The three dwelling categories
M4(1) concerns visitable dwellings. M4(2) concerns accessible and adaptable dwellings, while M4(3) concerns wheelchair-user dwellings. The higher categories are optional building regulations requirements that can be applied through planning conditions; they should not be treated as merely interchangeable design labels. [2]
Identify the required category for each dwelling before developing the layout. Record it in the accommodation schedule and technical drawings so the approach, entrance, circulation and sanitary arrangements are designed consistently.
London policy matters
London Plan Policy D7 requires at least 10% of relevant dwellings to meet M4(3), with the others meeting M4(2), where the homes are created through works to which Part M Volume 1 applies. The policy's explanation says this generally limits that application to new-build dwellings and provides for specified flexibility agreed at planning stage. [3]
This is a London policy position, not an automatic rule for every flat conversion in England. Epping Forest District is outside London, so its applicable planning requirements and the actual permission need to be checked separately. The national building regulations framework still applies. [3] [1]
Existing buildings require a scope check
Do not assume that an ordinary extension requires every room in the existing house to be rebuilt to M4(2). Approved Document M explains the limits of application and the treatment of relevant alterations, including the principle that applicable provision should not be made less satisfactory. [2]
For non-domestic work, use the appropriate Volume 2 guidance rather than adapting a house's circulation dimensions to a shop, office or shared facility. Building type and the proposed work affect what needs assessing. [1]
Coordinate access with the rest of the design
A level or accessible threshold must also work with drainage and weather protection. Doors and circulation need coordination with fire escape, guarding and the actual structural layout. These are interfaces to resolve together, not competing details left to different installers. [2] [4] [5] [6]
Check clear usable space and the completed arrangement rather than relying only on nominal product sizes. Ask the designer to demonstrate how the relevant layout works with doors, fittings and the intended approach.
Keep the requirements visible through construction
Record the planning condition, required dwelling category and approved technical details. Refer changes to thresholds, doors or sanitary layouts back to the responsible designer before installation. [3] [7]
The final compliance record should show the category and construction actually delivered. Do not describe a proposed national policy change as an enacted universal M4(2) requirement without a verified implementing provision. [1]