Part M Access: Wheelchair Access and Step-Free Requirements

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Last reviewed: March 2026

What Part M is

Part M is the accessibility bit of Building Regulations. For dwellings it's about getting into the house, moving around inside it, and using key rooms (especially the WC and bathroom) for as many people as possible, including disabled and older people.

The current guidance for homes is in Approved Document M, Volume 1: Dwellings. It sets three "levels" of dwelling:

• Category 1 - Visitable dwellings (baseline for all new homes).
• Category 2 - Accessible and adaptable dwellings (optional, usually set by planning).
• Category 3 - Wheelchair user dwellings (optional, for a percentage of plots where required).

This guide is a summary to make Part M easier to use on site. It does NOT replace Approved Document M: Volume 1 - Dwellings.

You must read and follow the full Approved Document M and any specific planning/access conditions for your project.

This guide is written for England. Wales, Scotland and Northern Ireland have their own versions of building regulations - the principles are similar but the documents and approval routes differ, so check local requirements if you're working outside England.

Part M is about how you build. If you're adapting an existing home for a disabled person, the Equality Act 2010 can also kick in - that's a separate legal duty on landlords and service providers around "reasonable adjustments", not Building Regs.

Where it applies on your jobs

For small builders and trades, Part M crops up all over the place:

• New-build houses and flats - every new dwelling must at least meet Category 1; many sites require Category 2 or 3 via planning conditions or local policy.
• Extensions and major refurbs - especially when you're altering the main entrance, circulation routes, or WCs/bathrooms on the entrance storey.
• Flat conversions - creating new dwellings inside existing buildings still needs reasonable provision for access and use.
• Porches, steps, ramps, thresholds - any change to the approach or entrance can create compliance problems if you make it harder to get in than before.

Volume 1 deals with dwellings. Volume 2 is for non-domestic and common-parts of larger buildings - use that when you're working in shared corridors, lobbies, etc., in blocks.

Key "trigger points" - what actually bites on site

Approach and level threshold (Cat 1/2/3)

• Step-free (or gently ramped) access from parking/road to the main entrance wherever reasonably practicable.
• Level or low-threshold front doors - no big steps people have to climb, and clear widths to get a wheelchair or buggy through.

Entrance storey WC and habitable room

• Category 1: visitor WC and a habitable room (e.g. living room) on the entrance storey, with enough space for someone to get in and use it.
• Category 2/3: bigger WCs with future-proofed drainage for a shower, walls strong enough for grab rails, and clear zones around WC, basin and door.

Circulation: door widths and turning space

• Minimum clear opening widths to doors (often 775-850 mm depending on category and location).
• Enough corridor width and local widening at doorways/turns for wheelchair/buggy to get round corners.

Accessible bathrooms/shower rooms (especially Cat 2/3)

• Bathroom layouts that allow for a future level-access shower, grab rails, and transfer space next to the WC and bath.
• Walls, ducts and boxing built strong enough to take grab rails, seats etc. (typically up to 1.5 kN/m²).

Switches, sockets, controls and storage

• For Category 2 and 3 dwellings, switches, sockets and other controls must sit within the prescribed reach zone (typically 450-1200 mm above finished floor), and be reachable from a wheelchair where required.
• Category 1 doesn't mandate exact heights, but keeping controls roughly in that 450-1200 mm band is good practice and avoids problems if the dwelling is later upgraded or has to meet a stricter standard.

Quick reference table - common jobs

New-build house, "standard" planning condition

• Must meet Category 1 as a minimum: step-free approach where practicable, level threshold, entrance-storey WC and habitable room, basic visitability.
• Check if planning permission also requires Category 2 (very common) - then you're into wider doors, stronger bathroom walls, and future-proofed layouts.

Two-storey rear extension with new open-plan kitchen/living and WC

• Don't lose the entrance-storey WC or make it unusably small; layout must still allow access and use.
• New doors/openings must meet clear width requirements; avoid nibs and tight corners that block wheelchair/buggy access.

Adding a porch and raising the threshold

• You can't introduce a big step or awkward threshold that makes access worse; maintain step-free or gently ramped access where reasonably practicable.
• Door clear opening and handle height must still comply.

New accessible bathroom for client with mobility issues

• Even if planning doesn't formally require Cat 2/3, using those diagrams/layouts is a safe way to get it right: level-access shower, adequate transfer and manoeuvring space, reinforced walls for future grab rails.
• Check door swing, clear width and access from bedroom to bathroom.

Flat conversion in an existing building

• Each new dwelling should meet Category 1 as far as reasonably practicable - step-free access to at least one dwelling or via lift where viable, adequate circulation and WC access.
• Where site constraints make full compliance impossible, you'll need to agree what's "reasonable provision" with Building Control.

Routes to compliance for trades

Use Approved Document M Volume 1 diagrams as your default

For new dwellings, build to Category 1 as a baseline and "upgrade" to Category 2 or 3 where planning requires it. Copy the diagrams for WCs, bathrooms, door clearances, approach routes and thresholds - don't reinvent them.

Check planning conditions early

Many LPA policies require some or all new dwellings to meet Category 2, and a percentage to meet Category 3. If planning says Cat 2/Cat 3 and you build to Cat 1, you've got a major problem at sign-off.

Coordinate with the designer before changing layouts

Moving doors, shrinking WCs, or putting in nib walls can kill the required clearances for turning/manoeuvring. Any change around entrance routes, WCs, bathrooms or main circulation should be checked against the relevant Part M category diagrams.

For existing buildings and tricky sites, agree "reasonable provision" with Building Control

You might not be able to achieve full diagram compliance in an old terrace or tight site. Building Control can accept variations if you can still show that access and use are adequate - but it needs discussing, not assuming.

Who is responsible for what

On a typical domestic project:

• The designer/architect is responsible for drawing a layout that meets the right Part M category for that site and planning permission.
• The builder/main contractor is responsible for actually building to that layout and not nibbling away clearances and widths because "it looks a bit tight".
• Specialist trades - bathroom fitters, door fitters, joiners - are responsible for installing doors, sanitaryware and fittings so the clear zones and reach ranges are achieved.
• The client/owner carries the long-term consequences if the home isn't accessible - harder to sell, may not meet planning obligations, and might not work for their own changing needs.

And the same blunt point as with the other Parts:

If you're the builder running the job and you shrink the WC, lose the level threshold, or fit the wrong doors because "the client wanted it that way", that's on you. When Building Control or planning enforcement push back, you're the one sorting it.

Simple rule to drum into your team

If you're changing the entrance, adding steps, altering door openings, or re-planning WCs/bathrooms, treat it as a Part M issue first. Check the relevant category diagrams before you commit anything to studwork or pipework.

On-site checklist (Part M)

Before you start

• Confirm which Part M category applies to each dwelling: Cat 1 (default), Cat 2 or Cat 3 as per planning.
• Print or keep to hand the relevant diagrams for: approach/parking, thresholds, internal doors, entrance WC, and main bathroom layout.
• Walk the plan and make sure there is a clear, realistic route from entrance to WC and a habitable room on the entrance storey.

While you're working

• Build openings and corridors to the structural widths needed to achieve the clear widths after linings and door frames - don't forget plaster and casing.
• Set WC, basin, bath and shower exactly to the dimensions and zones shown for the category - don't "slide things over a bit" to suit tiling.
• Keep thresholds and approaches low and level; if you have to introduce a step, flag it immediately and get it checked.

When you finish

• Check door clear openings with a tape, not by eye - especially entrance doors, main circulation doors and bathroom/WC doors.
• Check the entrance route: can someone with limited mobility get from the site boundary/parking to the front door without tackling silly steps or tight corners?
• Take photos and measurements of WCs and bathrooms showing clearances and potential future shower space; this can save arguments at sign-off or resale.

Sources

Based on:

• Approved Document M: Access to and use of buildings - Volume 1: Dwellings (2015 edition incorporating 2016 amendments, as updated).
• Planning Portal and LABC summaries of Part M requirements for dwellings and variable categories M4(1), M4(2), M4(3).
• Industry and technical guidance on Part M bathroom layouts, thresholds, reach ranges and accessible dwelling design, plus context on the Equality Act and "reasonable adjustments".

This guide was last reviewed March 2026. SiteKiln does not provide legal, financial or tax advice. All content is for general information purposes only. Always seek professional advice for your specific situation.

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