Housing space standards: NDSS, accessibility and HMO bedrooms

Space standards are easy to muddle because several different rules use similar language. For ordinary new homes, the main planning benchmark is the nationally described space standard (NDSS). HMOs have a separate set of minimum sleeping-room sizes imposed through housing licensing legislation, explained on our HMO minimum bedroom sizes page.

The distinction matters. The NDSS is a planning standard, not a Building Regulation. HMO bedroom sizes are licensing standards and do not decide whether a property has planning permission to be used as an HMO. Building Regulations can affect matters such as access, stairs, fire safety and ventilation, but they are a separate regime again. The optional Part M standards now have a much stronger planning role, so see our guide to accessible housing standards M4(2) and M4(3).

Which space standard applies?

• A new home requiring planning permission: check the development plan. A local planning authority can require the nationally described space standard where it has an appropriate local plan policy
• A new home created through permitted development: the relevant GPDO rights that create new dwellinghouses require each new home to meet the applicable minimum space standard, subject to the transitional provisions, even though no full planning application is being made
• An HMO bedroom: licensable HMOs are subject to statutory minimum sleeping-room sizes, and a council can impose higher standards through its licensing regime
• Building Regulations: these are separate. Passing Building Regulations does not by itself prove compliance with the NDSS or an HMO licence, and the reverse is also true

That is why a floor plan can be perfectly buildable but still fail a planning or licensing space standard.

Nationally described space standard for dwellings

The NDSS looks at more than the total floor area. It combines the number of bedrooms and intended bedspaces with minimum gross internal area, bedroom dimensions, built-in storage and floor-to-ceiling height. A one-bedroom, one-person home starts at 39m², or 37m² where it has a shower room rather than a bathroom, but larger households and multi-storey homes require progressively more space.

See our full nationally described space standard guide for the table, bedroom widths, storage rules and the common traps when measuring a proposed dwelling.

HMO minimum bedroom sizes

For HMOs, the national figures are minimum licensing standards for sleeping accommodation. They are not a substitute for checking the rest of the property. A council may also have requirements for kitchens, bathrooms, shared living space, fire precautions and other amenities, and it may require larger bedrooms than the statutory minimum.

The planning question is separate again. A property may need planning permission for HMO use even if every room complies with the licensing standard. See our guide to Use Class C4 and HMOs and our HMO Article 4 map if you are considering a conversion.

Check the local rules before fixing the layout

Do not design right down to a national minimum and assume the job is finished. The local plan may apply the NDSS to new dwellings, an HMO licensing team may publish higher amenity standards, and an Article 4 direction may affect whether HMO permitted development rights are available at all.

Our English Local Authorities directory gives you a quick route to the relevant council and its planning search.

Other Housing Sections

Housing Space Standards Page Updated: 30th August 2026