UKI want to add a conservatory. Do I need planning permission?
In most cases, you do not need planning permission to add a conservatory in the UK — it is usually considered permitted development, provided it meets specific size, height, and location rules.
What the Law Says
Whether planning permission is needed for a conservatory depends not on the Law of Property Act 1925, but on the Town and Country Planning Act 1990 and the General Permitted Development Order (GPDO) 2015 — which sets out 'permitted development' rights. The Law of Property Act 1925 s. 1 is not relevant to planning permission for conservatories; it concerns the creation and conveyance of legal estates in land, not development control.
Adding a conservatory usually falls under 'permitted development', meaning no planning permission is required — as long as it complies with strict limits set out in the GPDO 2015.
Key conditions include: the conservatory must not extend beyond the rear wall of the original house by more than 4 metres (for attached houses) or 3 metres (for detached houses); its height must not exceed 4 metres; and it must not cover more than half the area of land around the original house.
It must also not be forward of the principal elevation facing a highway, and must not include features like verandas, balconies or raised platforms.
Statutory Textc. 20
— Law of Property Act 1925, s. 1
What to Do
Check if your property has had permitted development rights removed (e.g., via an Article 4 direction or listed building status).
Measure your proposed conservatory against GPDO limits: depth, height, position, and volume.
If in doubt, apply for a Lawful Development Certificate from your local planning authority — it confirms whether permission is needed.
Always notify your building control body, as building regulations (not planning permission) still apply to structural safety, insulation, and glazing.
Sources
Not legal advice. This article is general information based on publicly available sources, written for educational purposes. Laws change and individual situations vary. Consult a licensed attorney in your jurisdiction before acting on anything you read here. Last reviewed: 2026-06-08.