The Spiral Stairs & Spiral staircase specialists...

Staircase Building Regulations...what you need to know!

As we are often asked whether certain staircases comply with building regulations, we thought it may be useful to inform our clients as to the restrictions and requirements surrounding many aspects of home improvements as well as the building regulations pertinent to staircases. Although we sell stairs of diameter 100cm on this site, that does not necessarily mean they comply with all regulations.

Staircase category i.e. Min-max rise per tread Min clear widths per tread Min centre goings per tread

A Small private stair 170-220mm 600mm 145mm

B Main stair of a house 170-220mm 800mm 190mm

C Semi Public 170-220mm 800mm 230mm

We always suggest you contact your local council prior to any work. However click below for part K of the building regulations section BS5395 charting all the relevant information with regard to the building regulation requirements for staircases.

Domestic spiral staircases come under 2 aspects of the Building regulations depending upon their usage

Primary stair - For a main stair serving 2 or more habitable rooms you require a 800mm clear width (900mm in Scotland), max rise of 220mm and a centre going of 190mm. Generally 1800mm diameter staircases and above are used in this instance.

Secondary staircase - For a spiral serving 1 habitable room it should have a 600mm clear width, max rise of 220mm and centre going of more than 145mm.

String / Stringer - the structure that supports the treads and risers which can be in wood or steel
Tread - the part of the stair that you walk on
Going - The individual going is the horizontal measurement from face of riser to face of riser
Riser - the vertical portion between each tread on the stair. There are closed or open risers
Rise - The individual rise is the vertical measurement from top of tread to top of tread
Nosing - the front part of the tread that overhangs the riser, they actually overlap each other slightly.

Staircase Terminology...some helpful explanations


On all staircases, spiral or straight there are some regulations that are consistent. There should be no gaps anywhere on the staircase whether between spindles or treads larger than 100mm / 4 inches. In the spiral staircase above you will see that the vertical spindles meet with this and because the treads are open, we have added a horizontal bar known as a riser bar to close this gap also to less than 100mm.