6.6.6Structural design

Staircases shall be properly supported and transmit loads to the supporting structure without undue movement, deflection or deformation.

Staircases should be designed and comply with building regulations and Table 1.

Table 1: Standards for stair construction

Type of staircaseRelevant standard
Timber staircases
(straight flights, 1⁄4 or 1⁄2 landings)
BS 585: Part 1 or 2.

The method of fixing flights to the surrounding structure should be specified.
Reinforced concrete staircasesBS EN 1992-1-1 and Chapter 3.1 ‘Concrete and its reinforcement’

Should be designed by an engineer in accordance with Technical Requirement R5.
Steel staircasesBS EN 1993-1-1.
Proprietary staircasesTechnical Requirement R3.

Timber stud walls may require additional noggings to provide appropriate fixing locations, and block walls should be sufficiently robust to support the required loads and to receive appropriate fixings. It should be noted that stairs generally are unable to be secured to metal stud walls.

Differential movement

When considering differential movement in relation to setting out, levels and finishes, allowances should be made for:

  • casting tolerances
  • deflection under load
  • foundation settlement
  • creep and shrinkage
  • storey height.