Staircases: geometry standards and types in building carpentry trade

Rise, run, and the step rule — how to build a safe and comfortable staircase

Introduction

A staircase must balance several considerations at once: it must be safe to walk on, pleasant to use in everyday life and often must fit in a limited space. This makes staircase building one of the most mathematically demanding tasks in carpentry where millimeter precision and a sense of geometry go hand in hand.

Staircase basic concepts

01Rise — the vertical height from the top of one step to the next
02Base — the tread's horizontal surface, which you step on
03Rise ratio — the ratio between rise and run, which determines how steep the staircase appears
04String — the angled bearing side structure, the steps are fastened in
05Landing – a horizontal rest point where the staircase changes direction or provides a pause

The stride rule

A well-known rule of thumb for a comfortable walking pattern is that 2 × rise + run should be around 610–630 mm. The rule is based on the natural stride length an average person walks with and is used to establish the right ratio between rise and run when a staircase is to be designed.

Requirements in the building regulations (BR18)

Beyond the convenient, a staircase must also be safe. The Building Regulations' access requirements set specific targets for stairs in common access routes, which, among other things, must ensure that elderly people, children and people with reduced mobility can move safely.

Requirement	Value (common access routes)
Maximum rise	0,18 m
Minimum ground (straight run, quarter and half-turn stairs)	0,28 m (0,25 m i boliger)
Minimum clear width	1,0 m
Minimum clear height (above step edge and in walking line)	2,10 m

Staircase types

01Straight-run stairs — one straight run with no direction change, simple and space-consuming
02Quarter-turn stair — turns 90° via a landing or wedge-shaped steps
03Half-turn staircase — turns 180°, often via one or more landings
04Spiral staircase — winds around a central column, space-saving but less comfortable
05Room stairs — designed so steps and stringers are included as a visible part of the room's architecture

Execution and quality

A good staircase is known by details: steps that are indented or routed in the string rather than just nailed or screwed distributes the load better and gives a staircase that does not creak and holds for many years. The material choice — typically oak beech or pine — is made based on both strength wear resistance and the desired appearance and the staircase is always checked for level plumb and correct measurements before it is finally fixed.

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Requirement

Value (common access routes)

Maximum rise

0,18 m

Minimum ground (straight run, quarter and half-turn stairs)

0,28 m (0,25 m i boliger)

Minimum clear width

1,0 m

Minimum clear height (above step edge and in walking line)

2,10 m