Class E outbuildings: sheds, garages and garden rooms

Class E can grant planning permission for outbuildings and other structures used for purposes incidental to enjoying a qualifying house in England. Examples can include a shed, garage, garden gym or hobby room. The actual purpose, size and position matter.

The familiar “2.5 m high” and “half the garden” shortcuts leave out important detail. Near a boundary, 2.5 m is the limit for the whole building, and the 50% calculation concerns the house’s curtilage excluding the original house.

First establish the purpose

The building or structure must be required for a purpose incidental to the enjoyment of the dwellinghouse as such. In everyday terms, it supports the occupants’ enjoyment of the home rather than providing a separate home or ordinary additional living accommodation.

Domestic storage, hobbies, a gym and a suitable home office can qualify, depending on the facts. Class E expressly includes keeping poultry, bees, pets, birds or other livestock for the occupants’ domestic needs or personal enjoyment. It does not grant a general right to commercial kennels, a business premises or a separate dwelling.

There is no fixed Class E maximum floor area for every outbuilding and no universal ratio between the size of the house and outbuilding. However, the proposed scale must be justified by the incidental purpose, and all the coverage and siting limits still apply. Do not treat 50% coverage as an automatic entitlement to a building of that size.

The principle in Emin is that an activity may be incidental in character, but the building must also be genuinely and reasonably required for that purpose in the circumstances of the particular home. Scale is relevant, but not conclusive, and there is no fixed percentage or floor-area formula. Where a building is large for its intended use, explain who will use it, what will happen there and how the proposed layout and space meet that need. A label such as “gym”, “games room”, “home office” or “storage” does not by itself justify an outbuilding of any size.

Sleeping or residential accommodation needs separate assessment. See the annexe guide, which distinguishes permission for the building from the lawfulness of its use. Labelling accommodation a gym or removing a bed does not establish that the original building works were lawful. A Northampton outbuilding annexe appeal also shows how a realistic Class E fallback can carry planning weight even where no lawful development certificate has been obtained, while an ancillary-use condition can prevent a separate dwelling.

What work does Class E cover?

• Provision of a building, enclosure, swimming pool or other pool required for an incidental purpose
• Maintenance, improvement or other alteration of such a building or enclosure
• A container storing oil or liquefied petroleum gas for domestic heating, with a capacity no greater than 3,500 litres

Class E does not cover a dwelling or a microwave antenna. Check Class A for extensions to the house and Class H for satellite dishes. The existing building and use must be lawful; a later alteration does not automatically cure an unlawful original construction.

The height limits

A building must be single storey, and its eaves must never exceed 2.5 m. Government technical guidance treats a hipped roof under the 4 m dual-pitched limit. The boundary restriction still takes priority.

A pitched shed 1 m from the boundary cannot have a 4 m ridge simply because its eaves are below 2.5 m. In that position, the entire shed must stay within 2.5 m.

Measure height from the ground immediately adjacent to the structure. Where that surface is uneven, the GPDO uses its highest adjacent point. A deck on top of the ground does not become ground level. Eaves are measured where the outside wall, projected upwards if necessary, meets the upper roof surface; gutters and roof overhangs are not the eaves datum.

The 50% coverage calculation

1. Establish the area of the house’s curtilage
2. Subtract the ground area of the original house
3. Take 50% of the remainder
4. Compare this allowance with the combined ground area covered by buildings, enclosures and containers other than the original house

Count existing and proposed extensions and outbuildings together. A detached garage counts even if built at the same time as the original house. Work authorised by a planning application still counts.

For example: 400 m² of curtilage minus a 100 m² original house leaves 300 m². Half is 150 m². If extensions and a garage already occupy 50 m², the remaining allowance under this test is 100 m². The purpose, height and other siting tests may impose much tighter limits.

Original generally means the house as it stood on 1st July 1948, or as first built if later. It does not mean the property as it stood when you bought it.

Where can an outbuilding go?

It must be within the curtilage of the house. Owning land or using it as a garden does not automatically establish that it is within the curtilage. Large grounds, paddocks and land across a road need particular care.

No part of the Class E building, enclosure, pool or container may be on land forward of a wall forming the principal elevation of the original house. That is not always the elevation facing the road. A corner plot, stepped frontage or unusually positioned house needs its elevations identified properly.

Class E does not permit a verandah, balcony or raised platform. For Part 1, a platform is raised if its height is greater than 0.3 m (300 mm). Lower decking must still meet the other relevant Class E requirements.

Conservation areas and other protected land

On all article 2(3) land, no part of the building, enclosure, pool or container may sit on land between a wall forming a side elevation of the house and the curtilage boundary.

Check outriggers and extensions too. E.3 refers to a side wall of the dwellinghouse, not only a side wall of the original main block. A rear projection, including a later extension, can create another side wall and affected side strip. Moving a shed behind the main block does not by itself establish compliance if it remains beside such a projection.

There is a further rule in National Parks, the Broads, National Landscapes (legally designated Areas of Outstanding Natural Beauty) and World Heritage Sites: the combined area covered by buildings, enclosures, pools and containers situated more than 20 m from any wall of the house must not exceed 10 m².

This is a total allowance, not 10 m² for each structure. An existing 5 m² shed in the relevant distant area leaves only 5 m² under that test. E.2 does not apply merely because the land is in a conservation area, although the E.3 side-land restriction does.

When is Class E unavailable?

• Within the curtilage of a listed building
• For a flat, maisonette or building containing flats
• Where permission to use the house as a house arose only through Part 3 Classes G, M, MA, N, P, PA or Q
• For a dwellinghouse built under Part 20
• Where a relevant planning condition or Article 4 direction removes the right

Green Belt designation and local listing do not themselves create the listed-building exclusion in E.1(g). Other applicable restrictions still need checking. For an HMO, establish whether the building is a dwellinghouse for Part 1 purposes rather than assuming its use-class label settles the question. See our Brent dwellinghouse and HMO guide.

Applications and Building Regulations

There is no Class E prior approval procedure. The GPDO grants planning permission where all requirements are met. A certificate of lawfulness for proposed development can formally establish that before construction.

Building Regulations exemptions have separate conditions concerning matters such as size, use, construction and position. Do not confuse a planning allowance with an exemption from Building Regulations. Planning Geek can advise on the planning position and coordinate with appropriate design and building-control specialists.

Related examples

These examples illustrate fact-specific questions rather than creating additional size allowances:

• Luton garage: incidental use and separate access questions
• RSBS: existing unlawful building operations
• Slough: a garden dwelling and proposed gym fallback

Sources and Class E legislation

Checked against the current GPDO Part 1 and article 2 definitions. The government householder technical guidance provides explanations and examples, but must be read with subsequent amendments to the legislation.

Page Updated: 2nd October 2026