The whole National Park is “Article 2(3) land”
Every house inside Northumberland National Park has narrower permitted development rights: no side extensions, two-storey rear extensions, dormer loft conversions or cladding without planning permission, no prior approval route for larger rear extensions, and garden buildings more than 20 m from the house are capped at 10 m². What Article 2(3) land means →
Article 4 directions in Northumberland National Park
These remove specific permitted development rights in defined areas. Check whether your street is inside one before relying on the national limits.
Northumberland National Park hasn’t published any Article 4 directions to the national planning data platform. That doesn’t mean there are none — check the council’s website (northumberlandnationalpark.org.uk).
From planning.data.gov.uk, Sep 2026. Councils publish at different levels of detail — confirm the scope of any direction with Northumberland National Park.
Conservation areas
Northumberland National Park hasn’t published conservation area boundaries to the national planning data platform yet. The checker will still flag listed buildings and Article 4 directions; for conservation areas, check the council’s own maps.
What you can build in Northumberland National Park
The national limits for a semi-detached house with full permitted development rights.
Getting a Lawful Development Certificate from Northumberland National Park
Apply through the Planning Portal. Decisions usually take up to 8 weeks. Your report tells you whether you need one — and includes the drawings checklist.
Northumberland National Park Authority website ↗Nearby councils