There are several types of stairs used in construction based on their shape and arrangement.
A stair are structure having a series of steps and riser, the main purpose for ascent and descent between the floors or landings.
The enclosed room in stair is situated is called the staircase and the opening space occupied by the stair is called a stairway.
Stair may be made from timber, stone, bricks, steel, plain cement concrete, or reinforced cement concrete consists of treads, risers, stringers, balusters, and other linked elements.
Classifcation of stairs based on geometry:
This straight stair runs directly between two floors include a single flight or more than one flight with a landing which is used for smaller homes.
The turning stair has an opening or well hole between the front and back flights that is determined according to geometric principles.
The change of directions is radiated from the center of curvature between the flights by winders.
These types of stairs can be circular, spiral, helical, or elliptical, these stairs require good care and skill in their construction, they further may be classified as:
A) Quarter turn stair:
When the flight direction is to be changed by 90°, quarter-turn stairs are provided to change its direction to the left or right.
This can be achieved by starting a quarter space landing or providing a winder, they are classified as follows:
Newel quarter turn stair:
These stairs have new posts at the beginning and end of each flight.
Quarter-turns can be either space landings or winders.
Geometrical quarter turns stair:
In these stairs, stinger and railing is continuous with no new positions on the landing.
B) Half Fold Stair:
These stairs change their direction through 180°, these may classified as follows:
Dog-legged stair consists of two straight flights with an abrupt turn between them, the flights run in the opposite direction with no space between them.
These types of stairs may be classified as follows:
- With half-space landing and
- With quarter space landing and winders.
Dog-legged stairs with quarter space landing and winders are most common.
Open new half-turn stair:
The open new half-turn stairway has a space or well between the outer wires, the major difference between the open newel half-turn ladder and the dog leg steer.
Geometric half-fold Stairs:
In this geometric half-fold stair, stringer and band rails are continuous without new posts without interference, they can exist with or without a half-position landing.
C) Three quarter turn stairs:
These three quarter turn stair is used when the size of the staircase room is restricted and when the vertical distance between the two floorings is massive sufficient.
These types of stairs have changed their direction three times along their upper flight.
D) Bifurcated stair:
This bifurcated stair is very common in public buildings in which it appears as a prominent feature.
In these stairs, the flights are organized in a wide flight on the wall which is subdivided into narrow flights at mid-landing.
Two narrow flights begin in the entrance on both aspects of the centre landing.
E) Circular stair:
Circular stair when viewed from top, appear to follow a circle with a center of curvature and a large radius.
These types of stairs are usually constructed in R.C.C. Cast iron or stone.
F) Spiral stair:
Spiral stairs are similar to circular stairs besides that the radius of curvature is small and the tray of the staircase is supported by a middle part.
These stairs could be constructed from cast iron, mild steel or concrete.
Also read: Stair Landing, Parts of stairs & Principles of Planning
Different types of stairs based on materials:
They are often employed in framed structures or R.C.C. Structure.
These stairs has better resistance to wear and fire than any other material, while it can be molded to any desired shape and size.
The steps and landing can be provided by various finishing materials such as marble, quota, granite, ceramic tiles, terrazzo etc.
These stairs are strong, rigid, durable and pleasing, while they can easily kept clean and easily withstand even non-slippery.
These types of stairs are suitable for greater width and longer duration, generally constructed in cast-in-situ and prefabricated structures.
4.Timber or wooded stair:
Timber stair is commonly used for residential buildings due to its lightness made either built-in or shops fabricated & fire resistance.
The wood used for construction should be free from fungal decay and insect attack, it should be treated well before use.
Stair Stringer provides support for the steps, the stringers are bent wooden members 3 to 5 cm thick and 25 to 40 cm deep.
Mild steel and cast iron stairs are used in factories, warehouses, workshops, etc.
These types of stairs consist of steel channels acting as stringers, the thread consists of a steel checker plate or concrete slab.
They are supported by small angles on the stringers, concrete can be used for threads filled with steel troughs or steel grating.
Spiral staircases are other form of metal stairs that are commonly used in factories, warehouses, workshops, etc.
They are not common in residential and public buildings as they are strong and rough resistant because they are not good-looking and make a lot of noise when used by users.
6.Precast concrete stairs:
Precast concrete units are nowadays available for constructing concrete stairs of various shapes.
Also read: Types of Doors, Types of Buildings & Types of Windows