Areas of Outstanding Natural Beauty have restricted permitted development rights compared to ordinary countryside. Side extensions, larger home extensions and some other works require planning permission that would be PD elsewhere.
In Areas of Outstanding Natural Beauty (AONBs) — now being renamed National Landscapes — some permitted development rights that apply elsewhere in England are restricted or removed. The key restrictions are: side extensions require planning permission (not PD); cladding the exterior of a house in stone, artificial stone, pebble dash, render, timber, plastic or tiles requires planning permission; and the larger home extension Prior Approval scheme (allowing extensions up to 8m/6m) does not apply. The standard rear extensions (up to 4m/3m), loft conversions, and outbuildings are still permitted development in AONBs.
An Area of Outstanding Natural Beauty (AONB) is a landscape designation for areas of countryside in England, Wales, and Northern Ireland that have significant landscape value. There are 34 AONBs in England, covering around 18% of the country. Well-known examples include the Cotswolds, the Chilterns, the High Weald, the Surrey Hills, and the Peak District fringes.
In 2023, the Levelling Up and Regeneration Act renamed AONBs to “National Landscapes” — though many areas still use the AONB name and both terms refer to the same designation. National Parks are a separate, stronger designation with their own National Park Authority.
| PD Class | Restriction in AONB |
|---|---|
| Part 1 Class A — Side extensions | Not permitted development in AONBs — planning permission required |
| Part 1 Class A — Cladding | Not permitted development in AONBs — planning permission required for exterior cladding |
| Larger Home Extension (Prior Approval up to 8m/6m) | Does not apply in AONBs — maximum remains 4m (detached) / 3m (other houses) |
| Part 1 Class B — Loft conversions with side dormer | Side-facing dormers require planning permission in AONBs |
| Part 2 Class A — Gates, fences, walls | Same as elsewhere — up to 1m fronting a highway, 2m elsewhere |
Despite the restrictions, the following works remain permitted development in AONBs:
When PD rights don’t apply in an AONB, you need a planning application. Applications within AONBs are assessed with particular regard to the impact on the natural beauty and character of the landscape. The relevant policy test is in the NPPF: great weight should be given to conserving and enhancing landscape and scenic beauty in AONBs, and development that would have an adverse effect on the designated area should be refused.
In practice, planning applications for modest house extensions within AONBs are often approved where the design is sympathetic to the local vernacular — traditional materials, appropriate massing, and a design that doesn’t jar with the character of the area. Councils are more likely to refuse applications that introduce materials or forms inconsistent with the local building traditions.
Extensions, loft conversions, outbuildings, solar panels — our complete guide covers everything you can build without planning permission.
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