Permitted Development: What You Can Build Without Planning Permission

Permitted development rights are one of the most useful — and most misunderstood — parts of the UK planning system. They allow certain categories of building work to go ahead without submitting a full planning application, provided the work stays within specific conditions and limits. The key word is conditional: permitted development is not a blanket "anything goes" allowance, and getting a detail wrong can mean the work was never actually lawful, even if no one objected at the time.

What permitted development actually covers

In general terms, permitted development rights in England typically extend to things like:

• Single-storey rear extensions, up to a size limit that depends on whether the house is detached, semi-detached or terraced
• Loft conversions, up to a volume allowance — 40m³ for terraced houses, 50m³ for semi-detached and detached houses — subject to conditions on materials and roof design
• Certain outbuildings, sheds and garages
• Porches, up to a limited floor area
• Some changes to windows and doors, and some external alterations

Each category has its own specific size limits, height restrictions, and conditions (for example, matching materials to the existing house, or restrictions on how close to a boundary you can build) — this page describes the general shape of the system, not a substitute for checking the current, exact limits for your specific project and property.

A quick sense of scale, before you dig into the detail

• Single-storey rear extension: broadly 3–4m of depth without prior approval (more for a detached house than an attached one), or up to 6–8m via the Larger Home Extension prior approval route — see our dedicated extension permitted development guide for the full breakdown by house type.
• Loft conversion: broadly 40m³ (terraced) or 50m³ (semi-detached/detached) of additional roof volume — see our loft conversion planning guide for what usually qualifies.
• Two-storey rear extension: a smaller, more tightly restricted allowance than single-storey — broadly around 3m of depth, and not permitted within 7m of the rear boundary.

Common misconceptions worth clearing up

• "My neighbour did it, so I can too." Permitted development depends on your specific property's history — a previous owner's extension, a loft conversion, or an outbuilding can all reduce your remaining allowance, even if your neighbour's identical-looking house still has its full allowance intact.
• "It's under the size limit, so it's automatically fine." Size is one condition among several — materials, height, boundary proximity, roof pitch matching and designated-area status all apply independently. Meeting the size limit doesn't override the others.
• "I don't need to tell anyone." Even genuinely permitted development work is worth confirming formally with a Certificate of Lawful Development (see below), and separately, building regulations approval is usually still required even when planning permission isn't.

What can remove or restrict permitted development rights

• Article 4 directions — a local authority can remove specific permitted development rights in a defined area, often in conservation areas, to protect local character.
• Listed buildings — permitted development rights are significantly more restricted, and listed building consent is a separate, additional requirement for most alterations.
• Conservation areas, National Parks and Areas of Outstanding Natural Beauty — permitted development allowances are often reduced compared to a standard residential area.
• Conditions on a previous planning permission — some new-build developments have permitted development rights removed as a condition of the original approval.
• Flats and maisonettes — generally don't carry the same permitted development rights as houses.

What happens if you build without checking first

Building work that turns out not to have genuinely qualified for permitted development doesn't necessarily mean an automatic enforcement notice — but it does mean the work was never formally lawful, which becomes a real, practical problem later: at the point of selling the property, a solicitor or buyer's surveyor will typically ask for proof the work was either granted planning permission or genuinely fell within permitted development. Without that proof, buyers and their lenders can get nervous, sales can be delayed, and in some cases a retrospective planning application (with no guarantee of success) becomes necessary. This is a genuinely avoidable problem — checking first, and getting formal confirmation, is far cheaper and less stressful than untangling it after the work is done.

Two of the most common permitted development questions

Extensions and loft conversions are the two project types homeowners most often ask about specifically — see our dedicated guides on permitted development for extensions and planning permission for loft conversions for the specifics of each.

Get it confirmed formally

Even where you're confident permitted development applies, it's worth applying for a Certificate of Lawful Development from your local planning authority. It doesn't cost as much as a full planning application and gives you a formal record that the work was lawful — genuinely useful when selling the property later, since a solicitor or buyer's surveyor will often ask for exactly this kind of proof.

Planning permission isn't the whole picture

Even when planning permission genuinely isn't needed, building regulations approval usually still is — they're separate systems covering different things. See our guide on building regulations vs planning permission for exactly how they differ, and if your project involves work on or near a shared boundary or wall, check whether you also need to serve notice under the Party Wall Act.

Before you finalise a design: a short checklist

• Confirm your house type (detached, semi-detached, terraced) — it changes your allowance
• Check whether any previous extension, loft conversion or large outbuilding has already used up part of your permitted development allowance
• Check whether you're in a conservation area, National Park, AONB, or subject to an Article 4 direction
• Confirm whether your property is listed
• Get the current, exact size/height limits confirmed for your specific project with your local planning authority
• Apply for a Certificate of Lawful Development once you're confident the work qualifies

The sensible approach

Given how much detail sits behind "permitted development" as a general term, the safest approach for any specific project is: check the current, exact limits that apply to your property type and location with your local planning authority, and get a Certificate of Lawful Development for anything you're relying on permitted development rights for. This page — and the rest of this guide series — gives you the general shape of the system so you know what to ask and what to expect, not a substitute for that confirmation.