Permitted Development for Outbuildings and Garden Rooms

The height limits that decide most cases

• The height limit is 4 metres for a building with a dual-pitched roof, 3 metres in any other case, and 2.5 metres if any part of the building is within 2 metres of the boundary of the curtilage. (MHCLG, September 2019)

• The 4 metre dual-pitched allowance also applies to hipped roofs with slopes on all four sides. (MHCLG, September 2019)

• Eaves must not exceed 2.5 metres, and height is measured from the highest ground level immediately next to the building to its highest point. (MHCLG, September 2019)

• The building must have a single storey. Anything with more than one storey needs planning permission. (MHCLG, September 2019)

Position and the 50% rule

• Nothing may be placed forward of a wall forming the principal elevation of the original house, including anywhere in front of a hypothetical line drawn through that elevation to the side boundary. (MHCLG, September 2019)

• Buildings, enclosures and containers other than the original house must not cover more than 50% of the curtilage, not counting the ground the original house stands on. (legislation.gov.uk, September 2026)

• Extensions, existing sheds and detached garages all count towards that 50%, including detached buildings put up before 1948. (MHCLG, September 2019)

The use test: garden offices usually pass, bedrooms don't

• Class E only covers buildings required for a purpose incidental to the enjoyment of the house. MHCLG guidance gives sheds, storage buildings, garages and garden decking as examples. (MHCLG, September 2019)

• It expressly does not cover normal residential uses: separate self-contained accommodation, or the use of an outbuilding for primary living accommodation such as a bedroom, bathroom or kitchen. (MHCLG, September 2019)

• Working from home doesn't normally need planning permission if it is incidental to living in the house, so a garden office used by the household is usually covered. If visitors, deliveries, staff or noise change the character of how the property is used, that can be a material change of use, which the council judges as a matter of fact and degree. (MHCLG, July 2023)

• Using a garden room as a bedroom is enough on its own to make it primary living accommodation rather than an incidental building. A shower, toilet or kitchenette doesn't settle it either way: the council looks at how the building is used, which is why many garden annexes need permission even when the structure is within every size limit. (MHCLG, September 2019)

• Outbuildings are not permitted development where the house was created by a permitted development change of use under Class G, M, MA, N, P, PA or Q of Part 3, or built under the Part 20 rights for new homes. (legislation.gov.uk, September 2026)

When Class E does not apply

• Class E only covers houses. In the Order a dwellinghouse does not include a building containing flats, or a flat within one, so a garden building for a flat or maisonette needs planning permission. (legislation.gov.uk, September 2026)

• Nothing within the curtilage of a listed building is permitted under Class E, so a garden building at a listed house needs planning permission. (MHCLG, September 2019)

• A building attached to the house is not covered by Class E. It is treated as an extension under Class A, which has different limits. (MHCLG, September 2019)

• Verandas, balconies and raised platforms are not permitted under Class E. A raised platform is one more than 0.3 metres high. (MHCLG, September 2019)

• A container, such as a heating oil tank, cannot hold more than 3,500 litres. (MHCLG, September 2019)

• Your council can remove these rights with a condition on a planning permission or with an Article 4 direction. What is removed depends on the wording of each one, so check both before relying on Class E. (MHCLG, March 2014)

Conservation areas, National Parks and other protected land

• In a conservation area, National Park, National Landscape (Area of Outstanding Natural Beauty), the Broads or a World Heritage Site, no part of an outbuilding can go between a side wall of the house and the boundary. (legislation.gov.uk, September 2026)

• In a National Park, National Landscape, the Broads or a World Heritage Site, buildings, enclosures, pools and containers more than 20 metres from any wall of the house can cover no more than 10 square metres in total. This cap does not apply in a conservation area. (legislation.gov.uk, September 2026)

Building regulations and the 1 metre rule

• The 1 metre figure comes from building regulations, not planning. A detached single-storey building of up to 30 square metres with no sleeping accommodation is exempt from building regulations if no point of it is less than 1 metre from the boundary, or if it is built substantially of non-combustible material. (legislation.gov.uk, September 2026)

• That exemption has limits. If the building gets its electricity from the house, the electrical work must still meet Part P, so use a registered electrician or check with building control. If it takes water from the house, the Part G rules on water supply still apply. (legislation.gov.uk, September 2026)

• In planning, the boundary distance that matters is 2 metres: if any part of the building is within 2 metres of the boundary, the height limit is 2.5 metres. (MHCLG, September 2019)

• For certainty that a garden building is lawful, a certificate of lawfulness for proposed development gives a formal council decision, and its lawfulness is then conclusively presumed unless there is a material change before work begins. (legislation.gov.uk, September 2026)

Common questions

How tall can a garden room be without planning permission?

2.5 metres if any part sits within 2 metres of a boundary. Otherwise 3 metres, or 4 metres with a dual-pitched roof. Eaves must not exceed 2.5 metres in every case.

Do I need planning permission for a garden office?

Usually not. A home office is incidental to the enjoyment of the house, so it falls within Class E provided the size, position and height limits are met. It changes if the building is used as a bedroom or as self-contained living accommodation.

Can I put a garden room in my front garden?

Not under permitted development. Nothing may sit forward of the principal elevation of the original house, so a front garden building needs planning permission.

Sources