Key Takeaways
- Permitted Development (PD) lets you build within set limits without a full planning application.
- Common PD projects include rear extensions, loft dormers, outbuildings and porches, within strict size rules.
- PD is not the same as Building Regulations, which still apply.
- Flats and maisonettes do not have the same PD rights as houses.
- Article 4 directions and conservation areas can remove PD rights in parts of London.
Permitted Development rights are one of the most useful tools for London homeowners, letting you extend or convert without a full planning application. But the rules are precise, and they do not apply everywhere. Here is what you can and cannot do in 2026.
What is Permitted Development?
Permitted Development (PD) is a set of national rights that allow certain works without a full planning application, as long as they stay within defined limits. It exists to let homeowners make reasonable improvements without burdening the planning system. Crucially, PD is separate from Building Regulations, which still apply to the structure, insulation, drainage and safety of the work.
What you can build under PD
- Single-storey rear extensions within set depth and height limits.
- Rear dormer loft conversions within volume limits.
- Outbuildings such as garden offices, within size and siting rules.
- Porches, roof works and some window changes, subject to conditions.
There are conditions on height, materials matching the existing house, and how much garden can be covered. Side extensions and double-storey work are more restricted.
Where PD does not apply
PD rights are removed or restricted in several common London situations:
- Flats and maisonettes do not have the same PD rights as houses.
- Conservation areas have tighter limits.
- Listed buildings need consent for most changes.
- Article 4 directions can remove PD rights for a specific area or street.
Get certainty with a Lawful Development Certificate
Even when your project is permitted, it is wise to apply for a Lawful Development Certificate, which formally confirms the work is lawful. It gives you certainty before you build and is valuable proof for buyers and solicitors later. We confirm your property's PD position and handle certificates as part of the project. For advice, contact us or call 07472 424 226. See also how to get planning permission.