In England, Class E of Part 1 of Schedule 2 to the General Permitted Development Order allows a building within the curtilage of a house for a purpose incidental to its enjoyment, within limits on height, position, storeys and site coverage, and a separate Building Regulations exemption covers small detached buildings.

Class E covers detached buildings, not extensions

Class E of Part 1 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015 permits the provision within the curtilage of a house of any building or enclosure, or swimming or other pool, required for a purpose incidental to the enjoyment of the house as such, and of an oil or LPG heating container. The government’s 2019 technical guidance says a building attached to the house is not permitted under Class E and falls under Class A, the extension rules that also cover conservatories.

The limits in paragraph E.1

Development is not permitted if it would cover more than 50% of the curtilage (excluding the original house) with buildings, enclosures and containers; if any part would be forward of a wall forming the principal elevation of the original house; if the building has more than one storey; or if its height would exceed 4 metres for a dual-pitched roof, 2.5 metres within 2 metres of the boundary, or 3 metres in any other case. The eaves height must not exceed 2.5 metres. The technical guidance says the 50% limit covers all buildings, including extensions under Class A or with planning permission and existing detached buildings, even ones built before 1948, and that the ban on building forward of the principal elevation extends to a line drawn through that elevation to the side boundary.

Class E also does not apply within the curtilage of a listed building, to a verandah, balcony or raised platform, to anything relating to a dwelling or a microwave antenna, or to a heating container over 3,500 litres. It does not apply to a house that was created only through certain change-of-use rights or that was built under the new-dwellings right in Part 20. The technical guidance adds that decking is allowed if not more than 0.3 metres high.

Extra limits on designated land

Paragraph E.2 says that on land in an area of outstanding natural beauty, the Broads, a National Park or a World Heritage Site, development is not permitted if the total ground covered by buildings, enclosures, pools and containers more than 20 metres from any wall of the house would exceed 10 square metres. Paragraph E.3 says that on land subject to article 2(3) of the Order, no part of the building may be between a side wall of the house and the boundary of the curtilage.

What incidental use means

Paragraph E.4 says a purpose incidental to the enjoyment of the house includes keeping poultry, bees, pet animals, birds or other livestock for the occupants’ domestic needs or personal enjoyment. The technical guidance gives garden sheds, storage buildings and garages as examples but says an incidental purpose does not cover normal residential uses such as separate self-contained accommodation, or using an outbuilding for primary living accommodation such as a bedroom, bathroom or kitchen. A garden room used as living space therefore risks falling outside Class E.

Building Regulations exemptions

Schedule 2 to the Building Regulations 2010 exempts small detached buildings in class 6. A detached single-storey building of up to 30 square metres with no sleeping accommodation is exempt if no point is less than 1 metre from the boundary or if it is constructed substantially of non-combustible material. A detached building of up to 15 square metres with no sleeping accommodation is exempt.

Regulation 9 keeps some requirements in play: Part P applies to a class 6 building that receives its electricity from a source shared with or inside a dwelling, and the hot and cold water safety provisions in Schedule 1 apply if its water is shared with a building outside Schedule 2.

FAQs

Can a garden room be attached to the house under Class E?

No. The technical guidance says buildings attached to the house are not permitted under Class E and fall under Class A.

Can a garden office be used as a bedroom?

Not under Class E. The technical guidance says incidental use does not cover using an outbuilding for primary living accommodation such as a bedroom.

Does Class E apply in Scotland, Wales or Northern Ireland?

No. This guide covers England. The other nations have separate planning rules.

Bottom line

A detached garden room in England can be permitted development under Class E if it stays within the height, position, storey and coverage limits and is used for an incidental purpose, and it may sit outside the Building Regulations if it is a class 6 small detached building. Designated land adds limits, and living accommodation falls outside the class. This is general information, not planning advice; the local planning authority can confirm what applies.

Sources

This guide draws on the following primary sources, current as of 21 September 2026:

• legislation.gov.uk, “The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 1”
• Ministry of Housing, Communities & Local Government via GOV.UK, “Permitted development rights for householders: technical guidance” (PDF, September 2019)
• legislation.gov.uk, “The Building Regulations 2010, Schedule 2: Exempt buildings and work”
• legislation.gov.uk, “The Building Regulations 2010, regulation 9: Exempt buildings and work”

Related guides

Compare Conservatories is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not legal or planning advice on any specific property — always confirm requirements directly with your local planning authority.