New UK planning rules – what you can now build in your own back garden
Key Points
- The new National Planning Policy Framework took effect in England on 17 August 2026 and applies to planning applications and appeals already lodged but not yet decided.
- Councils must give substantial weight to schemes that add homes or floorspace within settlements, including additional units inside residential curtilages.
- National parameters cap garden development at twice the footprint of existing buildings on the site, with at least half the undeveloped area left undeveloped.
- Permitted development rights have not changed, so garden schemes still need planning permission.
- Older local plan policies that clash with the new national rules should now carry very limited weight.
Homeowners in England have a stronger case for building in their gardens under the new National Planning Policy Framework, published on 17 August 2026 to replace the December 2024 version.
The framework’s decision-making policies became material considerations from the day of publication, and may affect live applications and appeals immediately.
The government has separated policies for plan-making from those for deciding individual applications, and only the second set applies to a householder scheme.
Policy L2 tells decision-makers to give substantial weight to the benefits of creating additional homes or floorspace within settlements.
Some of the the named routes include:
- Using the airspace above existing residential or commercial buildings,
- Adding mansard roofs,
- Filling gaps in existing roof lines,
- Introducing taller buildings at suitable street corners,
- Sensitively redeveloping underused plots,
- Creating additional units within residential curtilages.
Curtilage covers the land attached to a house, which for most properties means the garden.
Notably, the framework sets national parameters for how much of a garden a scheme can occupy.
Development should not ordinarily take up more than twice the footprint of all existing buildings on the site, and at least 50% of the currently undeveloped area within the curtilage should remain undeveloped afterwards.
More may be possible where the site can accommodate it without harm, taking account of local character, infrastructure and the value of sustainable locations.
Policy S4 states that development proposals within settlements should be approved unless the benefits would be substantially outweighed by adverse effects, a materially stronger starting point than the December 2024 Framework, which focused enhanced support more narrowly on suitable brownfield land.
Matthew Pennycook, Minister of State for Housing and Planning, told council leaders in a letter published alongside the new Framework that the government had updated policy to support more types of development within the curtilage of residential properties, and to back extra floorspace rather than only extra units.
Local policies that block this approach may now count for less. Development plan policies that are materially inconsistent with the new national decision-making policies should be given very limited weight, unless they were examined and adopted against this framework.
Age alone is not enough, and the test is material inconsistency assessed policy by policy.
The framework does not itself create or remove permitted development rights, which sit in the General Permitted Development Order.
Garden and backland schemes still require planning permission, and councils still assess access, privacy, daylight, external amenity space, street scene and local character.
The framework also keeps harm from development within residential curtilages as a ground on which councils can refuse.
