Permitted development: what you can build without permission
Permitted development lets you extend, convert, and change use without a full planning application. Here is what the rules actually allow.
What permitted development actually means
Certain types of development are automatically granted planning permission by law, without submitting an application. These rights are set out in the Town and Country Planning (General Permitted Development) Order 2015 (the GPDO). Stay within the limits, and you do not need planning permission.
Key PD rights for residential properties
Rear extensions
Single-storey rear extensions can project up to 4 metres for detached houses and 3 metres for semi-detached and terraced houses. The larger home extension scheme allows up to 8 metres (detached) or 6 metres (semi/terrace) with a prior approval notification. Maximum height is 4 metres.
Side extensions
Permitted provided the extension is no more than half the width of the original house, does not exceed 4 metres in height, and is single storey.
Loft conversions
Volume allowance of 40 cubic metres for terraced houses and 50 cubic metres for detached and semi-detached. Dormers cannot extend beyond the plane of the existing roof slope facing a highway. Materials must match.
Outbuildings
Permitted provided total ground coverage (excluding the house) does not exceed 50% of the curtilage. Maximum height: 2.5m flat roof, 4m dual-pitch, 2.5m if within 2 metres of boundary.
Change of use: commercial to residential
Under GPDO Class MA, you can convert Class E premises (offices, shops, restaurants, light industrial) to residential (C3) via prior approval. The building must have been in Class E use for at least two continuous years and vacant for at least three months.
When PD rights do not apply
Article 4 Directions: Local authorities can withdraw specific PD rights in defined areas. Common in conservation areas and town centres.
Conservation areas: Restrict cladding, dormers on highway-facing slopes, and outbuildings forward of the principal elevation.
Listed buildings: No PD rights for any works affecting the building's character. Listed Building Consent is always required.
AONB and National Parks: Tighter limits on extensions and certain works.
Flats: Very limited PD rights. Most external alterations require planning permission.
The designations that switch permitted development off, conservation areas, listed buildings, Article 4 directions and the rest, are what MarketCode's planning-check skill returns for any address, graded by severity.