Statutory Nationally Described Space Standards (NDSS) Table for Class MA
Under Article 3(9A) of the Town and Country Planning (General Permitted Development) (England) Order 2015, the grant of any Permitted Development permission for a dwellinghouse is conditional upon every dwelling meeting the 'Technical housing standards – nationally described space standard' (NDSS) published by the Department for Communities and Local Government on 27 March 2015.
If even one flat on your submitted floorplans falls 0.5 sqm below the minimum Gross Internal Area (GIA) or built-in storage threshold, the Local Planning Authority is legally required to refuse Prior Approval.
| Dwelling Size (Bedrooms / Bedspaces) | 1-Storey Flat Minimum GIA (sqm) | 2-Storey Unit Minimum GIA (sqm) | 3-Storey Unit Minimum GIA (sqm) | Minimum Built-In Storage (sqm) |
|---|---|---|---|---|
| 1b1p (Studio with Shower Room) | 37 sqm | N/A | N/A | 1.0 sqm |
| 1b1p (Studio with Bathroom / Tub) | 39 sqm | N/A | N/A | 1.0 sqm |
| 1b2p (1 Double Bedroom Flat) | 50 sqm | 58 sqm | N/A | 1.5 sqm |
| 2b3p (1 Double + 1 Single Bed) | 61 sqm | 70 sqm | N/A | 2.0 sqm |
| 2b4p (2 Double Bedrooms) | 70 sqm | 79 sqm | N/A | 2.0 sqm |
| 3b4p (1 Double + 2 Single Beds) | 74 sqm | 84 sqm | 90 sqm | 2.5 sqm |
| 3b5p (2 Double + 1 Single Bed) | 86 sqm | 93 sqm | 99 sqm | 2.5 sqm |
| 3b6p (3 Double Bedrooms) | 95 sqm | 102 sqm | 108 sqm | 2.5 sqm |
Internal Bedroom Widths & Ceiling Height Rules
Meeting the overall flat GIA is only half of the NDSS statutory requirement. Case Officers also measure the internal geometry of every bedroom and the floor-to-ceiling height:
• Single Bedroom (1 bedspace): Must have a minimum floor area of 7.5 sqm and be at least 2.15 metres wide.
• Double or Twin Bedroom (2 bedspaces): Must have a minimum floor area of 11.5 sqm. The first double bedroom in any flat must be at least 2.75 metres wide, and every subsequent double bedroom must be at least 2.55 metres wide.
• Minimum Ceiling Height: Must be at least 2.3 metres for at least 75% of the Gross Internal Area of the dwelling.
• Headroom Exclusions: Any floor area with a ceiling headroom of less than 1.5 metres (such as under pitched roof eaves) is excluded from the GIA calculation unless used solely for built-in storage.
A 1-person studio flat (1b1p) is only allowed to be 37 sqm if the sanitary room contains a shower cubicle rather than a bathtub. If your architect draws a bathtub inside a 37.5 sqm studio flat, it breaches the NDSS (which requires 39 sqm where a bath is installed) and will be refused!
Natural Light Standards in Habitable Rooms (BRE 209 & BS EN 17037)
Under Paragraph MA.2(2)(f) and Paragraph W(10)(b) of Part 3 of the GPDO, the Local Planning Authority must refuse Prior Approval if the development does not provide adequate natural light in all habitable rooms.
In planning law, a 'habitable room' includes any room used or intended to be used for sleeping, living, or eating (bedrooms, living rooms, dining rooms, studies, and open-plan kitchen-living-diners). Bathrooms, WCs, utility cupboards, entrance hallways, and small standalone galley kitchens (without dining space) are classed as non-habitable rooms and can be positioned in the internal core of a deep-plan building.
Councils assess 'adequate natural light' against the Building Research Establishment (BRE) guide 'Site Layout Planning for Daylight and Sunlight (BR 209, 2022 edition)' and British Standard BS EN 17037, which specify target illuminance levels across at least 50% of the room's working plane for half of the daylight hours:
• Bedrooms: Target illuminance of 100 lux.
• Living Rooms: Target illuminance of 150 lux.
• Kitchens / Open-Plan Kitchen-Living-Diners: Target illuminance of 200 lux.
Architect's Floorplan Design Checklist for Class MA Approval
Before submitting your drawings, verify these five spatial and daylight details: