TradeCalculator.co.uk
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 Loft PD Volume Calculator checks loft conversions against the 40 and 50 cubic metre permitted development volume limits.
Next up: related pages
How We Calculate This
Frequently Asked Questions
Under PD rights for householders (Part 1 of the GPDO), you can build single-storey rear extensions (up to 4m for detached or 3m for other houses, or up to 8m/6m under prior approval), two-storey rear extensions up to 3m, side extensions up to half the width of the original house, outbuildings covering up to 50% of the garden, loft conversions adding up to 40-50 m³, porches up to 3 m², and various other works subject to specific conditions.
No. PD rights under Part 1 (householder development) apply to houses only, not flats or maisonettes. However, the government introduced new PD rights in 2020 allowing upward extensions to create new flats on top of existing residential blocks (Part 20 of the GPDO), subject to prior approval. Some Class E to C (commercial to residential) conversions also benefit from PD rights.
Permitted development is a national grant of planning permission given by the GPDO (General Permitted Development Order), meaning the permission already exists by law if you meet the conditions. Full planning permission requires a formal application to the local planning authority, consultation with neighbours, and a decision by a planning officer or committee. PD rights can be removed by Article 4 directions or planning conditions.
Yes. Permitted development only covers planning permission. You still need Building Regulations approval for all structural work, electrical work (Part P), drainage, and any work affecting fire safety. For example, a single-storey extension under PD still needs full Building Regulations approval covering foundations, structure, insulation (Part L), ventilation (Part F), and drainage (Part H).
Yes, in several ways. The local authority can issue an Article 4 direction removing specific PD rights in a particular area (common in conservation areas and areas of outstanding natural beauty). PD rights may also have been removed by a condition on the original planning permission for the house. Listed buildings do not have PD rights for any work that would affect the building's character. Always check with your local planning authority before assuming PD rights apply.
Was this calculator helpful?
Last updated: March 2026
Verified against UK standards · estimates only, confirm with your supplier.