Two-storey extensions in Hornsey
Everything for a two-storey extension in Hornsey, in one place: types, guide prices for London, the approval rules in England and how to get started.
Hornsey at a glance
- Postcode districts
- N8
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Crouch End (0.5 miles), Muswell Hill (0.9 miles), Wood Green (0.9 miles), Stroud Green (1 mile)
- 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 Hornsey (N8) and the places around it, including Crouch End (0.5 miles), Muswell Hill (0.9 miles) and Wood Green.
Extensions available in Hornsey
Two-storey rear extensions
Hornsey guide price from £67,000, Standard spec.
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Two-storey side extensions
Guide from £103,500 in Hornsey, including VAT.
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Two-storey wraparound extensions
From £144,500 in Hornsey. Free visit to firm it up.
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Part single, part two-storey extensions
From £86,500 in Hornsey. Free visit to firm it up.
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Extensions over a garage
Guide from £38,000 in Hornsey, including VAT.
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First-floor extensions
For homes in Hornsey: typical guide from £30,000.
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Two-storey extensions for semi-detached houses
Design, approvals and build for Hornsey homes. Guide from £67,000.
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Two-storey extensions for detached houses
Hornsey guide price from £103,500, Standard spec.
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Kitchen extensions with bedrooms above
Hornsey guide price from £67,000 (before kitchen units), Standard spec.
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Extra bedroom and en-suite extensions
For homes in Hornsey: typical guide from £67,000 (plus en-suite).
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 Hornsey
Hornsey 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 Hornsey
Do you cover Hornsey?
Yes. We cover Hornsey (N8) and the surrounding area, including Crouch End and Muswell Hill. The first site visit is free.
What does a two-storey extension cost in Hornsey?
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 Hornsey do you cover?
Everywhere around it, including Crouch End (0.5 miles), Muswell Hill (0.9 miles) and Wood Green (0.9 miles), and the rest of Greater London.