What’s the Minimum Width of a Staircase?
When planning a staircase — whether for a new build, a renovation, or a replacement — getting the sizing right is essential. Understanding the regulations and practical restrictions from the outset helps you set realistic expectations and make the best use of your available space.
Below is a clear breakdown of everything you need to know about minimum staircase widths in the UK.
Why Staircase Sizing Matters
The width of a staircase, along with each of its components (such as treads, risers and handrails), directly affects safety, comfort and overall aesthetics. Many homeowners aim to include space-saving staircases or fit stairs into challenging layouts, so proper sizing becomes even more important.
You should also consider how the size impacts your budget, installation requirements, and long-term usability. Above all, your staircase must be safe for all members of the household, which means complying with UK Building Regulations throughout the design.
What Is the Minimum Width of Stairs?
If you’re planning a staircase in a narrow area, understanding the rules around minimum widths is crucial. Most guidance is outlined in Approved Document K of the UK Building Regulations.
For buildings other than dwellings:
The minimum clear stair width between walls or strings must be 1200mm (or 1000mm between handrails).
For residential properties:
Surprisingly, there is no strictly defined minimum stair width for typical domestic staircases.
However, where a stepped change in level is required on a steeply sloping entrance storey, a minimum of 900mm is recommended.
In practice, staircases should always be designed to be comfortable, safe, and practical. At Ovoms, our designers will guide you on the ideal width for your home, especially if you want to include features such as glass balustrades, floating treads, or integrated lighting.
What About Loft Conversion Staircases?
While there are no specific minimum-width rules for loft stairs, several other requirements must be considered:
Fire safety compliance (including escape routes)
Headroom and pitch limitations
Space-saving design options
Structural adjustments, such as cutting existing ceiling joists
Restrictions that often result in narrower staircases
Retractable or fold-down loft ladders are not suitable for habitable rooms. Working with a specialist ensures your loft staircase remains safe, compliant, and well-integrated with the rest of your home.
Get Expert Guidance from Ovoms
If you’re planning a new staircase or renovating an existing one, Ovoms is here to help. Our team specialises in premium floating, central spine, zigzag and closed-tread staircases — all engineered to meet UK Building Regulations while elevating the design of your home.
We provide full design, manufacturing, installation and support across London and the surrounding regions.
For expert advice on staircase sizing or any other design questions, contact us today for a free consultation.
