If you’re planning a house extension with accessibility in mind, you’ll almost certainly come across the term “Part M compliance.” Understanding what it means, and how it applies to your project, is an important part of ensuring your extension is both legally sound and genuinely fit for purpose.
What is Part M of the Building Regulations?
Part M is the section of the UK Building Regulations that covers “Access to and Use of Buildings.” Its purpose is to ensure that buildings are designed and constructed in a way that allows people to approach, enter, and use them regardless of their age, disability, or mobility. It applies to new buildings and, crucially for homeowners, to certain types of extensions and alterations to existing properties.
Part M is divided into volumes. Volume 1 covers dwellings – the residential properties that most extension projects involve. Within this, there are three categories of accessibility standard: M4(1) Visitable Dwellings (the baseline standard), M4(2) Accessible and Adaptable Dwellings, and M4(3) Wheelchair User Dwellings, which sets the most comprehensive requirements for fully wheelchair-accessible homes.
When Does Part M Apply to a House Extension?
For most standard home extensions, adding a kitchen, extra bedroom, or living space, Part M requirements are relatively limited. However, where an extension is specifically designed to improve accessibility, or where a new entrance or habitable space is being created, more detailed compliance considerations come into play. Extensions that create a new principal entrance, for example, will need to meet accessibility requirements for approach, threshold, and door width.
Where homeowners are specifically extending to accommodate a wheelchair user or to create a fully accessible suite of rooms, it’s common practice, and often required by local planning authority conditions, to design to M4(3) standard. This governs everything from turning circles in bathrooms and kitchens to the gradient of any ramps, door widths, switch heights, and wet room drainage design.
Why Getting it Right Matters
Designing to the correct Part M standard from the outset avoids costly remedial work later and ensures the extension genuinely serves the needs of the person using it. It also provides certainty at Building Control sign-off, which protects your investment and the value of your property.
At Simply Extend, working alongside Simply Architects, we ensure that every accessibility-focused extension is designed with full Part M compliance built in from the very first drawing – not treated as a box-ticking exercise, but as the framework for genuinely excellent, usable design.
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