Dog legged staircase is the simplest form of staircases in which a flight of stairs goes up to a half step before turning 180 degrees and continuing upwards and used in public and residential buildings.
Because of its appearance in sectional elevation, it is called Dog Legged Staircase and is a very common and popular type of staircase and consists of two flights that run in opposite directions which are separated by a landing in the middle space.
The dog legged staircase is used when the available space is equal to twice the width of the stairs and this staircase lies in its compact layout and better circulation from a design point of view.
In dog legged staircase, stairs are arranged with two adjacent flights running parallel with a mid landing and dog legged staircase is generally provided resulting in economical utilization of available space where space is less.
Landing is provided corresponding to the level at which the direction of the flight changes in this type of staircase.
Details of Dog Legged Staircase:
To several floors of the building, the stairs provide access and with landings at appropriate intervals, the staircase consists of a series of steps.
Each step consists of a tread and a riser and the stairs are made up of individual steps. The riser is the vertical part like up and down between each step of the stair and the floor is the flat part you step on.
The landing is provided according to the level at which the direction of the flight changes in this type of staircase and is the most economical staircase.
The Requirement for Good Stairs:
For an easy, fast, and safe ascent or descent, any well-planned stairs must meet the following criteria such as;
Length of Flight
Pitch of Stairs
It must be located in order to achieve adequate lighting and ventilation with easy access from all rooms.
Length of Flight:
A flight should have no more than 16 risers and no less than three risers.
Pitch of Stairs:
From 15 degrees to 55 degrees, the stairs are inclined and between 25 degrees to 40 degrees is the recommended angle. By using landings long stride should be flattened.
The width of the landing must not be less than the width of the flight of stairs in any case.
The rise of each stage on flights and landings between floors must be the same and any variations can ruin the pace and to ensure the comfortable access, the climb is provided.
Example of Dog Legged Staircase Design:
Designing a dog legged staircase for a residential building where floor to floor height is 3.3 m and the space provided is 2.5 m x 4.5 m.
Basically, for residential buildings, we adopt Rise, and the tread of each step is 150 mm and 225 mm.
Dimensions of Stair hall
I = 2.5 m x 4.5 m
Height of Floor = 3.3 m
Total No. of flights = 2
Height of one flight = 3.3/2 = 1.65 m.
Rise = 150mm &
Tread = 225 mm
So, No. of risers = 1650/150 =11.
Number of treads = 11-1 = 10.
Stair adopting width = 1.2 m
The length required for 10 treads = 10 x 0.0225 = 2.25 m.
Width of landing = (4.5-2.25)/2 = 1.125 m.
Advantages of Dog Legged Staircase:
There are the following advantages of dog legged staircase as given below;
Efficient Use of Space: This type of staircase allows for a more compact stair arrangement and covers much less area than the straight staircase.
Privacy: If you want to separate one floor from another for any reason these stairs are great and to users, these stairs offer ample privacy as the top floor cannot be seen and vice versa.
Disadvantages of Dog Legged Staircase:
There are the following disadvantages of this staircase such as;
Difficult to Built: This is not easy to build these types of stairs.