Staircase building regulations: Northern Ireland
Written by Scott Jones, The Stair Guys, independent staircase measuring and sourcing specialists·Last updated
Northern Ireland does not use England's Approved Document K. Stairs here are governed by Technical Booklet H (Stairs, Ramps, Guarding and Protection from Impact), the 2012 edition, which is the version in force. Most of the figures are close to the rest of the UK, but several differ, and that is exactly where a stair drawn to English figures comes unstuck.
| Measurement | Private stair | Common stair (block of dwellings) |
|---|---|---|
| Minimum rise | 75mm | 75mm |
| Maximum rise | 220mm | 170mm |
| Minimum going | 220mm | 250mm |
| Maximum pitch | 42 degrees | about 34 degrees |
| Max risers per flight | 16 (min 2) | 16 (min 2) |
| Minimum width | 800mm (600mm to one room or a bathroom; 900mm on a circulation route) | 1000mm |
| Headroom | 2000mm (1800mm min in a roofspace conversion) | 2000mm |
| Handrail height | 900 to 1000mm | 900 to 1000mm |
| Guarding height | 900mm | 900mm |
The details that catch people out
As with the rest of the UK, on a private stair the maximum rise (220mm) and the minimum going (220mm) cannot be used together, because that would push the pitch past the 42 degree limit. Open risers must have treads that overlap by at least 16mm, and no gap may let a 100mm sphere through. Headroom is 2000mm over the whole stair, with a relaxation for roofspace conversions down to 1900mm at the centre and 1800mm at the lowest point. A handrail sits 900 to 1000mm above the pitch line and above a landing, and guarding to a dwelling stair is at least 900mm.
Landings
A landing is needed at the top and bottom of every flight, at least as wide as the stair. On a private stair the landing must be at least as deep as the width of the flight, and a door may swing across a landing at the bottom of a flight only where it leaves a clear space of at least 400mm across the full width of the flight (paras 3.17 to 3.18). For the figures across all four nations side by side, see our guide to UK staircase building regulations.
Frequently asked
What building regulations apply to stairs in Northern Ireland?+
Technical Booklet H (2012), Stairs, Ramps, Guarding and Protection from Impact, not England's Approved Document K. It is the edition in force in 2026 and it sets the rise, going, pitch, width, headroom, handrail and guarding figures for stairs in Northern Ireland.
What is the maximum number of steps in a flight in Northern Ireland?+
A flight should have no more than 16 risers and no fewer than 2 (Technical Booklet H, para 3.16). The same 16 limit applies to both a private stair and a common stair in a block of dwellings. The 12-riser figure often quoted is an England general-access rule, not a Northern Ireland one.
What are the rise and going limits for a private stair in Northern Ireland?+
For a private stair, the rise is 75 to 220mm and the going is at least 220mm, with a maximum pitch of 42 degrees. The maximum rise and the minimum going cannot be used together, because the combination would exceed the 42 degree pitch limit.
How high should a handrail be on a Northern Ireland staircase?+
900 to 1000mm, measured above the pitch line of the flight and above a landing (Technical Booklet H, para 3.22). It is not 1100mm; that figure is a guarding height for non-domestic buildings, not a domestic handrail height.
Sources
Primary sources we used and reconciled before publishing.
Related guides
- UK Staircase Building Regulations, ExplainedThe building regulations for stairs in England, Wales, Scotland and Northern Ireland, in plain English. Rise, going, pitch, headroom, guarding and handrails, every figure sourced.
- Staircase headroom: how much you need and how to check itHow much headroom a staircase needs under UK building regulations: the 2 metre rule, the reduced loft-conversion allowance, where headroom is tightest, and how to check it properly.
- Staircase handrail requirements: height, sides and gripWhat UK building regulations require of a staircase handrail: the 900mm to 1000mm height, when you need one side or both, and why a wall-mounted rail needs proper clearance and grip.
- Staircase guarding and balustrade: height and the 100mm ruleWhat UK building regulations require of staircase guarding and balustrade: where it is needed, the 900mm height, the 100mm sphere gap rule, and why it must not be easy for a child to climb.
- Private staircase dimensions: rise, going and pitchThe rise, going and pitch rules for a private (domestic) staircase in the UK, the 2R+G formula, why every rise must be equal, and the simple going = rise divided by 0.9 rule of thumb that keeps a stair within 42 degrees.
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