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Part K Stair Dimensions Reference
Rise, going, pitch, headroom, width, handrail and guarding figures read from Approved Document K: Protection from Falling, Collision and Impact, 2013 edition, with the table or paragraph number beside each one.
Rise and Going (AD K 2013 Table 1.1)
Table 1.1 has exactly three rows. There is no separate institutional or assembly row: that category, and the 38 degree pitch and 180mm rise that used to go with it, belong to the withdrawn 1998 edition. Para 1.3 says to use any rise between the minimum and maximum with any going between the minimum and maximum, subject to the relevant note.
| Parameter | Private stair | Utility stair | General access stair |
|---|---|---|---|
| Minimum rise (Table 1.1) | 150 mm | 150 mm | 150 mm |
| Maximum rise (Table 1.1) | 220 mm | 190 mm | 170 mm |
| Minimum going (Table 1.1) | 220 mm | 250 mm | 250 mm |
| Maximum going (Table 1.1) | 300 mm | 400 mm | 400 mm |
| Maximum pitch | 42° (Table 1.1 note 1) | AD K 2013 sets none (the ranges cap it near 37.2°) | AD K 2013 sets none (the ranges cap it near 34.2°) |
| 2R + G | 550 to 700 mm, described in Table 1.1 as the normal relationship between the rise and going. Advisory, not a limit (see below) | ||
2R + G is guidance, not a pass or fail.Table 1.1’s own footnote calls 550mm to 700mm “the normal relationship between the dimensions of the rise and going”, and para 1.3 permits any in-range rise with any in-range going. The extremes of the table break the band: a private stair at 220mm rise with a 300mm going gives 740mm, a general access stair at 170mm rise with a 400mm going also gives 740mm, and a private stair at 150mm rise with a 220mm going gives 520mm. Treat a result outside 550 to 700 as a comfort flag and check it with your building control body.
Two further Table 1.1 notes. Note 2: for dwellings, external tapered steps and stairs that are part of the building need a going of at least 280mm. Note 3: for school buildings the preferred going is 280mm and rise 150mm, which is a preference rather than a requirement.
Which Category Applies (Appendix A)
| Term | Appendix A definition | Table 1.1 row used |
|---|---|---|
| Private stair | “A stair intended to be used for only one dwelling.” | Private stair |
| Utility stair | “A stair used for escape, access for maintenance, or purposes other than as the usual route for moving between levels on a day-to-day basis.” | Utility stair |
| General access stair | “A stair intended for all users of a building on a day-to-day basis, as a normal route between levels.” | General access stair |
| Common stair | “Serving more than one dwelling.” No dimensions of its own. | General access stair, because it is the residents’ normal day-to-day route. Para 1.18 is headed “For buildings other than dwellings and common access areas in buildings that contain flats”, which puts flats inside the utility and general access split |
The practical consequence: a stair in a block of flats is capped at a 170mm rise by Table 1.1 row 3. The 190mm often quoted for this case is the withdrawn 1998 edition, and it is 20mm of extra step height on the shared route of a whole building.
Headroom, Width and Flight Length
| Requirement | Figure | Applies to | Citation |
|---|---|---|---|
| Headroom on the access between levels | At least 2 m | All buildings | Para 1.11, Diagram 1.3 |
| Headroom on means of escape routes | 2 m clear, except in doorways | Buildings other than dwellings, and common access areas in buildings that contain flats | Para 1.12 |
| Reduced headroom where 2 m is not achievable | 1.9 m over the half width of the stair, falling to 1.8 m at the side | Loft conversions in dwellings | Para 1.13, Diagram 1.4 |
| Stair width between enclosing walls, strings or upstands | At least 1,200 mm | Buildings other than dwellings | Para 1.15a. Appendix A defines stair width as “the clear width between the walls or balustrades”, so this is the figure to compare a measured width against |
| Width between handrails | At least 1,000 mm | Buildings other than dwellings | Para 1.15b. A different dimension from the row above, not a substitute for it |
| Dividing a wide flight | A flight more than 2 m wide is divided into flights at least 1,000 mm wide | Buildings other than dwellings | Para 1.15c, Diagram 1.5 |
| Stair width inside a dwelling | AD K 2013 sets no general minimum. The only dwelling figure is 900 mm, and only for a flight within the entrance storey where a severely sloping plot forces a stepped change of level | Dwellings | Para 1.16 |
| Stair width for a common stair in flats | AD K 2013 sets none. Para 1.15 sits under a heading covering buildings other than dwellings only. Escape widths come from Approved Document B | Common access areas in buildings that contain flats | Heading above para 1.15; para 1.14 |
| Change of direction in a long run | More than 36 risers in consecutive flights needs at least one change of direction, at an angle of at least 30° | All buildings | Para 1.17, Diagram 1.6 |
| Maximum risers in a flight between landings | Utility stairs 16. General access stairs 12, exceptionally no more than 16 in small premises where the plan area is restricted. No single steps | Buildings other than dwellings, and common access areas in buildings that contain flats. AD K 2013 sets no per-flight riser cap inside a dwelling | Para 1.18 |
Landings
| Requirement | Figure | Applies to | Citation |
|---|---|---|---|
| Landing at the top and bottom of every flight | Width and length at least as great as the smallest width of the flight | All buildings | Para 1.20, Diagram 1.6 |
| Obstructions | Kept clear of permanent obstructions. A landing may include part of the floor of the building | All buildings | Para 1.21a, 1.21b |
| Cupboard and duct doors over a landing | Allowed at the top of a flight only, and only when kept shut or locked shut in normal use. Diagram 1.7 shows 400 mm minimum | All buildings | Para 1.21c, Diagram 1.7 |
| Landing gradient | Level, except a landing formed by the ground, which may fall at most 1:60 along the direction of travel on paved or permanently firm surface | All buildings | Para 1.22 |
| Unobstructed landing length | At least 1,200 mm on each landing | Buildings other than dwellings | Para 1.23a |
| Doors swinging across a landing | Not permitted, other than the cupboard and duct case above | Buildings other than dwellings | Para 1.23b |
| Doors swinging across a landing | A door may swing across a landing at the bottom of a flight only as shown in Diagram 1.8, which keeps at least 400 mm clear across the width of the flight | Dwellings | Para 1.24, Diagram 1.8 |
Handrail Heights (paras 1.34 to 1.37)
| Requirement | Figure | Applies to | Citation |
|---|---|---|---|
| Top of handrail above the flight | 900 mm to 1,000 mm from the pitch line or floor | All buildings | Para 1.34a |
| Handrail as guarding | The handrail may form the top of a guarding if the heights can be matched | All buildings | Para 1.34b |
| Handrail on both sides | Required if the stairs are 1,000 mm or wider | All buildings | Para 1.34c |
| Continuous handrails on flights and landings | Both sides. Diagram 1.11 (flats) shows 900 mm on the flight and 1,000 mm at the landing; Diagram 1.12 (other buildings) shows 900 mm to 1,000 mm above the pitch line and 900 mm to 1,100 mm at the landing | Buildings other than dwellings, and common access areas in flats without passenger lifts | Para 1.35, Diagrams 1.11 and 1.12 |
| Second, lower handrail | 600 mm from the pitch line to the top, where there is full-height structural guarding | Buildings other than dwellings | Para 1.36a |
| Handrail profile | Circular 32 mm to 50 mm diameter, or non-circular 50 mm wide and 39 mm deep with rounded edges, and 50 mm to 75 mm clear of the wall | Buildings other than dwellings | Para 1.36g, Diagram 1.13 |
The 1,100 mm figure frequently attached to handrails is a guarding height from Diagram 3.1 (below), not a handrail height on a flight. The one place AD K puts 1,100 mm on a handrail is at a landing in a building other than a dwelling, Diagram 1.12, where the range is 900 mm to 1,100 mm.
Guarding Heights (Diagram 3.1)
Para 1.38 sends stair guarding to Diagram 3.1, and para 3.2a repeats it for guarding generally. The heights are set by building category, not by whether the element is a stair.
| Building category | Location | Minimum height |
|---|---|---|
| Single family dwellings | Stairs, landings, ramps, edges of internal floors | 900 mm |
| Single family dwellings | External balconies, including Juliette balconies, and edges of roof | 1,100 mm |
| Factories and warehouses (light traffic) | Stairs, ramps | 900 mm for flights, otherwise 1,100 mm |
| Factories and warehouses (light traffic) | Landings and edges of floors | 1,100 mm |
| Residential, institutional, educational, office and public buildings (this is where a block of flats sits) | All locations | 900 mm for flights, otherwise 1,100 mm |
| Assembly and retail | Within 530 mm in front of fixed seating | 800 mm |
| Assembly and retail | All other locations | 900 mm for flights, otherwise 1,100 mm |
| Glazing in all buildings | At opening windows, except roof windows in loft extensions | 800 mm |
| Requirement | Trigger | Citation |
|---|---|---|
| Guarding at the sides of flights and landings, dwellings | A drop of more than 600 mm | Para 1.41 |
| Guarding at the sides of flights and landings, other buildings and common access areas in flats | Two or more risers | Para 1.40 |
| 100 mm sphere must not pass through openings in guarding, and no readily climbable horizontal rails | A building that may be used by children under five years of age | Paras 1.39 and 3.3 |
| 100 mm sphere must not pass through open risers | Open-riser steps in dwellings, which must also overlap treads by at least 16 mm | Para 1.9 |
Guarding loads come from BS EN 1991-1-1 with its UK National Annex and PD 6688-1-1, with further design guidance in BS 6180 (para 3.2c and its note).
Scotland & Northern Ireland
Everything above is Approved Document K, which applies in England. Scotland uses the Technical Handbooks, Section 4.3 (Stairs and ramps), and Northern Ireland uses Technical Booklet H. Both cover the same ground with their own figures, so check the relevant jurisdiction rather than assuming the AD K numbers carry across.
Related Calculators
Use the Part K Stair Calculator to check a proposed stair against the figures on this page, the Staircase Calculator for full stair design, or the Part M Ramp Gradients page for accessible ramp requirements.
Figures read from Approved Document K: Protection from Falling, Collision and Impact, 2013 edition (as published on gov.uk). Approved Documents are amended periodically, so check the current edition on the Planning Portal (planningportal.co.uk) before relying on any figure here.
Next up: related pages
Frequently Asked Questions
A private stair serves only one dwelling (Appendix A). AD K 2013 Table 1.1 gives it a rise of 150mm to 220mm and a going of 220mm to 300mm, and note 1 caps the pitch at 42 degrees. Para 1.3 lets you pair any rise in that range with any going in that range. The 2R+G figure (twice the rise plus the going, 550mm to 700mm) is described in the table as the normal relationship between the two dimensions rather than as a limit, so treat it as a comfort check and not a pass or fail. Note 2 adds one further figure for dwellings: external tapered steps and stairs that form part of the building need a going of at least 280mm.
Appendix A defines a common stair only as one serving more than one dwelling, and gives it no dimensions of its own. It is the residents’ normal day-to-day route between levels, which is the Appendix A definition of a general access stair, and para 1.18 applies the utility and general access split to common access areas in buildings that contain flats explicitly. So Table 1.1 row 3 governs: rise 150mm to 170mm, going 250mm to 400mm. AD K 2013 sets no maximum pitch for this row, because the rise and going ranges already cap it at about 34.2 degrees. It also sets no width for a common stair: para 1.15 and its 1200mm figure sit under a heading covering buildings other than dwellings, and where AD K means to include flats it says so (compare the heading above para 1.18). Escape widths come from Approved Document B (para 1.14).
At least 2m on the access between levels, in all buildings, measured vertically from the pitch line (para 1.11 and Diagram 1.3). For a loft conversion in a dwelling where there is not enough space for that, para 1.13 and Diagram 1.4 allow 1.9m over the half width of the stair falling to 1.8m at the side. A flat 1.8m across the whole width is not what the diagram shows. In buildings other than dwellings, and in common access areas in buildings that contain flats, means of escape routes need 2m clear headroom except in doorways (para 1.12).
Position the top of the handrail 900mm to 1000mm from the pitch line or floor, in all buildings (para 1.34a), and provide a handrail on both sides if the stairs are 1000mm or wider (para 1.34c). Guarding is a separate element at different heights, set by Diagram 3.1 through paras 1.38 and 3.2a: in a single family dwelling, 900mm on stairs, landings, ramps and edges of internal floors, rising to 1100mm on external balconies, Juliette balconies and edges of roof; in residential, institutional, educational, office and public buildings, which is where a block of flats sits, 900mm for flights and 1100mm everywhere else. The 100mm sphere rule is not universal: paras 1.39 and 3.3 apply it in a building that may be used by children under five years of age, and para 1.9b applies it to open risers in dwellings.
Para 1.29 allows an alternating tread stair in one or more straight flights, but only in a loft conversion, only where there is not enough space for a stair meeting paras 1.2 to 1.24, and only for access to one habitable room plus, if wanted, a bathroom or WC that is not the only WC in the dwelling. Para 1.30 and Diagram 1.10 then set a maximum rise of 220mm and a minimum going of 220mm measured between alternate nosings, uniform steps with parallel nosings, slip-resistant treads, treads over the wider part of the step in line with Table 1.1, no open riser that passes a 100mm sphere, and a minimum clear headroom of 2m. Headroom on an ordinary loft stair may reduce to 1.9m over the half width falling to 1.8m at the side (para 1.13, Diagram 1.4). Para 1.32 allows a fixed ladder with handrails on both sides on the same one-habitable-room condition. Escape provisions come from Approved Document B (paras 1.19 and 1.31).
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Last updated: August 2026
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