PERMITTED
DEVELOPMENT

DO I NEED PERMISSION?

Many extensions, loft conversions and garden buildings can be built without a planning application under permitted development rights. These national rules apply to houses, but not to flats or maisonettes.

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The rules are detailed, and a small miscalculation can leave you with work that needs retrospective permission. We check your proposal against them before you build.

REAR EXTENSIONS

A single-storey rear extension can usually project up to 3 metres from the original rear wall of an attached house, or 4 metres for a detached house, with a maximum height of 4 metres.

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Through the prior approval process this can increase to 6 metres or 8 metres. Extensions and outbuildings together cannot cover more than half of the land around the original house.

LOFTS AND OUTBUILDINGS

Loft conversions can add up to 40 cubic metres of roof space on a terraced house and 50 cubic metres on other houses, with nothing on the front roof slope.

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Garden buildings must be single storey, sit behind the front of the house, and be no higher than 2.5 metres within 2 metres of a boundary.

TIGHTER RULES

In conservation areas, National Landscapes such as the Surrey Hills and Chichester Harbour, and the South Downs National Park, permitted development rights are reduced. Side extensions, cladding, rear extensions of more than one storey and loft extensions all need a planning application.

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Councils can also remove rights with an Article 4 direction. And if your home is listed, most work needs listed building consent whatever the planning position.

LAWFUL DEVELOPMENT

A Lawful Development Certificate is formal confirmation from the council that a proposal is lawful. It is not a planning application, so the council looks only at the facts and the rules, not at whether it likes the design.

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We recommend one for most permitted development projects. It protects you if a neighbour complains and answers the first question a buyer’s solicitor will ask. The council fee is half the equivalent planning application fee.

EXISTING WORK

If work was done years ago without permission, a certificate of lawful existing use or development can regularise it.

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For anything substantially completed on or after 25 April 2024 the council can take enforcement action for up to 10 years, so the evidence matters. We help you gather it and present the case.

HAVE THE RULES CHANGED?

Householder permitted development rights have not changed in 2026. The Planning and Infrastructure Act 2025 deals with fees, planning decisions and nature recovery, not house extensions.

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The only change to permitted development this year covered solar panels, in August 2026.

YOUR NEXT STEP

Start with a planning surgery: 45 minutes at our Haslemere office or on Teams, for a flat £95 plus VAT. We research your site’s constraints beforehand, so the time is spent on answers rather than background.

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Prefer to talk first? Call us on 01428 892198. We reply to every enquiry within one working day.