Staircases and Building Regulations: A Comprehensive Guide for Your Extension

Staircases are covered by Building Regulations which regulate various safety features. 

You can’t just go ahead and build any staircase without ensuring they’re up to spec for Building Regulation compliance. 

While this is relatively straightforward for the main staircase, it’s more complex for a staircase that leads to a third-floor or loft conversion. Fire protection regulations require homes to feature a protected escape route from each habitable room. 

Here are the need-to-know Building Regulations for staircases. 

Staircase width and height 

There’s no regulation for staircase width, but it’s wise to build them at standard width to make lifting furniture up and down easier. The industry standard is 750mm for residential homes, but condensing them down to around 600mm is common for compact loft conversion stairs. 

Most domestic properties are allowed 16 stairs, which is more than enough for even exceptionally tall homes. 

Max step height 

The height of a step is called the rise, whereas the distance between each rise is a run. 

Steps need equally sized run and rise. So, you can’t build one step at 180mm high and the other at 220mm high, which makes the stairs pretty unpredictable and risks accidents. 

• The rise should be 150mm to 220mm
• The run should be 223 to 320mm

Generally speaking, most stairs are built to the rule of 18, which involves runs and rises of 18 inches. The 18 rule is what most are used to and deviating from it is rarely worth the time and effort. You could call it the Goldilocks zone of staircase design. 

Head height regulations

Stairs require 2000mm headroom at a minimum. This applies to the entire staircase from the bottom to the top. Head heights are simple to calculate and rarely pose an issue. 

Handrail staircase regulations

One of the most important staircases build regulations is the handrail. Handrails are a legal requirement, and each side of the staircase must have one if the stairs are 1m or less wide. 

If the staircase is wider than 1m, the staircase needs both handrails. Handrails are placed between 900mm to 1000mm above the highest point of the steps. 

Spindles and posts shouldn’t have a gap of 100mm or lower to prevent children from getting their heads stuck. To test this, a sphere with a diameter of 100mm mustn’t fit between the rails. 

Maximum staircase pitch 

Staircases can’t be too steep, as this will make them dangerous and difficult to climb. As a result, regulations apply a max 42° incline. 

Stair pitch is the slope of your staircase and can be worked out by dividing the run of your steps by the rise.

Landing regulations 

The landing is the space that leads to the staircase on each floor, including the ground floor. 

The landing space also needs to comply with staircase regulations. For landings on the second storey and above: 

• The space between door openings and the staircase should be 400mm minimum. 
• The landing should not contain permanent obstructions. 
• The landing should be flat, except for at ground level. 
• Handrails need to protect the overhang between 900mm and 1000mm from the floor.