The maximum shed size you can build without planning permission in England is not set by one national floor-area limit. It depends on the 50% coverage allowance, the shed's height, its position in the garden and how you use it.
This article reflects the rules checked on ****. The rules below apply to a typical house, not a flat or maisonette. Wales, Scotland and Northern Ireland have different planning rules.
Shed Size Limits Without Planning Permission
| Requirement | Maximum allowed under permitted development |
|---|---|
| Overall footprint | No fixed national square-metre limit, but buildings and extensions must not cover more than 50% of the land around the original house |
| Number of storeys | One storey |
| Overall height with a dual-pitched roof | 4 metres |
| Overall height with any other roof | 3 metres |
| Overall height within 2 metres of a boundary | 2.5 metres |
| Maximum eaves height | 2.5 metres |
| Use | Storage, workshop, gym, home office or another use incidental to the house |
| Separate accommodation | Not allowed under permitted development |
Height is measured from the highest ground level immediately next to the shed to its highest point. If any part of the shed is within 2 metres of the boundary, the whole shed must be no more than 2.5 metres high, including the roof.
How Does the 50% Shed Rule Work?
The 50% rule applies to the land around the original house. It does not mean that the shed can cover half of the entire property.
The calculation excludes the ground area occupied by the original house itself. It includes relevant existing and proposed buildings, outbuildings and extensions.
For example:
- Land around the original house: 120 square metres
- Maximum permitted coverage: 60 square metres
- Existing extension and garage: 25 square metres
- Remaining allowance for a new shed: 35 square metres
A shed measuring 5 metres by 7 metres would have a 35-square-metre footprint. It could fit within that example's remaining allowance if it also meets the height, position and use requirements.
The calculation uses the shed's ground footprint, not its internal usable floor area.
Where Can the Shed Be Positioned?
A shed cannot be built on land forward of the principal elevation of the original house. In most cases, this means it cannot be placed in front of the main front wall under permitted development rights.
The shed must also be detached from the house if you are relying on the outbuilding rules under Class E. An attached structure may be treated as an extension instead, which means different permitted development rules would apply.
What Can the Shed Be Used For?
The shed must be used for a purpose incidental to the enjoyment of the house. Examples include:
- Garden and tool storage
- A workshop
- A home office
- A gym
- A hobby room
- A playroom
- Storage for bicycles or household equipment
A shed cannot normally be used as a separate self-contained home. A bedroom, bathroom or kitchen arrangement that creates independent living accommodation falls outside the permitted development rules for ordinary outbuildings.
When Does a Shed Need Planning Permission?
You are likely to need planning permission if the shed:
- Has more than one storey
- Exceeds the relevant height limits
- Has eaves higher than 2.5 metres
- Is within 2 metres of a boundary and exceeds 2.5 metres overall
- Sits forward of the principal elevation
- Causes buildings and extensions to exceed the 50% coverage limit
- Provides separate living accommodation
- Is built within the grounds of a listed building
- Is positioned between a side wall of the house and the boundary in a conservation area, National Park, Area of Outstanding Natural Beauty, the Broads or a World Heritage Site
- Is more than 20 metres from the house in a protected area and the relevant outbuildings exceed 10 square metres in total
- Is affected by an Article 4 Direction or planning conditions that remove permitted development rights
For a listed building, the government guidance states that planning permission is required for an outbuilding within the building's curtilage. Protected areas also have additional restrictions on the position and size of outbuildings.
Do Building Regulations Apply to a Shed?
Planning permission and building regulations are separate requirements.
In England, building regulations will not normally apply to a detached shed that:
- Has a floor area below 15 square metres
- Contains no sleeping accommodation
For a detached outbuilding between 15 and 30 square metres, building regulations will not normally apply if it contains no sleeping accommodation and it is either at least 1 metre from the boundary or built substantially from non-combustible materials.
A larger shed, insulated garden room or building containing sleeping accommodation may need building regulations approval even when planning permission is not required.
How Can You Confirm That Your Shed Is Lawful?
If the design is close to the limits, apply to your local planning authority for a Lawful Development Certificate for a proposed development before starting work.
The certificate confirms whether the proposed shed would be lawful under planning legislation. It does not replace building regulations approval or listed building consent where those are required.
The practical answer is simple: calculate the remaining 50% coverage allowance, then check the shed's height, position and intended use against the permitted development rules. If any part of the design falls outside those limits, speak to your local planning authority before building.