1. Permitted Development Rights

No Planning Permission Required: Under UK permitted development rights, you can build a garden house without planning permission, provided certain conditions are met:
Size: The garden house must not exceed 50% of the total area of land around the original house (this includes any other buildings and extensions).
Height: The maximum height is 2.5 meters for a structure within 2 meters of a boundary, and 4 meters for a dual-pitched roof (3 meters for other roofs).
Location: The garden house must not be in front of the principal elevation of the house (it should be in the back garden).
Usage: The garden house must be used for purposes incidental to the main dwelling, such as a home office, gym, or storage. It should not be used as a separate residence.
Designated Areas: In designated areas (like national parks, Areas of Outstanding Natural Beauty, or conservation areas), additional restrictions apply, and planning permission may be required.

2. When Planning Permission is Required

Large Structures: If the garden house exceeds the size and height limits mentioned above, planning permission will be necessary.
Separate Living Accommodation: If you intend to use the garden house as a separate living space (e.g., a granny flat or guest accommodation), planning permission is required, as this changes the use of the building.
Listed Buildings: If your property is a listed building, you will need both planning permission and listed building consent, regardless of the size and location of the garden house.
Designated Areas: As mentioned, stricter rules apply in conservation areas, national parks, and similar locations, which may require planning permission.

3. Building Regulations

Compliance: Even if planning permission is not required, you must comply with building regulations, particularly if the garden house includes plumbing, electrical installations, or is used as sleeping accommodation.
Insulation and Safety: If the garden house is habitable, it must meet regulations for insulation, structural safety, and fire safety.


In the UK, building a garden house, granny flat, or guest accommodation typically requires some form of permission, depending on the size, location, and intended use of the structure. Here’s a breakdown of what you need to consider:


1. Permitted Development Rights

General Overview: Under Permitted Development Rights, certain small-scale structures can be built without the need for full planning permission. However, these rights have limits and conditions.
Criteria for Garden Buildings: To qualify under Permitted Development:
Size: The building should not exceed a maximum height of 2.5 meters if within 2 meters of the boundary, or 4 meters for a dual-pitched roof.
Floor Area: The floor area should not cover more than 50% of the garden area.
Use: The building must be used for purposes that are incidental to the main dwelling, such as a home office, gym, or storage. Using it as a self-contained living accommodation (granny flat or guest accommodation) generally does not fall under Permitted Development.
Location: The building must be located in the rear garden and not extend forward of the principal elevation of the house.


2. Planning Permission

When Required: If the garden building is intended as a granny flat, guest accommodation, or another type of self-contained living space, planning permission is usually required. This is because such a use involves creating a separate dwelling, even if it is on the same property.
Application Process: You will need to submit an application to your local planning authority, including detailed plans and descriptions of the intended use. Factors that will be considered include the impact on neighbors, the design and appearance of the building, and compliance with local planning policies.


It typically takes 4 to 8 weeks

to get a response to a pre-application. It's important to bear in mind a pre-application does not grant any approval or pre-approval. It will simply be a written response to advise whether planning permission is likely to be required, what would be required to support a planning application, and an indication of whether in principle it is likely to be approved or not.
The cost of a pre-application varies depending on the project type, size and local authority fees. For smaller schemes such as residential developments, the cost is up to £600.