Many London homeowners assume they need full planning permission for any building work. In reality, a significant number of projects — including many extensions and loft conversions — can proceed under Permitted Development (PD) rights.
What Is Permitted Development?
PD rights allow certain types of building work without a formal planning application. The government sets size limits, height restrictions, and conditions that your project must meet.
Key PD Limits for Extensions
- Single-storey rear extensions: up to 6m (semi/terraced) or 8m (detached) under Prior Approval
- Maximum eaves height of 3m within 2m of a boundary
- No more than half the original garden covered by additions
- Materials to match the existing house in appearance
When You Need Full Planning
- Your property is in a conservation area, AONB, or is listed
- You've already used up your PD allowance with previous extensions
- The project exceeds PD size limits
- You're building a separate dwelling or changing the use of the building
Regardless of the planning route, Building Regulations approval — and therefore structural engineering input — is always required for extensions.
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