Two-storey extensions in Isleworth
From over-garage bedrooms to full wraparounds, we cover every kind of two-storey extension in Isleworth.
Isleworth at a glance
- Postcode districts
- TW7
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Osterley (0.6 miles), Hounslow (0.9 miles), Heston (1.5 miles), Brentford (1.7 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 Isleworth (TW7) and the places around it, including Osterley (0.6 miles), Hounslow (0.9 miles) and Heston.
Extensions available in Isleworth
Two-storey rear extensions
Our London guide starts at £67,000 for this type.
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Two-storey side extensions
Isleworth guide price from £103,500, Standard spec.
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Two-storey wraparound extensions
Guide from £144,500 in Isleworth, including VAT.
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Part single, part two-storey extensions
Isleworth guide price from £86,500, Standard spec.
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Extensions over a garage
Our London guide starts at £38,000 for this type.
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First-floor extensions
Isleworth guide price from £30,000, Standard spec.
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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
Guide from £103,500 in Isleworth, including VAT.
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Kitchen extensions with bedrooms above
Guide from £67,000 (before kitchen units) in Isleworth, including VAT.
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Extra bedroom and en-suite extensions
Isleworth guide price from £67,000 (plus en-suite), Standard spec.
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 Isleworth, 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 Isleworth
Isleworth 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 Isleworth
Do you cover Isleworth?
Yes. We cover Isleworth (TW7) and the surrounding area, including Osterley and Hounslow. The first site visit is free.
What does a two-storey extension cost in Isleworth?
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 Isleworth do you cover?
Everywhere around it, including Osterley (0.6 miles), Hounslow (0.9 miles) and Heston (1.5 miles), and the rest of Greater London.