Permitted Development Rights Explained: What You Can Build Without Planning Permission

Permitted development (PD) rights allow homeowners in England to carry out certain building works without needing planning permission. For extensions, this is incredibly valuable — it saves money, time, and the uncertainty of a planning decision. But the rules are specific, and getting them wrong is costly. Here's a plain-English breakdown.

The Key PD Rules for House Extensions (England, 2025)

Single Storey Rear Extensions

• Detached houses: up to 4 metres beyond the original rear wall
• Semi-detached and terraced: up to 3 metres beyond the original rear wall
• Maximum eaves height: 3 metres
• Maximum overall height: 4 metres
• Must not be higher than the existing roof ridge

Larger Home Extension Scheme

Under this scheme, detached houses can extend up to 8 metres and other houses up to 6 metres without full planning permission, subject to a prior approval process (neighbour consultation). This scheme was made permanent in 2020.

Double Storey Rear Extensions

• Maximum depth: 3 metres beyond the original rear wall
• Must be at least 7 metres from the rear boundary
• Maximum eaves height: same as the existing house
• Maximum height: same as the existing house
• No balconies or raised platforms

Side Extensions

• Maximum width: half the width of the original house
• Single storey only (unless granted planning permission)
• No side extensions on designated land (conservation areas)

When PD Rights Don't Apply

Your permitted development rights may be restricted or removed if:

• Your property is in a conservation area, AONB, or National Park
• The property is a listed building
• Your council has issued an Article 4 Direction removing PD rights
• You live in a flat, maisonette, or converted house
• A planning condition was attached to your property's original permission

Prior Approval vs Planning Permission vs Building Regulations

Route	When Needed	Timescale	Cost
PD (no application)	Extension within PD limits	None	£0
Prior Approval	Larger Home Extension Scheme	42 days	£120
Full Planning Permission	Outside PD limits	8 weeks	£206
Building Regulations	All extensions always	Ongoing	£500–£1,000

Lawful Development Certificate — Always Get One

Even if you're working under PD rights, apply to your council for a Lawful Development Certificate (LDC). This costs around £103 and provides legal proof that the works were lawful at the time. When you sell your home, solicitors will ask whether the extension had permission — an LDC answers that question definitively. It's a small cost that prevents significant problems later.

Common Myths About Permitted Development

• Myth: "My extension is under 4m so it's definitely PD." — Not necessarily. You also need to check boundary distances, material matching rules, and that you haven't already used your PD allowance.
• Myth: "I don't need building regulations if I have PD rights." — False. Building regulations are always required for extensions, regardless of planning status.
• Myth: "My neighbour can't stop a PD extension." — Mostly true, but if you're using the Larger Home Extension Scheme, neighbours can object and trigger a prior approval assessment.