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How far can you extend without planning permission?
Choose a rear or side extension, a loft, a porch or a building in the garden, then move the sliders. The drawings change as you go, and so does the answer: permitted development, prior approval, or a planning application.
This shows the national permitted development rules for extensions, loft conversions, porches and garden buildings. Whether your house can use them depends on its permitted development rights still being in place. They can be removed by a condition on an earlier planning permission, an Article 4 direction or the house's history, and this tool can't see any of that.
The only formal confirmation is a lawful development certificate from your council. Please don't rely on this result to build, buy or sell; it's a starting point for a conversation, not planning or legal advice.
Within every limit, so no planning application is needed. A lawful development certificate is still worth having: it proves it to a future buyer.
A guide to the national rules only. Your house's own rights, and a lawful development certificate from the council, decide it.
| Rule | Yours | Limit | Result |
|---|---|---|---|
| How far it comes out | 3 m | 3 m, or 6 m with prior approval | Passes |
| Overall height | 3 m | 4 m | Passes |
| No higher than the house | 3 m | The house's highest roof (7.8 m) | Passes |
| Eaves no higher than the house's | 3 m | The house's eaves (5.4 m) | Passes |
| Eaves height near a boundary | 3 m | 3 m within 2 m of a boundary | Passes |
| Width | 6.5 m | No wider than the house (6.5 m) | Passes |
| Garden built on | 14% | No more than half | Passes |
| Materials Brick to match, or render where the house is rendered. | As chosen | Similar in appearance to the house | Note |
| No balcony or raised platform A balcony, veranda or raised terrace (over 30 cm) needs planning permission of its own. | None | No balcony, veranda or raised platform | Note |
| Garden left behind it | 11 m | No rule for one storey | Note |
Now check your real address
Find out what applies to your house.
The plotwise report by DZP looks up the designations, the planning history and what your neighbours have been allowed, for your actual address. It's in your inbox in as little as 30 minutes during office hours, and always within 24 hours, with a free 30-minute call with a chartered architect to talk it through.
Ready to build? We can apply for the lawful development certificate that confirms it.