ProjectCalcWhich volume
This page is Approved Document M, Volume 1: Dwellings (2015 edition, with the 2016 amendments). Volume 1 is divided into categories of provision: Category 1 covers visitable dwellings, and Category 2 covers accessible and adaptable dwellings, with further provisions for wheelchair user dwellings. The Category 1 provisions apply as a baseline; the higher categories apply where a planning condition or a client requires them.
The measurements below are clear dimensions, measured with the door open. A "clear opening width" is not the width of the leaf you order — it is the gap you actually get.
Doors and corridors
Paragraph 1.15 ties the two together: the width of a corridor depends on the clear opening width of the doorways that open off it.
| Doorway clear opening width | Corridor clear passageway width |
|---|---|
| 750 mm or wider | 900 mm (when approached head on) |
| 750 mm | 1200 mm (when the approach is not head-on) |
| 775 mm | 1050 mm (when the approach is not head-on) |
| 800 mm | 900 mm (when the approach is not head-on) |
Paragraph 1.15 also requires that a localised obstruction such as a radiator does not occur opposite or close to a doorway and is no longer than 2 m, and that the corridor is not reduced below a minimum 750 mm width at any point.
There is a genuinely useful shortcut in the note to the table: "A standard 826 mm door leaf up to 44 mm thick will be deemed to satisfy a requirement for a clear opening width of 775 mm." That is the sentence to reach for when someone asks which door to buy for a 775 mm clear opening.
For a communal entrance to a building containing a dwelling, paragraph 1.9(a) requires the principal communal entrance door to have a minimum clear opening width of 775 mm, measured in accordance with Diagram 1.1.
Handrails
Paragraph 1.8(f): every flight with three or more risers has a suitable handrail to one side, "grippable", 850-1000 mm above the pitch line of the flight, extending a minimum of 300 mm beyond the top and bottom nosings.
Kitchens — the numbers that decide a worktop run
For a Category 1 visitable dwelling, paragraph 2.24 requires a living area within the entrance storey and, at 2.24(b), a minimum 1200 mm clear space in front of and between all kitchen units and appliances. That is the circulation figure that decides whether a galley kitchen works.
For an accessible and adaptable dwelling, paragraph 3.32 raises the clearance: there must be a minimum clear access zone 1500 mm wide in front of, and between, all kitchen units. The same paragraph also requires the kitchen and the principal eating area to be in the same room or connected to each other, and requires the overall length of kitchen worktop to meet Table 3.3 — the minimum worktop length, including fittings and appliances, for a wheelchair adaptable dwelling:
| Number of bedspaces | Minimum worktop length |
|---|---|
| 2 | 4330 mm |
| 3 and 4 | 4730 mm |
| 5 | 5630 mm |
| 6 to 8 | 6730 mm |
The table is measured through the mid-line of the worktop, not the front or rear edge — so it is a length of run, not a length of board. Table 3.4 sets the equivalent figures for a wheelchair accessible layout, which are higher again.
What this changes about the job
- Order the door by its clearance, not its leaf size. A 762 mm leaf does not give a 775 mm opening; the note above is the reason an 826 mm leaf is the usual answer.
- Check the corridor against the door. A wider door can force a wider corridor, and a plan that is 700 mm too narrow is a rebuild, not a decoration.
- Kitchen runs are dimensioned by clearance and worktop length. Work out the clearance the category requires, then the worktop length, then the number of units — in that order.
Last verified 22 September 2026. Every requirement quoted on this page was read from the primary source listed below on that date, not from a summary. If a figure could not be confirmed in the primary source it is not on this page.
Where these figures come from
- Approved Document M, Volume 1: Dwellings, 2015 edition with 2016 amendments (paragraphs 1.8-1.9, 1.15, 2.24, 3.32 and Tables 1.1, 3.3 and 3.4) — GOV.UK publications, "Access to and use of buildings: Approved Document M", checked 22 September 2026.
Guidance only, not advice
This page is a plain-English summary of published regulations and standards, written to help you plan a job. It is not professional advice, it is not a substitute for the actual document, and it is not a building-control decision.
Building regulations are enforced by your local authority (or an approved inspector) and the facts of a particular job can change the answer. Confirm with your local building control before you start work, and where a job is structural, get it designed by a suitably qualified person. If this page and the source document disagree, the source document wins.