What Is Permitted Development? — Planning Rights Explained
A plain-English guide to permitted development rights in England: what you can build without planning permission, size limits, and conditions.
Definition
Permitted development (PD) refers to certain types of building work and changes of use that can be carried out without needing to apply for planning permission. These rights are granted by the Town and Country Planning (General Permitted Development) (England) Order 2015 (GPDO) and allow homeowners and developers to carry out specified work provided they meet detailed conditions and limitations set out in the Order.
When Is It Used?
PD rights are used by homeowners for extensions, outbuildings, loft conversions, and other improvements without the time and cost of a planning application. They are also used for changes of use (e.g., office to residential under Class O/MA), agricultural to residential conversions (Class Q), and commercial development. A Lawful Development Certificate (LDC) can be obtained from the local authority to confirm that proposed work falls within PD rights.
Key Facts
- Single-storey rear extension: max 4 m depth (detached) or 3 m (other), max 4 m height
- Larger home extension (prior approval): up to 8 m (detached) or 6 m (other) single-storey rear
- Side extension: max half the width of the original house, single storey only
- Outbuildings: max 50% of garden area, max 2.5 m eaves height, max 4 m ridge (dual pitch) or 3 m (flat roof)
- Loft conversion: max 40 m³ (terraced) or 50 m³ (detached/semi) additional roof space
- No PD rights for listed buildings (external works), most flats, or land in Article 4 areas
- Materials should be similar in appearance to the existing house
- No part of the extension may be higher than the existing roof ridge line
Related Calculators
Use the Extension Cost Calculator to estimate project costs, or the Foundation Calculator for extension groundworks. The Roof Area Calculator helps with loft conversion volume calculations.
How We Calculate This
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Verify with your supplier.