Two-storey extensions in Harrow on the Hill
Homeowners in Harrow on the Hill can use us for the whole project or just the drawings and approvals. Start with a free visit.
Harrow on the Hill at a glance
- Postcode districts
- HA2
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Harrow (0.5 miles), Sudbury (Greater London) (1.2 miles), Brent (1.9 miles), Wealdstone (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 Harrow on the Hill we also work in Harrow, Sudbury (Greater London) and Brent, and across the rest of Greater London. Postcode district in and near Harrow on the Hill: HA2.
Extensions available in Harrow on the Hill
Two-storey rear extensions
Harrow on the Hill guide price from £67,000, Standard spec.
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Two-storey side extensions
Our London guide starts at £103,500 for this type.
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Two-storey wraparound extensions
Harrow on the Hill guide price from £144,500, Standard spec.
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Part single, part two-storey extensions
For homes in Harrow on the Hill: typical guide from £86,500.
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Extensions over a garage
For homes in Harrow on the Hill: typical guide from £38,000.
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First-floor extensions
For homes in Harrow on the Hill: typical guide from £30,000.
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Two-storey extensions for semi-detached houses
Our London guide starts at £67,000 for this type.
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Two-storey extensions for detached houses
Our London guide starts at £103,500 for this type.
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Kitchen extensions with bedrooms above
Design, approvals and build for Harrow on the Hill homes. Guide from £67,000 (before kitchen units).
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Extra bedroom and en-suite extensions
Design, approvals and build for Harrow on the Hill homes. Guide from £67,000 (plus en-suite).
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 Harrow on the Hill, 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 Harrow on the Hill
Harrow on the Hill 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 Harrow on the Hill
Do you cover Harrow on the Hill?
Yes. We cover Harrow on the Hill (HA2) and the surrounding area, including Harrow and Sudbury (Greater London). The first site visit is free.
What does a two-storey extension cost in Harrow on the Hill?
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 Harrow on the Hill do you cover?
Everywhere around it, including Harrow (0.5 miles), Sudbury (Greater London) (1.2 miles) and Brent (1.9 miles), and the rest of Greater London.