:

a.     Straight run with a single flight between floors

b.     Straight run with a series of flights without change in direction

c.      Parallel stairs

d.     Angle stairs

 

Scissors stairs

Straight stairs can have a change in direction at an intermediate landing. In the case of parallel stairs, the stairs require a complete reversal of direction. In the case of angle stairs, the successive flights are at an angle to each other. Scissor stairs are comprised of a pair of straight runs in opposite directions and are placed on opposite sides of a fire-resistive wall.

 

Quarter turn stairs

They are provided when the direction of flight is to be changed by 90°. The change in direction can be effected by either introducing a quarter space landing or by providing winders at the junctions.

 

Half turn stairs

These stairs change their directions through 180°. It can be either ‘dog-legged or ‘open newel type. In the case of dog-legged stairs, the flights are in opposite directions and no space is provided between the flights in the plan. On the other hand, in open newel stairs, there is a well or opening between the flights and it may be used to accommodate a lift. These stairs are used at places where sufficient space is available.

 

 

Three quarter turn stairs

This type of stairs change their directions through 270°. In other words, the direction is changed three times with its upper flat crossing the bottom one. In this type of construction, an open well is formed.

 

Circular stairs

These stairs, when viewed from above, appear to follow a circle with a single centre of curvature and large radius. These stairs are generally provided at the rear of a building to give access for servicing at various floors. All the steps radiate from a newel post in the form of winders. These stairs can be constructed in stone, cast iron or RCC.

 

Spiral stairs

These stairs are similar to circular stairs except that the radius of curvature is small and the stairs may be supported by a centre post. The overall diameter of such stairs may range from 1 to 2.5 m.

 

Curved stairs

These stairs, when viewed from above, appear to follow a curve with two or more centres of curvature, such as an ellipse.

 

Geometrical stairs

These stairs have no newel post and are of any geometrical shape. The change in direction in these stairs is achieved through winders. The stairs require more skill for its construction and are weaker than open newel stairs. In these stairs, the open well between the forward and the backward flights is curved.

 

Bifurcated stairs

These stairs are so arranged that there is a wide flight at the start which is subdivided into narrow flights at the mid-landing. The two narrow flights start from either side of the mid-landing. Generally, these stairs are more suitable for public buildings.

 

TYPES OF MATERIALS USED IN STAIRS CONSTRUCTION

The following materials are used in the construction of stairs:

 

Stone stairs

The stones employed in the construction of stairs are hard, durable, weather-resistant and fire resistant.

The stone steps can be either

a.     Cantilevered from the wall

b.     Built into the wall at both ends

 

Brick stairs

They are rarely used except as entrance steps. A brick stair may be built of solid masonry work. The surface of the stair may be given any suitable type of floor finish.

 

 

Wooden stairs

Wooden stairs are light in weight and are generally used for residential buildings. The greatest limitation of wooden stairs is that it catches fire easily, and in case of a fire, the occupants of upper floors will find no way of escape. If the good quality  timber of proper thickness is used, it resists fire to a great extent and the occupants will have enough time to escape.

 

RCC stairs

These stairs are commonly used in all types of constructions. They can resist wear and fire better than any other material and can be cast to the desired shape. The advantages of the RCC stair are as follows:

a.     It can resist fire in a better way.

b.     Movement over it produces less noise.

c.      It can be cast.

ALSO READ: REQUIREMENTS OF A GOOD STAIRCASE | HOMESLIBRO

ALSO READ: Staircase Components or Parts Details | Staircase Design 

 

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