Two-storey extensions in Finchley
We design, get approval for and build two-storey extensions in Finchley and the surrounding area. Choose the type of extension below or book a free site visit.
Finchley at a glance
- Postcode districts
- N3
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Golders Green (1.7 miles), Friern Barnet (1.8 miles), Totteridge (2.2 miles), Muswell Hill (2.4 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.
We cover Finchley (N3) and the places around it, including Golders Green (1.7 miles), Friern Barnet (1.8 miles) and Totteridge.
Extensions available in Finchley
Two-storey rear extensions
Finchley guide price from £67,000, Standard spec.
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Two-storey side extensions
Design, approvals and build for Finchley homes. Guide from £103,500.
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Two-storey wraparound extensions
Guide from £144,500 in Finchley, including VAT.
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Part single, part two-storey extensions
Guide from £86,500 in Finchley, including VAT.
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Extensions over a garage
Design, approvals and build for Finchley homes. Guide from £38,000.
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First-floor extensions
Guide from £30,000 in Finchley, including VAT.
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Two-storey extensions for semi-detached houses
For homes in Finchley: typical guide from £67,000.
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Two-storey extensions for detached houses
Finchley guide price from £103,500, Standard spec.
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Kitchen extensions with bedrooms above
For homes in Finchley: typical guide from £67,000 (before kitchen units).
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Extra bedroom and en-suite extensions
Our London guide starts at £67,000 (plus en-suite) for this type.
Learn moreWhich type suits your house?
Rear and side extensions suit most semi-detached and detached houses with room around them. Terraced and town-centre homes can take a two-storey extension too, with more care over neighbours, light and access.
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 Finchley
Finchley 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 Finchley
Do you cover Finchley?
Yes. We cover Finchley (N3) and the surrounding area, including Golders Green and Friern Barnet. The first site visit is free.
What does a two-storey extension cost in Finchley?
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 Finchley do you cover?
Everywhere around it, including Golders Green (1.7 miles), Friern Barnet (1.8 miles) and Totteridge (2.2 miles), and the rest of Greater London.