Permitted Development Rights in England: A Builder's Guide

What Are Permitted Development Rights?

Permitted development (PD) rights allow homeowners to carry out certain types of building work without needing to apply for planning permission. They're granted automatically under the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended).

Think of them as a set of pre-approved rules. As long as your project falls within the size limits and conditions, you can crack on without going through the planning application process.

But — and this is important — permitted development does not mean you don't need Building Regulations approval. More on that later.

These rules apply to houses in England. Flats, maisonettes, and houses in Scotland, Wales, and Northern Ireland have different rules. If the property is in a conservation area, national park, Area of Outstanding Natural Beauty (AONB), or is a listed building, the rules are significantly more restrictive.

PD Limits at a Glance

Here's a summary table of the main permitted development allowances for householders in England. These are the limits — if your project exceeds any of them, you'll need a full planning application.

| Development Type | Key PD Limits | |-----------------|---------------| | Single-storey rear extension | Detached: max 8m deep (4m if side), Semi/terrace: max 6m deep (3m if side). Max height 4m. Max eaves height 3m. | | Two-storey rear extension | Max 3m deep beyond original rear wall. Must be at least 7m from rear boundary. Max eaves/ridge no higher than existing house. | | Side extension | Single storey only under PD. Max width: half the width of original house. Max height 4m, eaves 3m. Must match materials. | | Loft conversion | Max 40m³ additional volume (terraced/semi) or 50m³ (detached). No extension beyond the existing roof plane facing a highway. Materials must match. | | Outbuilding | Max 50% of garden covered by outbuildings/extensions. Max height 2.5m if within 2m of boundary, otherwise 4m (dual pitch) or 3m (flat roof). Not forward of principal elevation. | | Porch | Max 3m² floor area. Max 3m height. Must be more than 2m from any boundary facing a highway. | | Fences/walls/gates | Max 2m height (1m if adjacent to a highway). No planning needed for like-for-like replacement. | | Hard surfaces | Front garden: must be permeable or drain to a permeable area if over 5m². Rear: no restrictions under PD. |

Note: The "original house" means the house as it was built, or as it stood on 1 July 1948 — whichever is later. Previous extensions count towards your PD allowance.

Use our Permitted Development tool to check whether your specific project falls within these limits.

Single-Storey Rear Extensions in Detail

This is the most common type of PD work, and the rules were relaxed in 2013 under the "larger home extension" scheme (now made permanent).

For a detached house, you can extend up to 8 metres from the original rear wall without planning permission. For a semi-detached or terraced house, the limit is 6 metres.

Key conditions:

• Maximum height of 4 metres
• Eaves height no more than 3 metres
• Single storey only
• Cannot extend beyond the side wall of the original house (on the side facing a highway)
• Materials should be similar in appearance to the existing house
• No verandas, balconies, or raised platforms
• If extending more than 4m (detached) or 3m (semi/terraced), you must go through the prior approval process (also called the neighbour consultation scheme)

Prior Approval vs Full Planning

Prior approval isn't the same as a full planning application. It's a lighter-touch process where the council notifies your neighbours, and if no objections are raised within 21 days, you can proceed. The council can only consider the impact on amenity of adjoining properties — not design, materials, or anything else.

It costs £120 and typically takes 42 days. It's worth doing properly — if you skip it when it's required, the work is technically unauthorised.

Loft Conversions

Most loft conversions fall within permitted development, provided you stay within the volume limits:

• 40 cubic metres of additional roof space for terraced and semi-detached houses
• 50 cubic metres for detached houses

The volume is measured externally and includes any previous roof extensions. Dormers are allowed under PD, but not on the roof plane facing a highway (typically the front). Roof lights (Velux-style windows) are generally fine on any elevation.

Materials must be similar in appearance to the existing house. The conversion cannot increase the overall height of the roof.

What about the Party Wall Act?

If you share a wall with a neighbour (semi or terrace), loft conversion work that affects the party wall will require a Party Wall Notice under the Party Wall etc. Act 1996. This is separate from planning and Building Regs — don't forget it.

Outbuildings, Sheds, and Garden Rooms

You can put up outbuildings — sheds, workshops, garden offices, summerhouses — without planning permission, subject to these rules:

• They must not cover more than 50% of the garden (combined with extensions and other outbuildings)
• They must not be forward of the principal elevation (the front of the house)
• If within 2 metres of a boundary, maximum height is 2.5 metres
• Otherwise, maximum height is 4 metres (dual-pitch roof) or 3 metres (any other roof type)
• No sleeping accommodation (this would make it a separate dwelling and require planning)
• No balconies or verandas

A garden room used as a home office is generally fine. A garden room with a bedroom, bathroom, and kitchenette is likely a change of use and needs planning permission.

Porches

A small porch at any external door is permitted development if:

• The floor area doesn't exceed 3 square metres (external measurements)
• The height doesn't exceed 3 metres
• No part is within 2 metres of a boundary fronting a highway

This is a surprisingly tight allowance. Many "porches" that builders are asked to construct are actually too large for PD and need a planning application.

Conservation Areas, AONBs, and Listed Buildings

If the property is in any of the following designated areas, PD rights are significantly reduced:

• Conservation areas — no side extensions, no rear extensions above one storey, no cladding, tighter rules on outbuildings and roof alterations
• Areas of Outstanding Natural Beauty (AONB) / National Parks / The Broads — similar restrictions to conservation areas
• Listed buildings — virtually no PD rights. Almost any alteration (internal or external) requires Listed Building Consent
• Article 4 directions — local councils can remove specific PD rights in certain areas

Always check the property's designation before assuming PD applies. Our Pre-App Checker can help you work out whether the property has any restrictions that might affect your plans.

When You Still Need Building Regulations

This is where many homeowners (and some builders) get confused. Permitted development only removes the need for planning permission. You almost certainly still need Building Regulations approval for:

• Any extension (single or two-storey)
• Loft conversions
• Structural alterations
• Electrical work in kitchens, bathrooms, and outdoors (Part P)
• New heating installations
• Replacement windows (unless installed by a FENSA-registered company)
• Drainage alterations

Building Regulations cover structural integrity, fire safety, energy efficiency, ventilation, and drainage. They're enforced by your local authority's Building Control team or a registered building control approver. The Planning Portal provides detailed guidance on planning and building regulation requirements.

You can either submit a Full Plans application (recommended for anything substantial) or use a Building Notice (quicker but no upfront approval of your plans).

How to Confirm Your PD Rights

If you want absolute certainty that your project is permitted development, you can apply for a Certificate of Lawful Development (sometimes called a lawful development certificate or LDC). This is a formal confirmation from the council that your proposed work is lawful.

It costs £258 (as of 2026) and typically takes 8 weeks. It's not mandatory, but it's useful if:

• You're close to the PD limits and want certainty
• You plan to sell the property and buyers/solicitors will ask about the extension
• The work has already been done and you need to regularise it

Many conveyancing solicitors now ask for evidence that extensions were either approved through planning or confirmed as PD. Having a certificate avoids delays when selling.

Practical Tips for Builders

If you're a builder advising clients on whether they need planning permission, keep these points in mind:

• Always measure from the original house — not the house as it stands if it's already been extended
• Check for previous extensions — they count towards PD volume and area limits
• Check the property designation — conservation areas and Article 4 directions can catch you out
• Don't confuse PD with Building Regs — one doesn't exempt you from the other
• Recommend an LDC for anything borderline — it's cheaper than an enforcement notice

Our Permitted Development tool lets you input the basic details of a proposed project and quickly see whether it's likely to fall within PD limits. It's a good starting point before you advise your client — though for anything complex, suggest they get a planning consultant involved.

The Bottom Line

Permitted development rights are a genuine time-saver for straightforward domestic projects. But the limits are specific, the conditions are detailed, and getting it wrong can mean enforcement action, demolition notices, or problems when the client tries to sell.

Know the rules, check the designations, and when in doubt, apply for a certificate. It's always cheaper to check first than to fix it afterwards.