Approved Document K Explained: Essential Compliance for Building Regulations

What is Building Regulations Part K?

Approved Document K is part of the Building Regulations in England. It focuses on preventing injury from falling, collisions and impacts. This includes rules for stairs, ramps, balconies, windows, glass doors, and more.

It is used by architects, builders, and developers to design and build safer spaces. Whether you’re building from scratch, converting a commercial building into flats, or fitting out an office, Part K helps reduce the risk of everyday accidents.

The document is publicly available and sets out clear guidance, with measurements, technical drawings and legal thresholds. You can read the full Approved Document K here.

What does Part K cover?

Part K is divided into six key areas, each one focused on a specific type of safety hazard.

Stairs, ladders and ramps (K1)
This section outlines the minimum design standards for stairs and ramps. It includes details on dimensions such as tread depth and riser height, the steepest pitch allowed, and where handrails should be placed. The aim is to reduce tripping, slipping and falling accidents.

Barriers to prevent falls (K2)
When a floor edge, landing, roof terrace, or balcony is above a certain height, barriers must be included to stop people from falling. K2 sets the height, strength and positioning of these guardrails and balustrades. These rules apply in residential homes as well as in schools, offices and public spaces.

Vehicle barriers and loading bays (K3)
In commercial and industrial buildings, Part K applies to spaces where vehicles move close to pedestrians. It includes barrier requirements for car parks, service yards and loading docks.

Impact with glazing (K4)
Large glass panels, especially those at lower levels or indoors, present a risk of serious injury. This section of Part K requires the use of toughened or laminated safety glass in specific zones to reduce this danger. It also includes visibility markings for large areas of clear glazing.

Extra rules for glazing in non-domestic buildings (K5)
In schools, hospitals, offices and other non-residential settings, extra safety glazing requirements apply. This includes higher impact resistance standards for doors, screens and partitions.

Safety with powered doors and gates (K6)
Automatic doors and gates must have systems in place to prevent injury. This includes sensors, safety edges and fail-safe systems that reduce the risk of trapping or striking people.

If you’re working on a non-domestic building, K5 and K6 become particularly important. These rules help keep public environments safer for children, elderly users, and those with limited mobility.

More background on the scope and purpose of Part K can be found in this briefing paper from the House of Commons Library, which also explores how it fits into wider UK housing standards.

When does Part K apply?

Part K applies to a wide range of projects and property types. Here are the most common situations where it is required:

• New homes, commercial buildings, and public buildings
• Loft conversions where a new staircase is added
• Extensions involving raised floors, balconies or glazed areas
• Renovations involving window replacements or large glazed doors
• Fit-outs of offices, shops, or hospitality spaces
• Developments changing the use of a building, such as a commercial-to-residential conversion

In each case, the project must comply with Part K to get Building Regulations sign-off, which is separate from planning permission. You can learn more about the relationship between planning approval and building regulations in our guide to Planning Permission in London.

Stair regulations under Part K

Stairs are one of the most used features in any building, and also one of the most hazardous if poorly designed.

Here’s what Part K requires for safe staircases:

Maximum pitch of 42 degrees
This keeps staircases comfortable and safe to climb without feeling too steep.

Consistent rise and going
Each step should be the same height (rise) and depth (going) to avoid missteps and trips.

Minimum headroom of 2 metres
Clear headspace prevents people from bumping their heads on ceilings, beams or floors above.

Handrails on stairs
Stairs under 1 metre wide need at least one handrail. Over 1 metre, handrails are needed on both sides.

Landings for rest and safety
Long staircases should be broken up with landings to provide safe rest points.

These rules also apply to spiral staircases and alternating tread stairs, although slightly different standards are set. You can find practical examples in this Part K article on c-link.com.

Window safety and guarding explained

Falls from windows are still a risk in UK homes, particularly for children. Part K steps in with clear requirements.

If a window has a sill height lower than 800mm, and it is on a floor above ground level, safety measures must be put in place. These can include:

• Guarding fixed in front of the window, like a barrier or balustrade
• Restricted opening mechanisms that limit how far the window can open
• Toughened or laminated glass to reduce injury risk if the glass breaks

In blocks of flats, student accommodation or care homes, these rules are especially important. Window safety should also be considered alongside Part M accessibility rules, which often affect window heights and access.

Glazing and toughened glass requirements

Glazing is one of the most overlooked safety areas in building design. Part K spells out when and where safety glass must be used.

Here are some of the key rules:

• Safety glass is mandatory in doors and side panels if the glazing is below 1500mm from the floor
• Low-level windows under 800mm from the floor also require toughened or laminated glass
• Visibility markings should be added to large panes of clear glass in busy areas to avoid collisions

Toughened glass breaks into small blunt fragments rather than dangerous shards. Laminated glass holds together on impact, preventing a person from falling through.

This has crossover with sustainable building design. As outlined in our guide to improving EPC ratings, well-chosen glazing can also boost thermal performance.

How Part K links with fire safety in Part B

While Part K focuses on falls, impacts and injury, Part B focuses on fire safety, including evacuation and escape routes. The two documents often work together.

For example:

• Staircases must allow for safe use in everyday situations (Part K) and be protected as fire escape routes (Part B)
• Glass partitions might need to meet impact safety rules under Part K and also be fire-rated under Part B
• Doors might need powered closing mechanisms (Part K) but also allow for smoke control (Part B)

We’ve written a dedicated guide to Part B of the Building Regulations, which explains how to handle fire compliance on residential and commercial builds.

Why clients trust WindsorPatania for building regulations

At WindsorPatania, we design with regulations in mind from day one. This helps you avoid delays, redesign costs, or rejections from building control.

Clients working with us benefit from:

• Architectural and interior design aligned with Approved Documents
• Consultation services that anticipate safety and access requirements
• Project management that keeps builds compliant from start to finish
• In-depth experience across housing, commercial, and specialist projects

We’ve supported everything from Class MA conversions to EPC upgrades and garden room installations. You can explore more examples across our Planning and Building Regulations hub.

Summary: Making Part K part of your build

Part K is not just a set of technical standards. It’s about creating spaces where people can move around safely without risk of serious injury. From stairs and balconies to glass doors and gates, these rules matter for every type of property.

Getting it right means fewer surprises during inspections, a smoother building process, and better peace of mind for end users.

Book a discovery call

Whether you’re designing your next project or mid-way through a renovation, WindsorPatania can help you meet every building regulation with confidence.

Book your discovery call with our team today to speak with our architects and consultants.