Two-storey extensions in New Barnet
Everything for a two-storey extension in New Barnet, in one place: types, guide prices for London, the approval rules in England and how to get started.
New Barnet at a glance
- Postcode districts
- EN4
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- East Barnet (0.6 miles), Barnet (1.1 miles), Cockfosters (1.2 miles), Hadley Wood (1.2 miles)
- Approvals
- Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission.
Around New Barnet we also work in East Barnet, Barnet and Cockfosters, and across the rest of Greater London. Postcode district in and near New Barnet: EN4.
Extensions available in New Barnet
Two-storey rear extensions
Design, approvals and build for New Barnet homes. Guide from £67,000.
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Two-storey side extensions
For homes in New Barnet: typical guide from £103,500.
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Two-storey wraparound extensions
For homes in New Barnet: typical guide from £144,500.
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Part single, part two-storey extensions
From £86,500 in New Barnet. Free visit to firm it up.
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Extensions over a garage
Design, approvals and build for New Barnet homes. Guide from £38,000.
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First-floor extensions
From £30,000 in New Barnet. Free visit to firm it up.
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Two-storey extensions for semi-detached houses
From £67,000 in New Barnet. Free visit to firm it up.
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Two-storey extensions for detached houses
New Barnet guide price from £103,500, Standard spec.
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Kitchen extensions with bedrooms above
New Barnet guide price from £67,000 (before kitchen units), Standard spec.
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Extra bedroom and en-suite extensions
From £67,000 (plus en-suite) in New Barnet. Free visit to firm it up.
Learn moreWhich type suits your house?
Start with what you need the space for. Bedrooms and an en-suite upstairs with a bigger kitchen below is the classic two-storey brief, but in New Barnet we also design annexes, home offices and bedrooms over garages.
Also available in Greater London
- Two-storey front extensions
- Two-storey extensions for end-of-terrace houses
- Two-storey annexe extensions
- Garage conversions with a room above
- Two-storey extension plans and drawings
- Planning permission for two-storey extensions
- Structural engineering for two-storey extensions
- Building regulations for two-storey extensions
- Party wall notices for extensions
- Design and build two-storey extensions
Rules for New Barnet
New Barnet is in England. Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission. Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
The full England rules explained
Questions about extensions in New Barnet
Do you cover New Barnet?
Yes. We cover New Barnet (EN4) and the surrounding area, including East Barnet and Barnet. The first site visit is free.
What does a two-storey extension cost in New Barnet?
Using our London guide, a two-storey rear extension with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) is about £67,000–£90,500 including VAT. An extension over a garage is about £38,000–£55,000.
Which other places near New Barnet do you cover?
Everywhere around it, including East Barnet (0.6 miles), Barnet (1.1 miles) and Cockfosters (1.2 miles), and the rest of Greater London.