Bedrooms and bedspaces are different
The Nationally Described Space Standard classifies a home by bedrooms, potential bedspaces and the number of floors within the dwelling. A two-bedroom flat for three people has a different minimum area from a two-bedroom flat for four. These are design classifications, not instructions about who must occupy the home. [3]
For a dwelling on one floor, examples are:
- One bedroom, one person: 39m², or 37m² with a shower room instead of a bathroom.
- One bedroom, two people: 50m².
- Two bedrooms, three people: 61m².
- Two bedrooms, four people: 70m². [3]
Use the correct row for a maisonette extending over more than one floor; the one-storey figures do not automatically apply. [3]
Measure the whole standard
Gross internal area is measured between the internal faces of the walls enclosing the dwelling. It includes internal partitions, structural elements and specified circulation and storage space. Measure each flat separately rather than allocating a share of a communal hall to its internal area. [3]
The standard also controls bedroom dimensions and built-in storage. Its single-bedroom minimum is 7.5m² with a width of at least 2.15m; a double or twin bedroom requires at least 11.5m², with further width requirements. Passing the total-area test does not cancel these separate tests. [3]
These planning standards are not the national minimum sleeping-room conditions for licensed HMOs. Applying the HMO single-adult figure to a new self-contained flat would answer the wrong question. [3] [4]
London adds housing-quality requirements
London Plan D6 specifies a floor-to-ceiling height of at least 2.5m over at least 75% of a dwelling's gross internal area. That is different from the 2.3m figure in the national standard. Assess the existing conversion's sections early, alongside daylight, privacy, outlook and external amenity space. [1] [3]
The desired unit mix is also a policy question. A borough may require family accommodation to remain, so a layout consisting only of small flats is not justified merely because each passes its area test. [2]
What changed in March 2026?
The London support package published on 25 March 2026 withdrew Housing Design Standards guidance C4.1 on dual aspect and B2.5 on eight homes per core. It explicitly retained London Plan D6. This is not a general suspension of space standards or housing quality. [5]
Present a coordinated schedule
Record each flat's bedrooms, bedspaces, floor area, storage and relevant height information. Cross-reference that schedule to the plans and sections, and explain any policy-specific constraints rather than hiding them within a total building area. [3] [1]
Review emerging policy separately: the draft replacement London Plan was still under consultation on 2 October 2026 and should not be described as adopted. [6]