A worked example of a compliant general access (commercial) staircase
Written by Scott Jones, The Stair Guys, independent staircase measuring and sourcing specialists·Last updated
Not every staircase is a "private" home stair. A stair in a block of flats, an office or a shop is a general access stair, and Approved Document K holds it to shallower, gentler rules. Here is a worked compliant one, and it shows why you cannot just scale up a domestic design.
| Measurement | This example | General access limit | Private stair, for contrast |
|---|---|---|---|
| Rise | 165mm | 170mm maximum | 220mm maximum |
| Going | 275mm | 250mm minimum | 220mm minimum |
| Pitch | 31 degrees | none stated; rise and going cap it at 34.2 degrees | 42 degrees maximum |
| Risers per flight | 8 (two flights + a landing) | 12 maximum | 16 maximum |
| Headroom | 2m | 2m minimum | 2m minimum |
Why it passes, and why it needs a landing
The geometry clears easily: the 165mm rise is under the 170mm general access maximum, the 275mm going is over the 250mm minimum, and the pitch works out at 31 degrees against the 38 degree limit. Set beside a private stair, you can see how much gentler it is, a shallower rise, a deeper going, a lower pitch.
The catch is the number of steps. A general access flight is limited to 12 risers (16 only in small premises of no more than two storeys). A normal storey height of, say, 2640mm needs 16 risers at 165mm, which is more than 12, so the stair has to be broken into two flights, for example 8 and 8, with a landing between them. This is why general access stairs take up more room than people expect: they are both shallower and, often, split by a landing. Full detail on the categories is on the general access and utility regulations page.
Frequently asked
Can you give an example of a compliant general access or commercial staircase?+
Yes. A general access flight of 165mm rise and 275mm going gives a 31 degree pitch, which is compliant with Approved Document K (rise up to 170mm, going at least 250mm). Because a general access flight is capped at 12 risers, a full storey height usually has to be split into two flights with a landing between them.
How is a general access stair different from a domestic one?+
It is shallower and gentler. A general access stair (used in blocks of flats, offices and shops) allows a maximum 170mm rise and needs a minimum 250mm going, where a private home stair allows 220mm rise, 220mm going and 42 degrees. Approved Document K sets no maximum pitch for a general access stair: the rise and going already cap it at 34.2 degrees. A domestic stair drawn into a shared building is non-compliant, not just tight.
How many steps can a general access staircase have in one flight?+
12 risers, rising to a maximum of 16 only in small premises of no more than two storeys above ground. Because of that cap, a general access stair to a normal storey height usually has to be split into two flights with a landing, unlike a private stair which has no per-flight riser limit.
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