Angle
Determine the slope of the staircase.
The angle should be between 20 and 50°. Its ideal value is 30°.
Balancing
A balanced staircase is a staircase whose steps turn progressively at the angles.
Mainly used in Europe, balancing improves the comfort, safety and aesthetics of a staircase.
Balancing also increases the contact surface with the interior string.
Blondel's law
G + 2H = 590 to 650mm (23.2 to 25.6")
Formula invented by the French architect François Blondel (1618-1686) checking the coherence between the step height and the going.
The ideal value is 630mm (24.8").
Flight
Series of steps between 2 landings.
Going
Horizontal distance between two step nosings.
The going should be between 230 and 330mm (9 and 13").
Its ideal value is 280mm (11").
Half-turn staircase
A half-turn staircase or double quarter-turn staircase is a staircase with 2 90° angles.
Headroom
Distance between the ceiling and the walkline at the stairwell.
The headroom should be greater than 1900mm (75") and the ideal value is greater than or equal to 2100mm (83").
Height
Vertical distance between the lower floor and the upper floor.
Japanese staircase
An alternating tread staircase or space saver stairs is a staircase with L-shaped steps, enabling the user to go up or down alternating steps. This saves space and provides a steeper slope, while maintaining a comfortable step depth.
Landing
Horizontal surface wider than the current steps.
It allows to mark a rest or to change the direction of the staircase.
Landing step
Step in the extension of the upper floor.
It allows an overlap on the last step.
It also facilitates the connection of the string and the handrail with the upper floor.
Overlap
Part of the step covered by the top step.
The overlap improves the comfort of the staircase.
Quarter-turn staircase
A quarter-turn staircase is a staircase with a 90° angle.
Riser
Vertical part connecting 2 consecutive steps.
Spiral staircase
A spiral staircase is a staircase whose steps radiate around a central axis.
Stair width
Useful width of the staircase.
The stair width must be greater than 700mm (28") and its ideal value is greater than or equal to 800mm (32").
Stairwell
Opening in the upper floor allowing the passage of the staircase.
Step
Horizontal surface on which the foot is placed.
Step height
Vertical distance between two step nosings.
The step height should be between 150 and 200mm (6 and 8").
Its ideal value is 175mm (7").
Step nosing
Protruding part of a step.
Straight staircase
A straight staircase is a staircase without any change of direction.
String
Element that allows to hold the steps of staircase.
Total run
Horizontal distance between the nose of the first step and the step nosing of the upper floor.
Walkline
Fictitious line symbolizing the user's passage.
It is used to determine the going for turning staircases.
If the stair width is less than or equal to 1m (40") then the walkline is located in the middle.
If the stair width is greater than 1m (40") then the walkline is located 500mm (20") from the inner handrail.