Building Regulations Stairs Requirements Explained in Plain English

Building Regulations Stairs: How the Rules Apply in a UK Home

In most domestic homes, Building Regulations stairs requirements fall under Approved Document Part K. These rules are designed to prevent falls, ensure the staircase is comfortable to use and guarantee that anyone using the stairs can do so safely. Although every staircase is different, the core principles remain the same: correct proportions, safe guarding, adequate headroom, and stable, uniform steps.

When you install a new staircase, alter an existing set of stairs, or undertake works that materially affect how people move between floors, your local Building Control team will check these rules carefully. While some minor repairs fall outside formal inspections, anything that changes the geometry or structural safety of the stairs will require building regulations approval. For larger domestic projects, you may submit a Building Notice or full plans application.

Key Part K Stair Requirements (Domestic Properties Only)

Part K sets out the core safety rules for staircases in a home. Although some flexibility exists for refurbishments in tight spaces, the following rules will apply to most homeowners building or upgrading stairs.

1. Stair Width (Advisory but Important)

There is no legal minimum width for a domestic staircase in England, but Building Control expects a functional width. Most new homes use 800–900mm, and this is considered a safe minimum for everyday use.

• Very narrow stairs (below 700mm) are discouraged.
• Winder stairs should retain adequate turning width.
• Loft stair widths often mirror these advisory figures.

2. Consistent Rise & Going

Uniformity is vital. The rise and going must be consistent throughout the entire flight.

3. Maximum Rise & Minimum Going

Part K sets clear limits so stairs are neither too steep nor too shallow:

• Maximum rise: 220mm
• Minimum going: 220mm
• Maximum pitch: 42°

Stair Dimensions: Rise, Going & Pitch Explained

Rise is the vertical height between treads, while going is the horizontal distance from nose to nose. Together, they determine how steep your staircase feels. Part K expects a balanced approach — enough rise to move efficiently between floors without making the stairs unstable or uncomfortably steep.

To comply with the 42° pitch rule, most compliant domestic staircases use:

• Rise: 180–200mm
• Going: 220–250mm

Minimum Headroom Requirements

Headroom is one of the most common stumbling blocks for homeowners, particularly in older houses where beams and sloping roofs compete for space. Part K requires:

• 2.0m minimum headroom measured vertically from the pitch line
• Permitted reduction in loft rooms over the lower section of a winder (only with agreement from Building Control)

Where headroom is tight, a new stair layout or repositioned opening is often the only compliant solution. Our team regularly helps homeowners reconfigure their plans so they meet headroom requirements without major structural changes.

Handrails, Balustrades & Guarding

Handrails must be easy to grip and positioned consistently.

• Handrail height: 900–1000mm above pitch line
• Located on at least one side of stairs with two or more risers
• Balustrade gaps: No opening greater than 100mm
• Landings must have guarding to prevent falls

Part M: Accessibility Requirements in Domestic Homes

Although most existing houses only need to follow Part K, Part M (accessibility and usability) applies to new-builds and some material change-of-use projects. In domestic stair design, Part M influences several practical details even if full M4(1) compliance isn’t required.

Key considerations from Part M include:

• Handrails should extend the length of the flight for ease of use.
• Consistent handrail height helps people with reduced mobility.
• Stair widths should be practical to navigate, generally 850mm+.

Homeowners extending or converting should be aware that Building Control may refer to “reasonable provision” under Part M to ensure stair usability for all future occupants.

Step-by-Step: How to Check Your Stairs Against Building Regulations

Common Pitfalls That Cause Building Control Delays

• Inconsistent rises — often caused by miscalculated floor-to-floor height.
• Insufficient landing length, especially where doors open onto stairs.
• Balustrades with decorative openings above 100mm.
• Handrails installed too low or too high.
• Incorrectly positioned stair openings in lofts leading to failed headroom checks.

If your stairs are part of a larger project like a loft conversion or house extension, the staircase also influences fire safety routes and Part B compliance. Coordinating these early helps avoid build-time rework.

FAQs: Building Regulations Stairs

Key Facts Snapshot

Next Steps & Useful Guides

Here are helpful next reads based on your project:

• Building Regulations: Complete Homeowner’s Guide
• Building Control: What It Is and How It Works
• Building Notice vs Full Plans
• Plans for Building Regulations
• Loft Conversions (UK) – Full Guide
• House Extensions – UK Guide
• Building Control Inspections
• Fire Safety: Part B in Domestic Projects

External References

• Planning Portal – National Guidance
• GOV.UK – Planning Permission Rules