Two-storey extensions in Northwood Hills
We design, get approval for and build two-storey extensions in Northwood Hills and the surrounding area. Choose the type of extension below or book a free site visit.
Northwood Hills at a glance
- Postcode districts
- HA6
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Northwood (1.1 miles), Pinner (1.2 miles), Hatch End (1.7 miles), Ruislip (1.9 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 HA6 in and around Northwood Hills, along with neighbouring Northwood, Pinner and Hatch End.
Extensions available in Northwood Hills
Two-storey rear extensions
Northwood Hills guide price from £67,000, Standard spec.
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Two-storey side extensions
For homes in Northwood Hills: typical guide from £103,500.
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Two-storey wraparound extensions
Our London guide starts at £144,500 for this type.
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Part single, part two-storey extensions
From £86,500 in Northwood Hills. Free visit to firm it up.
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Extensions over a garage
Design, approvals and build for Northwood Hills homes. Guide from £38,000.
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First-floor extensions
Northwood Hills guide price from £30,000, Standard spec.
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Two-storey extensions for semi-detached houses
For homes in Northwood Hills: typical guide from £67,000.
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Two-storey extensions for detached houses
Design, approvals and build for Northwood Hills homes. Guide from £103,500.
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Kitchen extensions with bedrooms above
From £67,000 (before kitchen units) in Northwood Hills. Free visit to firm it up.
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Extra bedroom and en-suite extensions
For homes in Northwood Hills: typical guide from £67,000 (plus en-suite).
Learn moreWhich type suits your house?
The boundaries usually decide it. Two-storey work close to a neighbour needs careful design for light and privacy, so at the visit in Northwood Hills we measure distances to every boundary before suggesting a type.
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 Northwood Hills
Northwood Hills 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 Northwood Hills
Do you cover Northwood Hills?
Yes. We cover Northwood Hills (HA6) and the surrounding area, including Northwood and Pinner. The first site visit is free.
What does a two-storey extension cost in Northwood Hills?
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 Northwood Hills do you cover?
Everywhere around it, including Northwood (1.1 miles), Pinner (1.2 miles) and Hatch End (1.7 miles), and the rest of Greater London.