London · UK introductions
House Extensions in London
Side-return, rear and wraparound extensions for London homes. Planning notes, indicative costs and quotes from independent builders.
A house extension is one of the most common ways London homeowners add living space without moving. Side-return, rear and wraparound designs are typical on Victorian and Edwardian terraces; suburban semis often suit two-storey side extensions.
Whether you need planning permission depends on your property, conservation status and the size of the works. Many houses can use permitted development for modest rear extensions, but flats, listed buildings and Article 4 areas usually need an application. Always check with your local council.
Home Builders publishes guides and introductions. We do not design or build extensions ourselves. With your consent we pass quote requests to up to 3 independent builders who advertise with us.
London boroughs
More boroughs: all 32 London boroughs & the City.
Questions
Do I need planning permission for a rear extension?
Often a modest single-storey rear extension on a house can use permitted development, but conservation areas, flats and larger schemes usually need permission. A Lawful Development Certificate is wise even when PD applies.
How much does a London house extension cost?
Indicative 2026 ranges are roughly £2,500–£4,500+ per m² depending on borough and specification, before fees, contingency and VAT. Request local quotes for a firm figure.
Request quotes · UK introductions
Request quotes for house extensions
Tell us about your extension, loft or renovation anywhere in the UK. With your consent, we pass your enquiry to up to 3 independent builders who advertise with us, so they can contact you with quotes. We do not carry out building work ourselves.
- Free to use, no obligation
- Up to 3 builders, only with your consent
- Always check each builder’s insurance, references and written quote