Approved Document K explained

What is Approved Document K?

Approved Document K is the statutory guidance for Part K of the Building Regulations 2010 in England, covering protection from falling, collision and impact: stairs, ramps, guarding, vehicle barriers, glazing, and in non-domestic buildings, windows and doors. The current version is the 2013 edition, which took effect on 6 April 2013 and absorbed the former Approved Document N on glazing.

Unlike Parts B and L, Part K has been stable for over a decade, so the figures in this guide have not moved. The 2013 edition on GOV.UK is still current in October 2026. It replaced the 1998 edition and Approved Document N, and moved some guidance previously in Approved Document M. Some printed and PDF copies still mention the 1998 edition in their transitional text; that only concerns the pre-2013 transition and does not mean the 1998 figures still apply.

Part K overlaps with Part M. Approved Document K deals with stairs and ramps for safety; Approved Document M deals with them for accessibility. Where external stepped access forms part of a principal entrance or the access route from the site boundary, both apply.

The figures are stable. The risk is copying them from an old project without checking which stair category or building type applies.

What requirements K1 to K6 cover

Part K sets six requirements in Schedule 1 to the Building Regulations 2010. K1 to K4 apply to dwellings and other buildings; K5 and K6 do not apply to dwellings.

Requirement K4 says glazing people are likely to contact must, if broken on impact, "break in a way which is unlikely to cause injury", or resist impact without breaking, or be shielded or protected from impact.

What are the stair rise and going limits?

Table 1.1 sets rise and going ranges for three stair categories. Any rise within the range can be paired with any going within the range, provided twice the rise plus the going falls between 550mm and 700mm.

Other key stair rules

Headroom

At least 2m over flights and landings (para 1.11, Diagram 1.3). For dwelling loft conversions where 2m cannot be achieved, 1.9m at the centre of the stair falling to 1.8m at the side (para 1.13, Diagram 1.4).

Open risers

Treads overlap by at least 16mm, and a 100mm sphere should not pass through the gap.

Risers per flight

In buildings other than dwellings and common areas of flats: up to 16 for utility stairs and 12 for general access stairs (exceptionally 16 in small premises). More than 36 risers in consecutive flights need at least one change of direction.

Landings

At the top and bottom of every flight, at least as wide and long as the smallest width of the flight.

Tapered treads

Consecutive tapered treads use the same going, no less than the straight treads in the same stair.

Spiral and helical

Design to BS 5395-2.

Handrails

900mm to 1000mm above the pitch line or floor. Stairs 1000mm or wider need a handrail on both sides.

What guarding heights does Approved Document K require?

Diagram 3.1 sets minimum guarding heights by building type and location. The working pattern is 900mm on stair flights and 1100mm at landings, floor edges and balconies, with 800mm at opening windows and in front of fixed seating.

When is guarding needed on a stair?

In dwellings, guarding is needed at the sides of flights and landings where there is a drop of more than 600mm. In buildings other than dwellings and in common access areas of buildings containing flats, it is needed where there are two or more risers. Elsewhere in those buildings, pedestrian guarding should prevent people falling more than the height of two risers, or 380mm where not part of a stair.

Where children may be present

In buildings that may be used by children under five, para 3.3 says a 100mm sphere should not pass through any opening in the guarding, and children should not be able to readily climb it, which means avoiding horizontal rails. Guarding must also resist the loads in BS EN 1991-1-1 with its UK National Annex and PD 6688-1-1 (para 3.2). Glazed guarding also falls under Section 5 on glazing.

Ramps, safety glazing and vehicle barriers

Table 2.1 limits ramp gradient by going: 1:20 for a 10m going, 1:15 for 5m and 1:12 for 2m. Safety glazing applies in "critical locations", defined by height above floor level and distance from doors.

Ramps used by people should be at least 1500mm clear between walls, upstands or kerbs (para 2.9), with landings at the foot and head at least 1200mm long and clear of door swings (para 2.13). Approved Document M Volume 2 uses the same gradient and going limits for access routes.

Manifestation applies to glass doors and glazed screens in buildings other than dwellings, including screens alongside corridors.

Vehicle barriers

Vehicle barriers under K3 should be at least 375mm high at the edge of a floor or roof and at least 610mm high at the edge of a ramp, as shown in Section 4, and designed for the loads in BS EN 1991-1-1.

Before a Part K figure goes into a specification

• ✓The stair category (private, utility or general access) is stated, and rise and going sit inside its range.
• ✓2R + G has been calculated, not assumed.
• ✓Guarding height matches the building type and location in Diagram 3.1, including balconies at 1100mm.
• ✓Glazing in critical zones has a safe-breakage, robustness or protection route stated.
• ✓The Approved Document M requirements for the same stair or ramp have been checked.

Because the Building Safety Regulator now has a duty to keep the Approved Documents under review, check GOV.UK before relying on a figure in a specification.

Where Avoice fits

Part K figures end up in stair schedules, balustrade specifications and glazing clauses, often copied from an old project.

Avoice Regulations holds the full Approved Document K as a searchable library, so a question such as "what guarding height applies to a Juliet balcony" comes back with an answer that cites the Approved Document. Inside Avoice Practice, QA/QC review checks drawings and specifications against requirements, so a 900mm balustrade on an external balcony or a 175mm general access riser gets flagged before issue. Avoice's State of UK Specifications 2026 report shows how often this kind of error reaches tender.

Software can retrieve, compare and flag. The architect and building control still decide what the project requires.