Glossary
Part K: stair, ramp and guarding rules for London homes
Protection from falling, collision, and impact. Stairs, balustrades, ramps.
Protection from falling, collision, and impact. Stairs, balustrades, ramps.
Approved Document K governs stairs, ladders, ramps, guarding and protection from collision. For a loft conversion it sets the geometry that decides whether a staircase fits at all: a maximum 42-degree pitch, a minimum 220 mm going, a maximum 220 mm rise and 2 m headroom, reducing to 1.9 m at the centre of a loft stair.
A private stair may have a rise of up to 220 mm and a going of at least 220 mm, with the pitch not exceeding 42 degrees. Twice the rise plus the going should fall between 550 and 700 mm. Headroom is 2 m measured vertically from the pitch line, relaxed to 1.9 m at the centre of the stair and 1.8 m at the side for a loft conversion.
That relaxation is what makes most London loft stairs possible, because the new flight usually rises into the slope of the roof.
Only in a loft conversion, only where there is not enough space for a conventional stair, and only where the stair serves a single habitable room — plus, if needed, a bathroom or WC, provided the WC is not the only one in the dwelling. Handrails are needed on both sides.
Guarding to stairs, landings and any floor edge more than 600 mm above the level below. In a dwelling the guarding height is 900 mm for stairs and 1,100 mm for landings and balconies. It must not be climbable and must not allow a 100 mm sphere to pass through.
A worked Bromley example of approved document k (protection from falling): with 48 conservation areas — the Bromley Town Conservation Area and the Chislehurst Conservation Area among the best known — London Borough of Bromley (Bromley Council) sees approved document k (protection from falling) constantly, and there is no borough-wide Article 4 direction, so permitted development generally survives outside conservation areas. Where approved document k (protection from falling) pushes a Bromley scheme out of permitted development, the route becomes a £548 application decided in 8 weeks rather than a £249 prior approval in 6 weeks.
| Maximum pitch | 42 degrees |
|---|---|
| Maximum rise | 220 mm |
| Minimum going | 220 mm |
| Headroom | 2 m, relaxed to 1.9 m centre for loft stairs |
| Guarding height, stairs | 900 mm |
| Sphere gap rule | 100 mm |
Yes if it meets the geometry, but a conventional flight is usually easier to comply with.
Only at the centre of a loft stair, and only where 2 m cannot be achieved.
On stairs over 1 m wide, yes; alternating tread stairs always need two.
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