Staircase Construction: Rise, Going, Pitch and Part K Compliance

Quick Answer: A domestic staircase in England must comply with Approved Document K: maximum rise 220mm, minimum going 220mm, pitch ≤42°, minimum headroom 2.0m. The 2R+G formula (twice the rise plus the going) should fall between 550mm and 700mm for comfort. Balustrade height ≥900mm with no opening that a 100mm sphere can pass through. All risers must be equal and all goings must be equal across a flight.

Summary

Staircase construction is one of the few areas of carpentry where small errors result in either a Building Control rejection or a serious injury hazard. Every rise must be equal, every going must be equal, the pitch must be within the regulated range, and the headroom must be clear. A staircase that is "close enough" is not close enough — Approved Document K (Protection from falling) is prescriptive for dwellings and Building Control inspectors check the geometry as a priority.

For tradespeople building stairs on site, the calculation work happens before the first cut. You measure the total floor-to-floor height, divide by an estimated number of risers to get a target rise, refine, then work out the going. The risers must divide the total height exactly (no half-step at the top or bottom), and the goings must fit the available horizontal space (the "stair well" length). Once geometry is set, the stringer marking, tread and riser machining, and assembly follow standard timber carpentry practice.

This article covers domestic staircases (single dwelling, private stair). Approved Document K has different rules for "common" stairs (shared escape from flats), "utility" stairs (workplaces), and "general access" stairs (public buildings). The geometry is more permissive for private dwellings and stricter for public access. See staircase for a stair calculator and staircase regs for full regulation reference.

Key Facts

Quick Reference Table

Spending too long on quotes? squote turns a 2-minute voice recording into a professional quote.

Try squote free →
Floor-to-Floor Height Risers Rise per step Going (typical) Total Run (going × goings)
2400mm 12 200mm 230mm 2530mm
2500mm 13 192mm 240mm 2880mm
2600mm 13 200mm 230mm 2760mm
2700mm 14 193mm 240mm 3120mm
2800mm 14 200mm 230mm 2990mm
2900mm 15 193mm 240mm 3360mm
3000mm 15 200mm 230mm 3220mm
3100mm 16 194mm 240mm 3600mm
3200mm 16 200mm 230mm 3450mm

Going count = risers − 1 (last "going" is the landing at the top).

Detailed Guidance

Step 1: Measure total height

Measure floor-to-floor height (top of finished lower floor to top of finished upper floor) at the position the stair will sit. Take three measurements (each end and centre of the planned stair). Use the largest if there's variation — the stair must work with the worst case.

Step 2: Choose number of risers

Divide the height by 200mm to get an approximate riser count. For 2700mm height: 2700 / 200 = 13.5 — so either 13 risers (rise = 208mm) or 14 risers (rise = 193mm). Choose the option giving a rise within range and a comfortable 2R+G total.

Quick sizing check:
  Target rise:    180–200mm (most comfortable)
  Max rise:       220mm
  Target going:   240–280mm
  Min going:      220mm
  2R+G target:    600–650mm

For 14 risers at 193mm with 250mm going: 2 × 193 + 250 = 636mm ✓ comfortable.

Step 3: Check pitch

Pitch = arctan(rise / going). For 193 rise / 250 going: tan = 0.772, pitch = 37.7° — within 42° max ✓.

Step 4: Calculate stair well

Total horizontal run = (risers − 1) × going + nosing projection. For 14 risers × 250mm = 3,250mm minimum. Add 50mm for nosing if used. Confirm the stair well is long enough — if not, redesign with fewer risers (steeper) or add a half-landing.

Step 5: Check headroom

The headroom must be 2.0m above the pitch line for the whole flight. Where the stair runs under a sloping ceiling (typical loft conversion), check that the 2.0m clearance is met at every point along the flight.

Headroom check (loft conversion):
                       ___________
                      /          /|
                     /          / |
                    /          /  |
                   /__________/   |
                       2.0m       |
                        ↕         |
                  ─────────────── 
                  (stair pitch line)

If ceiling slope intercepts the 2m line, redesign.

The exception in Part K allows reduced headroom (≥1.9m at centre of stair, ≥1.8m at side) for loft conversions only.

Step 6: Stringer marking

With the rise (R) and going (G) confirmed, mark the stringers. Use a roofing square with the rise on one blade and the going on the other. Mark with a knife or sharp pencil — every line must be cut exactly once with no doubling.

For each step:

  1. Set the square to R on the short blade and G on the long blade
  2. Slide along the stringer until both blades touch the top edge
  3. Mark along both blades
  4. Slide forward to the next position, repeat

The first rise from floor level is reduced by the tread thickness if the tread is housed into the stringer; the top rise into the landing is reduced by the landing thickness above the joist (typically 22mm).

Step 7: Tread and riser machining

For a glued and screwed stair, mortise the treads and risers into the stringer (8–10mm housing depth) or use a housed and wedged construction. The tread nosing projects typically 16–25mm beyond the riser, with a return mould or chamfer for hand grip when carpeted.

Risers screwed and glued to back of tread. Treads screwed and glued from underneath through tread into stringer housing. Wedges driven in from below for a wedged stair.

Step 8: Assembly

Assemble inverted on a flat surface where possible. Apply PVA glue (PVA Class D3 for interior). Drive wedges or screws. Check for square at every step.

If pre-assembled in workshop, deliver to site and lift into position. If built in situ, fix the bottom stringer to the floor with angle bracket and the top to the trimmer joist.

Step 9: Balustrade

Newel posts at top and bottom (and at any turn or landing). Newel size typically 80–100mm square. Tenoned into floor or trimmer below. Handrail rebated and screwed into newel.

Spindles (balusters) at 100mm centres or closer to satisfy the 100mm sphere rule. Spindle size typically 32 × 32mm. Top fixed to handrail, bottom into a base rail or directly into the tread/string.

Handrail at 900–1000mm above pitch line on the flight. On landings, 900mm above FFL (1100mm if landing is >600mm above floor below — Part K).

Step 10: Building Control inspection

Building Control inspects the staircase at first fix (geometry, structural fixing) and finish (balustrade, handrail). Have the calculation sheet, drawing and rise/going tape measure ready. Common rejection reasons:

Frequently Asked Questions

What if the rise calculation gives an awkward decimal?

Round to the nearest mm and adjust the rise count if needed. Example: 2675mm height / 13 risers = 205.77mm. Round to 206mm × 13 = 2678mm — 3mm tall, planed off the bottom step. Or 14 risers = 191.07mm. Round to 191mm × 14 = 2674mm — 1mm short, added to landing nosing. Either approach is acceptable. What you must NOT do is have one different riser to make the numbers work.

Can I have open risers?

Yes, with the caveat that no 100mm sphere can pass through any opening — including the gap between treads. Most open-riser stairs need either a partial backing board or a small lip to satisfy this. Open risers are common in modern designs and acceptable for primary stairs in dwellings.

Are tapered (winder) stairs allowed?

Yes. Tapered treads ("winders") count for the going measurement at the 270mm walking line. The going at the walking line must still be ≥220mm. Three winders at 30° each replace a quarter landing. Geometry is more complex — use a stair calculator or template. The tapered stair is structurally weaker and typically needs additional support to the centre.

What about a kite winder vs a quarter landing?

A kite winder occupies less floor area but is harder to walk safely (the inner edge of the winder is very narrow). A quarter landing (a flat platform with the stair turning 90°) is preferred for safety and for moving furniture. Geometry of a kite winder: three triangular treads forming a quarter turn, sharing a common corner point.

Are spiral stairs allowed as the primary stair?

Approved Document K does not prohibit spiral stairs as a private dwelling stair, but the going at the walking line must be ≥145mm and structural support must be designed. In practice, spiral stairs are usually secondary (loft access, garden flat) rather than primary because of the difficulty moving furniture and the discomfort of regular use. Section K1.7 of AD K covers spirals.

Does the staircase affect fire compartmentation?

Yes — Part B requires the staircase enclosure to provide a protected escape route. For two-storey dwellings, walls and doors enclosing the staircase must be at least 30 minutes fire-resisting. For three-storey dwellings, all habitable rooms must open onto the stair enclosure or have a separate escape, and the stair enclosure must be 30 minutes throughout. Open-plan ground floors complicate this — see open plan staircase.

Regulations & Standards