Two-storey extensions in Barnet
Planning a bigger home in Barnet? Compare extension types and guide prices below, then book a free site visit.
Barnet at a glance
- Postcode districts
- EN5
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- New Barnet (1.1 miles), Totteridge (1.2 miles), East Barnet (1.7 miles), Hadley Wood (1.7 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 Barnet we also work in New Barnet, Totteridge and East Barnet, and across the rest of Greater London. Postcode district in and near Barnet: EN5.
Extensions available in Barnet
Two-storey rear extensions
Design, approvals and build for Barnet homes. Guide from £67,000.
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Two-storey side extensions
For homes in Barnet: typical guide from £103,500.
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Two-storey wraparound extensions
Design, approvals and build for Barnet homes. Guide from £144,500.
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Part single, part two-storey extensions
Barnet guide price from £86,500, Standard spec.
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Extensions over a garage
Design, approvals and build for Barnet homes. Guide from £38,000.
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First-floor extensions
For homes in Barnet: typical guide from £30,000.
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Two-storey extensions for semi-detached houses
From £67,000 in Barnet. Free visit to firm it up.
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Two-storey extensions for detached houses
Our London guide starts at £103,500 for this type.
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Kitchen extensions with bedrooms above
Guide from £67,000 (before kitchen units) in Barnet, including VAT.
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Extra bedroom and en-suite extensions
Guide from £67,000 (plus en-suite) in Barnet, including VAT.
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 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 Barnet
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 Barnet
Do you cover Barnet?
Yes. We cover Barnet (EN5) and the surrounding area, including New Barnet and Totteridge. The first site visit is free.
What does a two-storey extension cost in 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 Barnet do you cover?
Everywhere around it, including New Barnet (1.1 miles), Totteridge (1.2 miles) and East Barnet (1.7 miles), and the rest of Greater London.