Rear extensions in a conservation area: do you need planning permission?
You can still build a single-storey rear extension in a conservation area without planning permission, within the standard limits: 3m from the back of a semi or terrace, 4m for a detached house, and no more than 4m tall. What you lose is the larger home extension scheme, two-storey extensions and some cladding materials.
Conservation areas are designated by councils to protect the character of historic neighbourhoods, so the government removes the permitted development rights most likely to change how a street looks. Rear extensions are usually out of public view, so the basic right stays. The extras that allow bigger or more visible extensions don't.
Two things often catch people out in conservation areas:
- Article 4 directions. Many councils add an Article 4 direction to a conservation area, and some remove the rear extension right altogether. Check the council's conservation area page or ask its planning team.
- Trees. Trees in a conservation area are protected even without a tree preservation order: you must give the council six weeks' notice before cutting down or pruning most of them, which matters if the extension's foundations are near a tree.
If your plans go beyond the standard limits, you'll need a householder planning application. Councils in conservation areas look closely at materials and design, so many offer pre-application advice, which is worth using before you commission full drawings.
What changes in a conservation area?
These are the rules that apply only in a conservation area. Everything in the standard limits for rear extensions still applies as well.
- Extensions of more than one storey aren't permitted development in a conservation area, National Landscape, national park or World Heritage Site. Class A.2(c)
- In this location a single-storey rear extension to a detached house is limited to 4m. The larger 8m allowance doesn't apply in conservation areas, National Landscapes, national parks, World Heritage Sites or SSSIs. Class A.1(f) and (g)
- In this location a single-storey rear extension to a semi-detached or terraced house is limited to 3m. The larger 6m allowance doesn't apply in conservation areas, National Landscapes, national parks, World Heritage Sites or SSSIs. Class A.1(f) and (g)
- In a conservation area you must give the council six weeks' notice before cutting down or pruning most trees, even ones without a tree preservation order.
Not sure whether your home is in a conservation area? Find your council to see the protected areas and Article 4 directions it has published, or start a check to look up your exact address.
Check your own address: put a pin on your house and we'll look up the conservation areas, listed buildings, Article 4 directions and other designations there.
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