What is Permitted Development? A Homeowner's Guide
Title: What is Permitted Development? A Homeowner's Guide to What You Can Build Without Planning Permission Target keyword: permitted development rights extensions loft conversion
Permitted development (PD) is one of the most useful — and most misunderstood — concepts in UK planning. Put simply, it's a category of building work that has pre-granted permission from the government, meaning you don't need to apply to your local council for planning approval before starting.
But PD rights come with conditions, limits, and important exceptions. Understanding them is essential before you start any project.
What is Permitted Development?
Permitted development rights are set out in the Town and Country Planning (General Permitted Development) (England) Order 2015, as amended. They define specific categories of work that are automatically permitted — provided the work stays within defined size limits and conditions.
In practice, this means many homeowners can extend their property, convert their loft, or add a garden outbuilding without going through a full planning application. This saves time (no 8-week planning determination period) and cost (no planning fees, architect's planning drawings, or risk of refusal).
What Can You Do Under Permitted Development?
Rear extensions: A single-storey rear extension of up to 4m depth (detached houses) or 3m depth (semi-detached and terraced) is permitted development. The 2019 Prior Approval process extended this to 8m for detached and 6m for other houses, subject to neighbour consultation.
Side extensions: A side extension is PD if it is no more than half the width of the original house, does not exceed the original roof height, and is not forward of the principal elevation.
Loft conversions: Loft conversions are permitted development if they don't increase the original roof volume by more than 50m³ (terraced houses) or 40m³ (detached and semi-detached). Dormers to the rear are generally permitted; front-facing dormers typically are not.
Outbuildings: Garden structures, garages, sheds, and outbuildings are PD within limits — they must be in the rear garden, no more than 4m high (dual pitch) or 3m (flat/mono-pitch), and must not cover more than 50% of the garden.
Porches: A front porch is PD if the floor area doesn't exceed 3m² and the height doesn't exceed 3m above ground level.
What Removes Permitted Development Rights?
Several situations can remove or restrict PD rights:
Conservation areas: Properties in designated conservation areas have reduced PD rights. Cladding, roofing changes, and some extension types require full planning consent.
Article 4 Directions: Local authorities can issue an Article 4 Direction to remove PD rights in specific areas. This is common in parts of inner London. Many terraced streets in Camden, Islington, Hackney, Southwark, and similar boroughs are affected.
Listed buildings: Listed buildings have no PD rights. Every material change — inside or out — requires listed building consent.
Previous extensions: PD is assessed against the original footprint of the house (as built or as it was on 1 July 1948). Previous extensions built by past owners count toward the limits.
Flats and maisonettes: PD rights for extensions do not apply to flats or maisonettes at all.
Do You Still Need Building Regulations?
Yes. Even where planning permission isn't required, Building Regulations approval almost always is. Building Regulations govern the structural, fire, drainage, insulation, ventilation, and electrical standards of the work. This is entirely separate from planning.
For most projects, you'll need either a full plans application (submitted before work starts) or a building notice (can be submitted just before or at the start of work). We typically recommend full plans for any structural work, as it gives you approved drawings to build from and reduces the risk of non-compliant work being identified by the inspector on site.
Check Before You Build
The prudent approach is to check PD eligibility before starting any work, even if you're confident the project is permitted. A Lawful Development Certificate (LDC) from the local authority confirms in writing that your project is lawful — providing protection if you sell the property or if the council ever disputes the position.
At RCB Design & Build, we advise on PD eligibility as part of our pre-construction process. If your project is on the borderline, we'll tell you honestly — and if planning permission is needed, we can coordinate the application.
Call 07359 872594 or visit rcbgroup.co.uk to discuss your project.