How many meters can I extend my house without planning permission?

Want to know how big an extension you can build without getting planning permission? It may be more than you think. There are plenty of rules and regulations regarding how big extensions can be, whether they need planning permission or not and where they’re allowed to be built in your home.

In this article, we will explore the main sizes to be aware of when extending your house without planning permission. 

Be aware that - even if you do not need planning permission - extending your house will likely still need building regulations compliance. More on that later. 

Photo Credit @Scott Webb

House Extension garden

Does my house have permitted development?

In order to find out if you can extend your house at all without planning permission. You will need to know if you house has permitted development rights first. Permitted development allows you to extend your house without planning permission.

Typically, most housing in the UK will have permitted development rights including:

- Victorian houses.
- Terraced houses.
- Townhouses.
- Suburban Houses.
- Mews Houses.

If your house is historical, in the countryside or part of a larger development, we recommend checking with your local council if you have any permitted development rights. 

Photo Credit @Jonathan Farber

Does my house have permitted development

How many meters can I extend my house under permitted development?

Now that you know you have permitted development rights on your house. Here are the sizes you can extend your house with planning permission. 

Rear House Extension
3 metre depth x 4 metre height x width of your house.

Side House Extension
3 metre depth x 4 metre height x half width of your original house

Dormer Roof Extension
40 cubic metres for terraced houses.
50 cubic metres for detached and semi-detached houses.

Each extension must only be a single storey. 

Photo Credit @Pedro Miranda

House Extension without planning permission size

House extensions larger than permitted development: what do to

If your house extension plans are larger than the permitted development thresholds. You will need to apply for planning permission so that your house extension is acceptable.

While planning permission can be complex, our professional service can provide you with everything from start to finish. As expert Architects with years of planning knowledge, we ensure you have the best chance possible in gaining planning permission.

Image Credit @Alberto Castillo Q 

House Extension Permitted Development

Other things to know when extending a house

With planning permission covered, you also need to be aware of the need for building regulations compliance when extending your house.

This will mean having detailed construction plans of your house extension, as well as key information, specifications and reports.

Our service includes for managing the requirement for building regulations including drafting construction plans and project managing other consultants. 

Image Credit @Josh Hemsley

Extending House Interior


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