Do I Need Planning Permission?

General guidance for property owners in England. Last reviewed: 12 September 2026

General information, not a decision on any specific property. Confirm your position with your local planning authority before starting work. See our AI Disclaimer.

The short answer: it depends on precise numbers

England's planning system grants automatic permission — called permitted development rights — for many common household projects. Whether your project qualifies is not a matter of judgement or luck: it comes down to specific, published limits. How many metres the extension projects from the rear wall. How high the eaves are. How close to the boundary. How much of the garden the outbuilding covers. Stay inside every applicable limit and no planning application is needed; exceed any one of them and it likely is.

Step 1: What are you building?

• Rear or side extension — often permitted development, subject to depth, height and boundary limits that differ between detached, semi-detached and terraced houses. See our rear extension guide.
• Loft conversion or dormer — often permitted development within volume limits, with stricter treatment of anything facing the street. See our loft conversion guide.
• Garden office or outbuilding — often permitted development if single-storey, within height limits, and not covering more than half the garden. See our garden office guide.
• Changing what the property is used for — different rules entirely; see our change of use guide and HMO guide.

Step 2: Does your property still have its permitted development rights?

This is where many projects come unstuck. The rights attach to the property, and several things remove or restrict them:

• Flats and maisonettes — householder permitted development rights generally apply to houses only.
• Conservation areas — several rights (side extensions, cladding, some roof works) are restricted.
• Article 4 directions — councils can remove specific rights for specific streets or areas. These are easy to miss because they're local orders, not national law.
• Listed buildings — separate consent regimes apply, and permitted development is heavily curtailed.
• Conditions on a previous permission — a past planning approval may have stripped the rights as a condition.

Step 3: Remember Building Regulations apply either way

Planning permission and Building Regulations approval are two separate systems. Even a project that is fully permitted development still needs to comply with the Building Regulations if it involves structural work, new rooms, drainage, or changes to insulation and ventilation — and loft conversions and extensions almost always do.

Getting a definitive-feeling answer without guessing

The frustrating part of general guidance is that everything above says "often" and "depends". That's honest — the real answer for your property depends on your actual dimensions and your actual local designations, checked against the actual limits.

See also: ArchLens for homeowners & developers, Permitted development rights explained, and our AI Disclaimer.