Planning permission — when your extension needs full consent.
Most UK extensions can be built under Permitted Development without applying for planning permission — but conservation areas, Article 4 directions, listed buildings and PD size limits routinely catch homeowners out. The cost of getting it wrong is enforcement and removal. Always commission a Lawful Development Certificate before relying on PD.
Do I need planning permission for an extension?
You may not — single-storey rear extensions up to 4 m (semi-detached) or 6 m (detached) deep, and side extensions up to half the original house width, are typically Permitted Development under Class A of the GPDO 2015. But Article 4 directions, conservation areas, listed buildings, AONBs, and houses already extended remove some or all of those rights. Always check with the council and / or commission a Lawful Development Certificate.
Householder application decision time. 13 weeks for major schemes.
Single-storey: 4 m semi-detached / 6 m detached. Larger via Prior Approval.
Standard 2026 fee for a householder planning application in England.
Planning Permission — the terms that matter
Plain-English definitions for the 6 terms you'll see in any quote, certificate or enforcement notice for Planning Permission for Extensions.
- General Permitted Development Order 2015GPDO 2015
- The statutory instrument granting permission for specified development without need for a planning application. Last major refresh in 2015 with rolling amendments.
- Article 4 DirectionA4D
- A formal notice issued by an LPA removing specified Permitted Development rights within a designated area — common in conservation areas and city-centre HMO restraint zones.
- Lawful Development CertificateLDC
- A formal LPA certificate confirming that proposed (or existing) works fall within Permitted Development. Recommended before relying on PD.
- Householder ApplicationHHA
- A planning application by an owner-occupier for works within the curtilage of their house. £258 fee. 8-week decision window. Most common application type.
- Larger Home Extension NotificationLHE / Prior Approval
- An expedited route under Class A.1(g) for single-storey rear extensions over 4 m / 6 m. Goes via prior approval rather than full planning.
- Local PlanLP
- The LPA's adopted planning policy document. Sets the criteria the case officer applies when deciding your application — design, scale, conservation, daylight / sunlight.
How to apply for planning permission for an extension
Five steps from instruction to certificate. Total time: 10w.
01
Check PD first
Day 0–7
Run a permitted-development check. If your works fall within Class A and there's no Article 4 / conservation area trap, commission a Lawful Development Certificate (£580 fee + drawings) instead of full planning.
02
Drawings
Week 1–3
Architectural technologist or architect produces existing + proposed plans, elevations, sections, site plan, design and access statement (when required).
03
Submit + validate
Week 3–4
Upload to the Planning Portal (or council's direct portal). Pay £258 fee. Wait for validation (1–2 weeks); LPA will request missing items.
04
Statutory consultation
Week 4–7
LPA consults neighbours, statutory consultees, and (where needed) ward councillors / parish councils. 21-day consultation period.
05
Decision
Week 8
Case officer issues approve / refuse / approve-with-conditions decision letter. Permission, once granted, is valid for 3 years to start works.
Planning Permission for Extensions. Done compliant.
Every TradeMatch-listed tradesperson covering Planning Permission for Extensions carries the relevant scheme registration. Verified at onboarding, re-verified annually, certificates posted to you within 30 days of any notifiable work.
Permitted Development vs Full Planning vs Prior Approval
Side-by-side comparison of the compliant route versus the unregistered shortcut. Most rows trace a straight line from regulation to financial exposure.
| Route | When it applies | Fee | Timeline |
|---|---|---|---|
| COMPLIANT — RECOMMENDEDLawful Development Certificate | Works clearly within PD; documented evidence wanted (sale-time, mortgage) | £580 LPA + £950 drawings | 8 weeks LDC decision |
| Householder full planning | Works exceed PD limits; or Article 4 / conservation area / listed | £258 LPA + £950–2,400 drawings | 8 weeks decision |
| Prior Approval (Larger Home Extension) | Single-storey rear over 4 m / 6 m up to 8 m total | £120 LPA + £950 drawings | 6 weeks decision |
| No application needed | True PD on a non-restricted house — risk lies with homeowner | £0 (but no certainty) | No application |
Source: GPDO 2015 (as amended), MHCLG planning portal fees 2024.
The questions homeowners ask before they commit.
How much does planning permission cost in 2026?
The standard householder application fee in England is £258. A Lawful Development Certificate is £258 (existing) or £580 (proposed). Major schemes are charged per square metre — typically £580+ for a single-dwelling new-build. Drawings + design statements add £950–£2,400. London + South East drawing fees average 30% above the rest of the UK.
How long does planning permission take?
Statutory determination is 8 weeks for householder, 13 weeks for major schemes. Pre-application advice (recommended in conservation areas) takes 4–6 weeks on top. Validation (the council confirming the application is complete) takes 1–2 weeks. Allow 12 weeks gross from submission to decision on an unproblematic householder application.
How long is planning permission valid for?
Three years to start works (under section 91 of the Town & Country Planning Act 1990). "Start" means a material operation — laying foundations, demolition, etc. — not just signing a contract. If you don't start within three years, you must reapply.
What is permitted development for a single-storey rear extension?
Class A of the GPDO 2015 allows: 4 m rear depth on a semi-detached / terrace, 6 m on a detached, single-storey, eaves height ≤ 3 m (4 m within 2 m of a boundary), maximum total ridge height 4 m. Side extensions up to half the original house width, single storey, eaves ≤ 4 m. Conservation areas and Article 4 directions tighten or remove these limits.
Do I need planning permission for a loft conversion?
Most loft conversions are permitted development if the addition is under 50 m³ (40 m³ for terraced houses), no extension beyond the existing roof slope at the front, and not on a designated land. Listed buildings, conservation areas, AONBs, and houses already extended often need full planning.
What's an Article 4 direction and how do I know if my house is in one?
An Article 4 direction is a formal notice from the council removing specified PD rights in a designated area — common in conservation areas, city-centre HMO restraint zones, and design-led suburbs. Your council's planning website will publish the Article 4 register. Your conveyancer's search at purchase reveals if your property is covered.
Going deeper.
Planning permission, fixed-fee.
TradeMatch architectural technologists handle pre-app, drawings, submission and case-officer liaison. 95% first-time approval across our network.