Stair Details

Stair details refer to the standard requirements governing each of the various components of a flight of stairs. Regulated by building codes, especially in conditions serving emergency public egress, stair details specify the height and depth of risers and treads, the widths of stairs for differing occupancy loads, the placement and dimensions of handrails and guardrails, and typical construction methods for fabricating a flight of stairs.

Common Questions

* Under Development *

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Stair Details

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Stair Details

Buildings
Stair Risers & Treads
Diagram illustrating the standard dimensions of stair risers, treads, and nosings
Responding to the movement of the human body, the sizes and relationships of stair risers and treads are regulated to make vertical motion safe and easy. Steep stairs make climbing more tiring and dangerous, while shallow stairs are awkward and inefficient for our human stride.
Responding to the movement of the human body, the sizes and relationships of stair risers and treads are regulated to make vertical motion safe and easy. Steep stairs make climbing more tiring and dangerous, while shallow stairs are awkward and inefficient for our human stride.
Stair Risers & Treads

*Under Development*

Riser Height: 4" | 100 mm min.; 7" | 180 mm max.
Tread Depth:
11" | 280 mm min.
Nosing Protrusion: 
1.5" | 38 mm max.
Nosing Radius: .5" | 13 mm max.

  • Riser and tread dimensions should be continuously uniform for safety; building codes limit variation to 3/8" | 10 mm
  • The underside of risers should be sloped or have a 60° angle minimum between nosings and the horizontal surface
  • Open risers are not allowed under ADA guidelines
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Stair Widths
Diagram comparing multiple measured widths of stairs with a single person for scale
Stair widths are based on the use and occupancy loads of adjacent spaces and must be serviced with handrails on one or both sides depending on the stair width. In general public spaces a minimum of 44” | 112 cm must be met. Handrails must be placed every 60” | 152 cm.
Collection of dimensioned stair widths with people ranging from 1 person to 3 person widths
Stair widths are based on the use and occupancy loads of adjacent spaces and must be serviced with handrails on one or both sides depending on the stair width. In general public spaces a minimum of 44” | 112 cm must be met. Handrails must be placed every 60” | 152 cm.
Collection of dimensioned stair widths with people ranging from 1 person to 3 person widths
Stair Widths

*Under Development*

1 Person (Private): 36” | 91 cm
1-2 People (Min. Public): 44” | 112 cm
2 People: 49” | 125 cm
2 People (Comfortable): 60” | 152 cm
3 People: 74” | 188 cm
Human Body Accommodation: 22” | 56 cm

Drawings include:
Stair Widths front elevations, front (people)

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