Two-storey extensions in Canonbury
Everything for a two-storey extension in Canonbury, in one place: types, guide prices for London, the approval rules in England and how to get started.
Canonbury at a glance
- Postcode districts
- N1
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Highbury (0.6 miles), Islington (0.7 miles), Barnsbury (1.1 miles), Hackney (1.5 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 postcode district N1 in and around Canonbury, along with neighbouring Highbury, Islington and Barnsbury.
Extensions available in Canonbury
Two-storey rear extensions
Our London guide starts at £67,000 for this type.
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Two-storey side extensions
Design, approvals and build for Canonbury homes. Guide from £103,500.
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Two-storey wraparound extensions
For homes in Canonbury: typical guide from £144,500.
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Part single, part two-storey extensions
Our London guide starts at £86,500 for this type.
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Extensions over a garage
From £38,000 in Canonbury. Free visit to firm it up.
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First-floor extensions
Canonbury guide price from £30,000, Standard spec.
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Two-storey extensions for semi-detached houses
For homes in Canonbury: typical guide from £67,000.
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Two-storey extensions for detached houses
Design, approvals and build for Canonbury homes. Guide from £103,500.
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Kitchen extensions with bedrooms above
Canonbury guide price from £67,000 (before kitchen units), Standard spec.
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Extra bedroom and en-suite extensions
For homes in Canonbury: typical guide from £67,000 (plus en-suite).
Learn moreWhich type suits your house?
Rear, side, wraparound or over the garage: each adds space in a different way. For most houses in Greater London, one or two of these will clearly suit the plot better than the rest, and we'll tell you which.
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 Canonbury
Canonbury 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 Canonbury
Do you cover Canonbury?
Yes. We cover Canonbury (N1) and the surrounding area, including Highbury and Islington. The first site visit is free.
What does a two-storey extension cost in Canonbury?
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 Canonbury do you cover?
Everywhere around it, including Highbury (0.6 miles), Islington (0.7 miles) and Barnsbury (1.1 miles), and the rest of Greater London.