Scotland Stair Going & Pitch: 225 mm Going, 42° Max

The requirement

For a private stair in a Scottish home, the going must be at least 225 mm. The rise must be 100 mm to 220 mm. The pitch must not go over 42°. The stair must be at least 900 mm wide. Section 4.3 of the Technical Handbook sets these.

Three words do the work here. The rise is how tall each step is. The going is how deep it is. Measure the going from the front edge of one step to the front edge of the next. The pitch is how steep the whole flight sits.

A private stair is one inside a home. It can also be a stair in the grounds of one home that the public cannot get to.

Now the sum. Take the going and add twice the rise. The answer must land between 550 mm and 700 mm.

Watch this trap. You cannot use the tallest rise with the smallest going. A 220 mm rise on a 225 mm going works out steeper than 42°. The handbook rules that pair out. So take one or the other, not both.

Next, width. The 900 mm is the effective width, the clear width you walk on. Two cases go lower. With a handrail up both sides, 800 mm will do. Then there is the 600 mm case. It covers a stair that serves only a toilet. It also covers a stair that serves one other room, with or without the toilet. But that other room must not be a kitchen. It must not be an enhanced apartment. And it must not be an accessible toilet. Table 4.5 sets that out. A string or newel can eat into that width by 30 mm, no more.

Then the flight. A flight can have no more than 16 rises between landings. Most flights need at least 3. A few spots are let off that 3-rise rule. Check section 4.3 for those.

Landings come next. Put a level landing at the top and at the foot of every flight. Each one must be as wide as the flight it serves. The length is 1.2 m, or the width of the stair if the stair is narrower. On a private stair a door may open on to the bottom landing. A cupboard door may open on to the top landing. Either way, leave 400 mm clear across the landing at any angle of swing.

Open risers are allowed on a private stair. Then the treads must lap over each other by at least 15 mm. And a 100 mm ball must not pass through the gap between two treads.

Now the handrail. One side is enough on a private stair. Set the top 840 mm to 1.0 m above the pitch line. The pitch line runs across the front edges of the steps. Leave the other side ready for a second handrail later. It can go on so long as 800 mm of clear width is left.

One case changes all the numbers above. Say the entrance floor is not the main living floor. Say there is no level or sloped way in to that living floor either. Then the stair up to it takes the shallower set. That is a rise up to 170 mm, a going of 250 mm or more, and a pitch of 34° at most. A shared stair in a block of flats takes that shallower set too.

Tapered treads have their own rules. Say a flight mixes straight steps with tapered ones. Then the going of the tapered treads must stay the same all the way up. It must be at least as deep as the going of the straight steps. At the narrow end, the going must be at least 50 mm. That comes from notes 3 and 4 to clause 4.3.2, and clause 4.3.9 says it again.

A flight made all of tapered treads is a helix or a spiral. Build that one to BS 5395: Part 2: 1984. The rise, the width, the rises per flight, the handrails and the barriers all stay as set out above. Clause 4.3.10 covers this.

How Scotland differs from England

England works to Approved Document K. Some numbers match. Some do not.

So a Scottish stair takes 5 mm more going. Scotland lets the rise go lower and the handrail sit lower. Scotland also sets a width and a cap on rises per flight. Doc K sets no cap on rises inside a home. It sets no general width either. It asks for 900 mm in one case only. That is a flight in the entrance storey of a home on a badly sloping plot. Paragraph 1.16 of Doc K covers it.

Those Doc K figures are for England only. Wales runs its own, older Approved Document K from the Welsh Government. We did not check it. Look it up on gov.wales before you work to any of these on a Welsh job.

One last note on which book applies. The April 2026 handbook covers work with a warrant sent in on or after 6 April 2026. Its stair rules did not change in that edition. If your warrant went in earlier, ask your verifier which edition you are on.

Related

• UK stair rules under Doc K sets out the England figures for rise, going, pitch and guarding.
• Building standards in Scotland is the hub for the rest of the Scottish rules.

Sources

• Building Standards Technical Handbook: Domestic, April 2026 edition, Section 4.3 (clauses 4.3.0, 4.3.2–4.3.6, 4.3.14–4.3.16) — guidance under section 4(2) of the Building (Scotland) Act 2003 supporting the Building (Scotland) Regulations 2004. Sets the meaning of “private stair”, the Table 4.3 geometry (min going 225 mm, rise 100–220 mm, tread not less than the going, max pitch 42°, no maximum going), the 2R+G band of 550–700 mm, note 6 barring the maximum rise paired with the minimum going, effective width (Table 4.5: 900 mm; 800 mm with a continuous handrail to both sides; 600 mm where the stair serves only sanitary accommodation and/or one room other than accessible sanitary accommodation, a kitchen or an enhanced apartment; 30 mm max stringer or newel projection), tapered treads (clause 4.3.2 notes 3–4 and clause 4.3.9: uniform going, not less than the going of any straight treads in the same flight, and at least 50 mm at the narrow end; clause 4.3.10: a flight wholly of tapered treads forming a helix or spiral to BS 5395: Part 2: 1984, with rise per 4.3.2, effective width per 4.3.3, rises per flight per 4.3.4, handrails per 4.3.14 and 4.3.15 and barriers per 4.4.2), generally not more than 16 and not fewer than 3 rises per flight, landings (level, width not less than the flight, length 1.2 m or the effective width of the stair, whichever is less, with the 400 mm clear-space door concessions), open risers on a private stair (15 mm tread overlap, no 100 mm sphere through the gap), handrail to one side of a private stair at 840 mm to 1.0 m above the pitch line with provision for a later second handrail at 800 mm clear width, and 2 m minimum headroom. Read it at gov.scot.
• Technical Handbook: Domestic, April 2026 edition, clause 4.2.10 with Table 4.4 (clause 4.3.2) — where the entrance storey is not also the principal living level and there is no level or ramped access to it, the stair from the accessible entrance to that level follows the “any other stair” geometry: max rise 170 mm, min going 250 mm, max pitch 34°. Table 4.4 also covers stairs in the common areas of buildings containing flats or maisonettes. Same publication page at gov.scot.
• Edition in force: the April 2026 edition (Version 1.0, published March 2026) applies to work subject to a building warrant submitted on or after 6 April 2026, and to work not needing a warrant carried out from that date. The official Summary of Changes for 6 April 2026 does not list clause 4.3, so the private-stair geometry is carried forward unchanged. Only the official PDF was used; no working HTML version of section 4.3 for this edition could be resolved. Confirm the current edition at gov.scot.
• Approved Document K: Protection from falling, collision and impact, 2013 edition (England), paragraphs 1.3, 1.11, 1.15–1.18, 1.20–1.24, 1.34 and Table 1.1 — the England comparison figures: rise 150–220 mm, going 220–300 mm, 2R+G of 550–700 mm, max pitch 42° (Table 1.1 note 1), 2 m headroom, handrail 900–1000 mm with both sides required at 1000 mm flight width or more, no general minimum flight width inside a dwelling (paragraph 1.16 sets the only figure: 900 mm for flights within the entrance storey where a stepped change of level is unavoidable on a severely sloping plot), and no per-flight riser cap for a private stair. The 2013 edition is published for use in England (plus excepted energy buildings in Wales) and remains unamended. Read it at gov.uk.
• Not verified here: Wales is covered by a separate, earlier Approved Document K published by the Welsh Government, with its own clause numbering. No Welsh figure was confirmed in this pass, so none is printed above — check the Welsh Approved Document K at gov.wales for a job in Wales. One Scottish point is also unconfirmed and is not stated as a figure on this page: the transitional position for warrants submitted before 6 April 2026. Check the current Technical Handbook and your local verifier directly.