If you are looking to add to your garden whether you are thinking about building a summerhouse or an outbuilding it is important to know what you need with regards to planning permission. If you’re asking yourself “can I build a house in my garden?” Read on.

Choosing the Right Fixture

What do you want to build? This is the key component of determining whether you need planning permission or not. The UK government stipulates that a building or enclosure built within a property boundary is a Class E building, which doesn’t require planning permission. If this and other existing buildings do not cover any more than 50% of what is called the total “curtilage” of the house, it doesn’t require planning permission.

You’ll Need Planning Permission If:

• Your garden building will be more than one storey or have eaves higher than 2.5 metres.
• The overall height will be more than 4 metres for a dual-pitched roof.
• The overall height will be more than 3 metres for other roof types.
• The overall height will be more than 2.5 metres if the building is within 2 metres of the boundary of the curtilage of your home.
• The total building (or buildings) will take up more than 50% of all land outside the house. For example, if you wanted to add a shed, which would take up 20% but there is already a building taking up 31%, you would need planning permission as they take up 51% of the land.
• You want a balcony, veranda, or raised platform as part of the building.
• You plan to use the building as sleeping accommodation.
• The building impacts your neighbours’ right to privacy, and this includes treehouses.
• If your residence is classed as a listed building.

You Won’t Need Planning Permission If:

• You are building a shed or summer house that doesn’t extend further than the dimensions above. 
• Your building is a Class E, which is classed as: 

1. A) any building or enclosure, swimming or other pool required for a purpose incidental to the enjoyment of the dwellinghouse as such, or the maintenance, improvement or other alteration of such a building or enclosure; or
2. B) a container used for domestic heating purposes for the storage of oil or liquid petroleum gas.

(Source: https://ecab.planningportal.co.uk/uploads/miniguides/outbuildings/outbuildings.pdf) 

As most sheds, cabins, and summer houses are Class E buildings, they will not need planning permission. 

• If you are going to make your outdoor building a space for socialising or intend to work there, you will not need planning permission (unless they fall under the dimensions listed above).

Additionally, according to the UK government, there are building projects which do not need planning permission, known as “permitted development rights,” and include:

• Industrial premises and warehouses, although there are some limits.
• Some outdoor signs and advertisements.
• Demolition, but approval from your local planning authority is required to demolish.

In conclusion, as you can see there are a variety of stipulations that will determine if you have to get planning permission or not.