What is the maximum rise and minimum going for a private stair?

For a private stair (within a single dwelling), the maximum rise is 220 mm and the minimum going is 220 mm. The pitch must not exceed 42 degrees. Additionally, the rise and going must satisfy the relationship: 2R + G should be between 550 mm and 700 mm (where R = rise and G = going). These requirements are in AD-K Section 1.2 and Diagram 1.2.

What are the dimensions for a common stair in flats?

A common stair (shared between dwellings, such as in a block of flats) has stricter requirements: maximum rise 190 mm, minimum going 250 mm, and maximum pitch 38 degrees. The minimum clear width is 900 mm (1,200 mm if the stair is a firefighting stair). These dimensions ensure safer use by a wider range of occupants.

What headroom is required above a staircase?

The minimum headroom measured vertically above the pitch line is 2.0 m for a private stair and 2.0 m for a common stair. At the edge of the stair (landing or doorway), headroom must also be at least 2.0 m. A reduced headroom of 1.8 m is permitted on a loft conversion stair where there is insufficient space, provided the 1.8 m clearance is maintained over at least the centre of the stair.

What height should handrails and guarding be?

Handrails on stairs must be between 900 mm and 1,000 mm above the pitch line. Guarding (balustrading) on stairs must be at least 900 mm high. On landings, balconies, and edges of floors more than 600 mm above the level below, guarding must be at least 1,100 mm high. Guarding must not have openings that would allow a 100 mm sphere to pass through (to prevent small children getting through).

Are there different rules for loft conversion stairs?

AD-K permits a space-saving stair or alternating tread stair for a loft conversion serving a single room, provided a conventional stair cannot be fitted. These have specific design requirements. Reduced headroom of 1.8 m may be accepted where the structure limits available height. The stair must still meet fire escape requirements per AD-B, which typically means a protected enclosure.

Part K Stair Dimensions Reference

Staircase rise, going, pitch, headroom, handrail, and guarding requirements, referencing Approved Document K: Protection from Falling, Collision and Impact (2013 edition).

Stair Dimensions — Private vs Common (AD-K Table 1.1)

Parameter	Private Stair	Common Stair (Flats)	Utility / Institutional
Maximum rise	220 mm	190 mm	190 mm
Minimum going	220 mm	250 mm	250 mm
Maximum pitch	42°	38°	38°
Minimum width	800 mm (600 mm loft)	900 mm	1,200 mm
Minimum headroom	2,000 mm	2,000 mm	2,000 mm
2R + G range	550-700 mm	550-700 mm	550-700 mm

Handrail and Guarding Heights (AD-K Section 1.5-1.6)

Location	Handrail Height	Guarding Height
Private stair (flight)	900-1,000 mm	≥ 900 mm
Common stair (flight)	900-1,000 mm	≥ 900 mm
Internal landing (private)	N/A	≥ 900 mm (external balcony: ≥ 1,100 mm)
Landing / balcony (common)	N/A	≥ 1,100 mm
Floor edges, galleries, balconies (> 600 mm drop)	N/A	≥ 1,100 mm
100 mm sphere test	N/A	Applies to all guarding

Landing Requirements

Requirement	Private Stair	Common Stair
Landing at top and bottom	Required	Required
Landing length (min.)	Equal to stair width	Equal to stair width
Max. risers in one flight	36 (no limit for private with handrails)	16 (then landing required)
Door swing over landing	400 mm clear landing must remain	400 mm clear landing must remain

Scotland & Northern Ireland

Scotland follows Technical Handbook Section 4.3 (Stairs and ramps) with very similar dimensions but some differences in guarding heights and spiral stair provisions. Northern Ireland uses Technical Booklet H. Always check the relevant jurisdiction for exact dimensions.

Related Calculators

Use the Staircase Calculator for full stair design, or the Part M Ramp Gradients page for accessible ramp requirements.

Always check the latest edition of Approved Documents on the Planning Portal (planningportal.co.uk) as regulations are updated periodically.

How We Calculate This

Frequently Asked Questions

Last updated: April 2026

All calculations are estimates. Verify with your supplier.

Part K Stair Dimensions Reference

Stair Dimensions — Private vs Common (AD-K Table 1.1)

Handrail and Guarding Heights (AD-K Section 1.5-1.6)

Landing Requirements

Scotland & Northern Ireland

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How We Calculate This

Frequently Asked Questions

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