Private stairs: rise, going and headroom
The geometry is simple and unforgiving. Get the floor-to-floor dimension wrong and the whole flight is wrong.
Short answer
For a private stair in a dwelling, each rise is between 150mm and 220mm, each going between 220mm and 300mm, all rises equal and all goings equal, with a maximum pitch of 42 degrees, a minimum 2000mm headroom measured vertically above the pitch line, and guarding at least 900mm high on flights and landings.
Key figures
| Requirement | Value | Basis |
|---|---|---|
| Rise | 150-220 mm, all equal | Approved Document K |
| Going | 220-300 mm, all equal | Approved Document K |
| Maximum pitch | 42 degrees | Approved Document K |
| Headroom above the pitch line | 2000 mm | Approved Document K |
| Guarding height, flights and landings | 900 mm | Approved Document K |
Setting out from the real floor-to-floor
A staircase is manufactured from a stated finished floor-to-finished floor dimension. If the screed thickness changes, the joists deflect, or the upper floor finish is swapped from carpet to engineered board, every rise changes and the top or bottom riser ends up out of tolerance.
Measure the actual floor-to-floor before the stair is ordered and again before it is fitted. It is far cheaper to hold a delivery than to fit a flight that fails on unequal rise.
Headroom and the awkward corners
Headroom is measured vertically from the pitch line, and the pinch point is almost always the trimmer at the top of the flight or a bulkhead over a winder. Loft conversions have a reduced allowance where the stair is under a sloping roof, but that concession does not apply to a standard house stair.
Guarding and gaps
- Guarding at least 900mm high to flights and landings within a dwelling.
- No opening in guarding that allows a 100mm sphere to pass.
- Guarding that does not use horizontal rails that make it climbable in a dwelling occupied by children.
- Handrail height between 900mm and 1000mm measured above the pitch line.
Common questions
Can the bottom riser be different from the others?
No. All rises in a flight must be equal, and an unequal bottom riser caused by a thicker floor finish is one of the most common stair failures at completion.
What is the maximum number of rises in a flight?
A flight between landings in a dwelling should not have more than 16 rises where it serves a utility area, and general guidance limits long unbroken flights; a landing is provided at the top and bottom of every flight.
Is 2m headroom needed everywhere on the stair?
Yes on a normal house stair, measured vertically from the pitch line across the full width. Reduced headroom is only permitted in the specific loft conversion case described in Approved Document K.
Basis in regulation
Last reviewed 2026-08-21.