Two-storey extensions in Northwood
Need more room in Northwood? Two-storey and first-floor extensions add bedrooms and living space without moving. Here's everything we offer locally.
Northwood at a glance
- Postcode districts
- HA6
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Northwood Hills (1.1 miles), Croxley Green (1.9 miles), Pinner (2.2 miles), Hatch End (2.2 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 Northwood we also work in Northwood Hills, Croxley Green and Pinner, and across the rest of Greater London. Postcode district in and near Northwood: HA6.
Extensions available in Northwood
Two-storey rear extensions
From £67,000 in Northwood. Free visit to firm it up.
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Two-storey side extensions
For homes in Northwood: typical guide from £103,500.
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Two-storey wraparound extensions
For homes in Northwood: typical guide from £144,500.
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Part single, part two-storey extensions
Northwood guide price from £86,500, Standard spec.
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Extensions over a garage
From £38,000 in Northwood. Free visit to firm it up.
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First-floor extensions
Design, approvals and build for Northwood homes. Guide from £30,000.
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Two-storey extensions for semi-detached houses
Guide from £67,000 in Northwood, including VAT.
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Two-storey extensions for detached houses
Northwood guide price from £103,500, Standard spec.
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Kitchen extensions with bedrooms above
Guide from £67,000 (before kitchen units) in Northwood, including VAT.
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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?
If you're not sure which type fits, that's what the free visit is for. We'll sketch the realistic options for your house in Northwood, with a rough idea of the approval route and cost for each.
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
Northwood 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
Do you cover Northwood?
Yes. We cover Northwood (HA6) and the surrounding area, including Northwood Hills and Croxley Green. The first site visit is free.
What does a two-storey extension cost in Northwood?
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 do you cover?
Everywhere around it, including Northwood Hills (1.1 miles), Croxley Green (1.9 miles) and Pinner (2.2 miles), and the rest of Greater London.