Outbuilding Permitted Development Checker

Check in about two minutes whether your shed, garden room, garage or other outbuilding is likely to need planning permission in England.

• Free to use
• Headline result with no sign-up
• Based on the GPDO 2015 Class E rules
• Rules last checked 11th November 2026

Outbuilding permitted development: do you need planning permission?

In England, most sheds, garden rooms, summer houses and detached garages can be built without planning permission under Class E permitted development, as long as they are single storey, sit behind the front of the house, stay within the height limits (2.5 m within 2 m of a boundary, otherwise 3 m, or 4 m with a dual-pitched roof) and, together with other extensions and outbuildings, cover no more than half the garden. This checker tests your plans against each of those rules and flags anything that would mean you need to apply.

How to use this checker

1. Tell us whether the property is a house, whether it is listed and whether it is in a protected area such as a conservation area or National Park.
2. Enter the size of the outbuilding: the ground area it covers, the roof type, the overall and eaves heights, and how close it comes to the boundary.
3. Enter your plot area, the ground area of the original house and any existing extensions or outbuildings, then tick any rule check that applies.
4. Press See my result. Your headline result is free and shows straight away. Add your details to unlock the full working, the Building Regulations points and a free planning report.

The Class E rules explained

Outbuildings fall under Class E of Part 1, Schedule 2 of the Town and Country Planning (General Permitted Development) (England) Order 2015. In plain English, an outbuilding is not permitted development if:

• Coverage: together with other buildings, enclosures and containers, it would cover more than 50% of the curtilage (the house's garden and grounds). The ground under the original house is left out of the sum, but later extensions and existing outbuildings count.
• Position: any part is forward of the principal elevation of the original house, which is usually the front wall facing the road.
• Storeys: it has more than one storey.
• Height: it is more than 2.5 m high when any part is within 2 m of the boundary. Otherwise the limit is 4 m with a dual-pitched roof and 3 m with any other roof. Height is measured from the highest ground next to the building.
• Eaves: the eaves are more than 2.5 m high.
• Raised platforms: it includes a verandah, balcony or a platform more than 0.3 m high.
• Listed buildings: it is within the curtilage of a listed building.
• Use: it is not for a purpose incidental to enjoying the house. The government guidance gives garden sheds, storage buildings and garages as examples. A bedroom, bathroom or kitchen used as primary living space, or a separate self-contained unit, is not incidental.

Extra rules on protected land

• In a National Park, National Landscape (Area of Outstanding Natural Beauty), the Broads or a World Heritage Site, buildings, enclosures, pools and containers more than 20 m from any wall of the house must not cover more than 10 m² in total.
• On any article 2(3) land, which also includes conservation areas, nothing can go between a side wall of the house and the boundary.

The government's permitted development technical guidance for householders explains each rule with diagrams, and the Planning Portal outbuildings guide gives a short summary. Flats and maisonettes do not have these rights, and councils can remove them with an Article 4 direction or a planning condition.

Building Regulations are separate

Under Schedule 2 of the Building Regulations 2010, a detached outbuilding with no sleeping accommodation is usually exempt if its floor area is no more than 15 m². Up to 30 m², a single storey building is exempt if no point is less than 1 m from the boundary or it is built substantially of non-combustible material. Larger buildings, or any with sleeping accommodation, normally need Building Regulations approval.

For more help, read our guides to lawful development certificates, householder planning applications and site and block plans. Planning an extension too? Try our permitted development rear extension calculator or loft conversion volume calculator.

Assumptions and limits

• It covers England only. Wales has its own outbuilding rules, including a 1.5 m height limit within 2 m of the house and extra rules near a highway, and Scotland and Northern Ireland have their own permitted development rules, so this checker does not apply there.
• A building exactly 2 m from the boundary is treated as within 2 m, so the lower 2.5 m height limit is used. If you are close to 2 m, get the position measured accurately.
• Garden coverage uses the figures you enter. Measure from a scaled plan where you can.
• Ground area is measured outside, so it slightly overstates the floor area used for Building Regulations.
• It assumes the outbuilding is detached. A building joined to the house is an extension and falls under different rules.
• Class E also covers pools and oil or LPG tanks (up to 3,500 litres), but this checker is designed for buildings.

Frequently asked questions

Last checked 11th November 2026. This tool gives a guide only, based on the rules published at the date above. It is not professional advice, and your council has the final say.