Definition

Approved Document M is the statutory guidance published to support Part M of the Building Regulations ("Access to and use of buildings"). Volume 1 covers dwellings and divides them into three distinct categories — M4(1), M4(2) and M4(3) — each with its own technical requirements. Volume 2 covers buildings other than dwellings and uses a single, broader standard. For APC purposes, "Part M compliant" is meaningless on its own: a candidate needs to say which category.

Why this matters for Inclusive Environments

Confusing the three categories, or assuming M4(2)/M4(3) apply everywhere, is one of the most common technical errors in Inclusive Environments interviews. Assessors use this topic specifically to test whether a candidate understands the relationship between Building Regulations (a national minimum) and local planning policy (which can require a higher standard on a given site) — two separate regimes that are easy to conflate.

1. M4(1): Category 1 — Visitable dwellings

M4(1) is the mandatory baseline for all new dwellings in England. It requires a reasonably step-free approach from the boundary or parking area, a flush threshold, sufficiently wide doorways and corridors for a visitor to access the entrance storey, and a WC at entrance level. It is designed to make a home visitable by most people, not to make it a fully accessible home for a resident with mobility needs.

2. M4(2): Category 2 — Accessible and adaptable dwellings

M4(2) goes further: level access throughout the entrance storey, wider circulation spaces, a WC and bathroom designed (or easily adaptable) for a wheelchair user, and reinforced walls to allow grab rails to be fitted later without major structural work. It is intended to let an occupier's home be adapted as their needs change, without demolishing and rebuilding.

3. M4(3): Category 3 — Wheelchair user dwellings

M4(3) is the most demanding category, intended for occupiers who are wheelchair users from occupation. It is provided in one of two forms: "wheelchair accessible," ready for immediate occupation by a wheelchair user, or "wheelchair adaptable," built so it can be adapted at reasonable cost. Requirements include step-free access throughout, generous turning circles, and a wheelchair-accessible bathroom and kitchen layout.

4. Where the requirement actually comes from

Only M4(1) is a universal Building Regulations minimum. M4(2) and M4(3) apply only where a local planning authority's adopted policy requires it, almost always as a planning condition on the permission rather than a blanket Building Regulations duty. The London Plan is the best-known example, requiring 90% of new homes to meet M4(2) and 10% to meet M4(3) on qualifying schemes; other local plans set their own percentages or thresholds. A surveyor must check the specific planning permission and condition wording for the site in question, not assume a national standard applies.

Assessor tip

Practise saying the three categories out loud with their plain-English names attached — M4(1) visitable, M4(2) accessible and adaptable, M4(3) wheelchair user — rather than just the numbers. Assessors can tell quickly whether a candidate actually understands the distinction or has just memorised "M4 something."

Relevant RICS guidance and legislation

  • Approved Document M, Volume 1: Dwellings (2015 edition, as amended)
  • Building Regulations 2010, Part M
  • The London Plan (2021), Policy D7 (accessible housing)
  • RICS Inclusive Environments professional statement

Ethics and Rules of Conduct angle

Rule 3 of the RICS Rules of Conduct requires members to provide good-quality and diligent service. Advising a client that a scheme is "Part M compliant" without specifying which category, or without checking the actual planning condition attached to that site, risks giving advice that looks competent but is factually incomplete — a real risk given how often M4(2)/M4(3) requirements are imposed by planning policy rather than the Building Regulations baseline most candidates learn first.

APC questions and answers

Q (Level 1)What is Approved Document M?

Approved Document M is statutory guidance supporting Part M of the Building Regulations, covering access to and use of buildings. Volume 1 applies to dwellings and sets out three categories, M4(1) to M4(3); Volume 2 applies to buildings other than dwellings.

Q (Level 1)What is the difference between M4(1), M4(2) and M4(3)?

M4(1) is the baseline “visitable” standard required for all new dwellings. M4(2) is the “accessible and adaptable” standard, with features like step-free access and a ground-floor WC that can be upgraded without major structural work. M4(3) is the “wheelchair user dwelling” standard, provided either wheelchair accessible or wheelchair adaptable, for occupiers who are wheelchair users from the outset.

Q (Level 2)Is M4(2) or M4(3) mandatory on every new housing scheme?

No. M4(1) is the mandatory national minimum. M4(2) and M4(3) only apply where required by local planning policy or a planning condition — for example, the London Plan requires 90% of new homes to meet M4(2) and 10% to meet M4(3). Without such a policy, M4(1) alone satisfies Building Regulations.

Q (Level 2)A developer client asks why a scheme needs 10% wheelchair user dwellings when the Building Regulations only strictly require M4(1). How would you advise?

I would explain that the M4(3) requirement is not coming from the Building Regulations directly but from the local planning authority's adopted policy — commonly the London Plan or an equivalent local plan policy — which has been applied as a planning condition on the permission. Building Regulations compliance and planning compliance are separate regimes that both have to be satisfied, and non-compliance with the planning condition risks enforcement action regardless of Building Regulations sign-off.

Q (Level 3)How would you check which Approved Document M category applies to a specific unit on a mixed-tenure scheme during a site inspection?

I would start with the approved planning drawings and any condition or section 106 agreement specifying the M4(2)/M4(3) split and which plots they apply to, rather than assuming from the unit's appearance. I would then check the unit against the relevant category's specific technical requirements — for M4(3), for example, confirming step-free access from the point of alighting, corridor and door widths, and a wheelchair-accessible WC/shower layout — and flag any discrepancy between the approved drawings and what has actually been built, since this is a common source of post-completion compliance disputes.