Whether your extension needs full planning permission, a lawful development certificate, or neither, depends on your property and your council. Our in-house architects assess the route and manage the entire application across London.
Many house extensions in England can be built under Permitted Development (PD) rights without a full planning application — but many cannot. Whether yours qualifies depends on the size and position of the extension, the type and history of your property, and whether it sits in a conservation area, an Article 4 Direction zone, or is listed. Getting this judgement right at the start protects you from enforcement action and wasted cost. We assess every project against current Planning Portal rules and recommend the correct route.
If your extension falls within PD limits, no planning application is needed — but we strongly recommend a Lawful Development Certificate to prove it, which protects you at resale.
Larger or two-storey extensions, and most work in sensitive locations, need a full householder application, usually determined within about 8 weeks of validation.
In a conservation area or under an Article 4 Direction, PD rights are restricted or removed, so works that would be permitted elsewhere need consent. We know the North London designations well.
If your property is listed, Listed Building Consent is required for most alterations in addition to planning permission, and the bar for acceptable change is higher.
An LDC is a formal council confirmation that your works are lawful under PD. It is the safe way to evidence permitted development and avoids disputes when you sell.
Larger single-storey rear extensions under PD use a prior-approval 'neighbour consultation' process. We prepare and manage this on your behalf.
Timescales below are typical council determination periods from a validated submission; design and preparation happen before this. Planning fees are set nationally and change periodically — see the Planning Portal for current fees.
| Planning Route | Typical Determination | When It Applies |
|---|---|---|
| Lawful Development Certificate | ~8 weeks | Confirming a Permitted Development extension |
| Larger Home Extension (prior approval) | ~6 weeks (42 days) | Larger single-storey rear under PD |
| Householder planning application | ~8 weeks | Most extensions outside PD |
| Listed Building Consent | ~8 weeks | Alterations to a listed property |
Every project is priced individually. Use our cost calculator or book a free consultation for a detailed, fixed quotation.
We check your property's planning history and designations and assess the proposed extension against current Permitted Development rules to determine the correct route.
Our architects design the extension to satisfy your council's local plan, daylight/overlooking tests and (where relevant) conservation-area guidance, maximising the chance of approval.
We prepare the drawings, design and access statement and supporting documents, then submit the LDC, prior-approval or householder application and pay the fee on your behalf.
We act as your agent through validation, the consultation period and any case-officer queries, negotiating amendments rather than risking refusal where possible.
On approval, we discharge any pre-commencement conditions and move seamlessly into structural design, Building Regulations and construction.
We are adding photographed, costed case studies for this service. To see comparable completed schemes, book a consultation or browse our case study portfolio.
Book a free consultation. Our architects will assess your property, tell you exactly which route applies, and manage the entire application from design to decision.