Does Your Outbuilding Need Planning Permission?

Many outbuildings qualify as 'permitted development,' meaning you won't need to submit a planning application, provided your project adheres to specific limitations and conditions. It is absolutely vital that every single condition is met for your structure to be considered permitted development.

Outbuildings You Can Build Without Planning Permission

You can typically construct an outbuilding without formal planning approval if it complies with the following criteria:

• The outbuilding must not be positioned in front of the wall that forms the main face of your house (the one that usually looks onto the street).

• It needs to be a single-storey structure.

• The highest point of the eaves (where the roof meets the wall) cannot exceed 2.5 metres.

• Regarding the roof's overall height, it can be up to four metres if it's a dual-pitched roof, or a maximum of three metres for any other style of roof.

• Should any part of your building, enclosure, or container be within two metres of your property's boundary line, its height must not be more than 2.5 metres.

• You cannot include verandas, balconies, or any raised platforms. Any platform you do build must not be taller than 0.3 metres from the ground.

• The total area of land around your "original house" covered by new additions or other buildings must not exceed half.

When we refer to the "original house," we mean the dwelling as it was first built, or as it existed on 1 July 1948 if it was constructed before that date. Please be aware that a previous owner might have extended the house, even if you haven't made any additions yourself.

When You DO Need Planning Permission

You will need to apply for planning permission in the following circumstances:

• Designated Land: If your property is situated on designated land, any outbuildings, enclosures, containers, or pools located to the side of your house will require planning permission. Designated land includes National Parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas, and World Heritage Sites.

• National Parks & AONBs: Within specific areas such as National Parks, the Broads, Areas of Outstanding Natural Beauty, and World Heritage Sites, there's an additional restriction: if your structure (a building, enclosure, container, or pool) is more than 20 metres away from your house, its total footprint cannot exceed 10 square metres.

• Listed Buildings: If your outbuilding is planned within the curtilage (the immediate land surrounding) of a listed building, you must obtain planning permission.

• Other Exclusions: Please note that the 'permitted development' allowances for outbuildings apply exclusively to houses. They do NOT extend to:

  • Flats and maisonettes.

  • Homes that have been converted from other buildings, or houses that were created through specific 'permitted development' rights (specifically Schedule 2, Part 3, Classes G; M; MA; N; P; PA and Q for 'Changes of use'; and Schedule 2, Part 20 for 'New Dwellinghouses').

  • Any other non-residential buildings.

  • Areas where planning conditions, Article 4 Directions, or other local restrictions already limit permitted development rights.

Considerations for Garden Annexes and Separate Living Spaces

If you intend for your outbuilding to be used as a separate, self-contained living area – for example, a garden annexe with its own bedroom, kitchen, and bathroom for independent living – it will typically require planning permission. Such structures are generally NOT considered 'incidental' to the main dwelling (meaning they are not merely secondary uses like a shed or garage) and therefore do not qualify under the standard permitted development rights for outbuildings.

Still Unsure? Seek Expert Advice

If you're uncertain whether your planned structure qualifies as an 'outbuilding' or if you require planning permission, we strongly recommend that you contact your local planning authority for advice. To get a formal decision on whether your proposed work is lawful without needing to submit a full planning application, you can apply to your local authority for a Lawful Development Certificate.

Further Resources on Planning Permission

For a detailed understanding of how these permitted development rules might apply to your specific circumstances, you are strongly advised to read the technical guidance document published by the UK Government. You can access it here: Permitted Development Rights for Householders – Technical Guidance.