Barnet Council (London Borough of Barnet)
Building in Barnet: a local guide
Housing stock, planning and conservation notes, and indicative costs for extensions, lofts and renovations in Barnet, plus quotes from independent local builders.
Homes in Barnet
Barnet is London's most populous borough, with large areas of interwar semi-detached and detached houses, Edwardian homes in Finchley, and the Arts and Crafts houses of Hampstead Garden Suburb.
Typical projects here
Two-storey side extensions, rear extensions, hip-to-gable lofts and full renovations of 1930s homes.
Planning and conservation in Barnet
Planning and building control in this area are handled by Barnet Council (London Borough of Barnet). Barnet has many conservation areas. In Hampstead Garden Suburb, the Hampstead Garden Suburb Trust's scheme of management means works may need Trust consent in addition to planning permission. Before you design, check whether your property is in a conservation area, is listed or is covered by an Article 4 direction; these change what you can build without permission. Our guide to permitted development in London explains the national rules, and loft conversion regulations covers roof works.
Larger plots in Barnet often suit bigger extensions than are possible in inner London.
Typical building costs in Barnet
Building costs in Barnet typically follow outer London rates of about £2,500 to £3,500 per m² for standard residential work, with high specifications and tricky access at the upper end or above. Budget on top for professional fees (about 15%), consents and contingency (8–15%) and VAT at 20% on extensions and renovations. These are indicative industry ranges for 2026, not a quote; see our London cost guide or request fixed quotes from local builders.
Neighbourhoods in Barnet
Questions about building in Barnet
Can I request quotes from builders in Barnet?
Yes. Quote requests are accepted from anywhere in Barnet, including Finchley, Hendon, Golders Green, Mill Hill, Edgware, Whetstone, High Barnet, Hampstead Garden Suburb, across London and the wider UK. With your consent, we pass your enquiry to up to 3 local builders who advertise with us.
Do I need planning permission for an extension in Barnet?
It depends on your property. Houses outside conservation areas may be able to use permitted development, while flats, conservation areas and Article 4 directions usually mean an application to Barnet Council (London Borough of Barnet). A Lawful Development Certificate gives certainty.
Should I check a builder’s insurance?
We ask every builder who advertises with us to provide proof of current public liability insurance before they are listed. Always check each builder’s insurance, references, written quote and trade body membership yourself before work starts.
Nearby: Ealing · Hammersmith & Fulham · Camden · Islington · Wandsworth · all London boroughs · UK areas
Request quotes · UK introductions
Request quotes for your Barnet project
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