Permitted Development Rights UK: What Can You Build Without Planning Permission? [2026]

What Are Permitted Development Rights?

Permitted development (PD) rights are a national grant of planning permission set by central government. They allow certain building works and changes of use to be carried out without submitting a full planning application to your local council. The principal piece of legislation governing these rights for householders in England is the Town and Country Planning (General Permitted Development) (England) Order 2015 (GPDO 2015), which has been amended several times since — most notably to introduce the Larger Home Extension Scheme.

Permitted development rights apply to the original house as it stood on 1 July 1948, or as it was built if constructed after that date. Any previous extensions, outbuildings, or additions already count against the allowances available to you. If a previous owner has already used some of the PD budget, your remaining entitlement is reduced accordingly.

Even when works fall within permitted development, you may still need to comply with Building Regulations — for example, all extensions, loft conversions, and structural changes require Building Regulations approval regardless of whether planning permission is needed. You may also wish to apply for a Lawful Development Certificate (LDC) from your local council, which provides formal written confirmation that works are lawful. An LDC is not legally required, but is highly recommended as evidence for future buyers, mortgage lenders, and insurers.

Rear Extensions (Class A) — Size Limits at a Glance

Rear extensions are the most common use of permitted development. Under Class A of Schedule 2 to the GPDO 2015, single-storey rear extensions are permitted subject to the limits below.

The Larger Home Extension Scheme (sometimes called the prior approval process or the neighbour consultation scheme) allows single-storey rear extensions beyond the standard limits up to the maximums shown above. The process requires you to notify your local planning authority and all adjoining owners and occupiers. Neighbours have 21 days to raise objections. The LPA then assesses whether the extension would have an unacceptable impact on the amenity of adjoining properties and issues a prior approval decision. If no objections are raised and the LPA is satisfied, you can proceed.

Two-storey rear extensions are also permitted under Class A but have tighter restrictions: the extension cannot be closer than 7m to the rear boundary and must not exceed the height of the existing roof. Windows on upper-floor rear extensions must be obscure glazed and non-opening below 1.7m if they face within 45 degrees of the boundary of an adjoining property.

Side Extensions

Side extensions are permitted under Class A but face notably stricter limits than rear extensions. The key rules are:

• Maximum width: half the width of the original house (measured externally)
• Single storey only — maximum height 4m
• Cannot be forward of the principal elevation of the dwelling
• Not permitted in AONBs, National Parks, or the Broads

The half-width rule is frequently misunderstood. "Original house" means the house as first built (or as it stood on 1 July 1948), not as it appears today. If a previous owner added a side extension, that width is already spent — you cannot build a further side extension without planning permission.

Outbuildings, Sheds, and Garden Rooms (Class E)

Outbuildings — including sheds, garden offices, garages, swimming pools, and greenhouses — are governed by Class E. The rules depend on how close the structure is to the boundary:

Additional rules that apply to all outbuildings:

• Cannot cover more than 50% of the total garden area (including the original house footprint for purposes of calculation — note: the 50% applies to land around the house, not including the house itself)
• Must be within the curtilage of the dwelling (your garden, not adjoining land)
• Cannot be placed forward of the principal elevation
• Cannot be used as separate living accommodation (e.g., a self-contained annexe with sleeping and kitchen facilities would require planning permission)
• Must not have a veranda, balcony, or raised platform above 300mm in height

Loft Conversions (Class B)

Converting your loft is one of the most popular ways to add space to a home, and it is generally permitted development for most houses. The key limits under Class B are:

Design conditions that must be met:

• No extension beyond the existing roof slope on the principal elevation — rear dormers are generally fine, front dormers are not
• No extension higher than the highest part of the existing roof
• Side-facing windows must be obscure glazed and fixed shut below 1.7m from the finished floor level
• The materials used in any exterior works must be of a similar appearance to those of the existing house

Note that flats and maisonettes do not benefit from Class B permitted development. If you live in a flat, you will need planning permission for any loft conversion.

Porches (Class D)

Adding a porch to the entrance of your home is permitted development under Class D, provided:

• The ground floor area does not exceed 3m² (measured externally)
• The maximum height does not exceed 3m
• No part of the porch is within 2m of any boundary with a highway

These restrictions apply regardless of whether the property is detached, semi-detached, or terraced. Even small porches require Building Regulations approval for structural work, so always check with a structural engineer or your local building control office.

What Removes or Restricts Permitted Development Rights?

A significant number of properties in England do not benefit from full permitted development rights. Before carrying out any work, you must check whether any of the following apply to your property:

Common Mistakes and Key Pitfalls

Step-by-Step: How to Check If Your Works Are Permitted Development

1. 1

   Establish the original house size

   Find out how large the property was as originally built (or as it stood on 1 July 1948). Check historical maps, the Land Registry, or planning records. This is your starting point for all measurements.

2. 2

   Check for restrictions on the property

   Look up whether your property is listed, in a conservation area, subject to an Article 4 Direction, or in a National Park or AONB. Use your council's planning portal and the Historic England search tool.

3. 3

   Review the planning conditions on your title

   Order the title register from the Land Registry and check the original planning permission for your property or estate. Look for conditions that restrict or remove permitted development rights.

4. 4

   Measure your proposed works against the PD limits

   Compare your extension plans against the relevant Class A, B, D, or E limits. Pay particular attention to depth, height, and the 50% garden coverage rule for outbuildings.

5. 5

   Submit a prior approval application if using the Larger Home Extension Scheme

   If your extension exceeds the standard PD depth limits but falls within the larger scheme, submit a prior approval application to your LPA. Allow at least 42 days for the decision.

6. 6

   Apply for a Lawful Development Certificate

   Once you are confident the works fall within permitted development, consider applying for a Lawful Development Certificate. Your LPA has eight weeks to decide. The fee is currently around £206 for England.

7. 7

   Obtain Building Regulations approval

   Submit a Building Regulations application (either full plans or building notice route) to your local building control office or an approved inspector before construction begins.

Frequently Asked Questions

Related Guides

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• House Extensions in Birmingham: Costs, Rules, and Finding a Builder
• Loft Conversion Cost UK: Prices, Types, and What to Expect in 2026