Two-storey extensions in Barnes
Everything for a two-storey extension in Barnes, in one place: types, guide prices for London, the approval rules in England and how to get started.
Barnes at a glance
- Postcode districts
- SW13
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Mortlake (0.9 miles), East Sheen (1.1 miles), Chiswick (1.4 miles), Roehampton (1.5 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 Barnes we also work in Mortlake, East Sheen and Chiswick, and across the rest of Greater London. Postcode district in and near Barnes: SW13.
Extensions available in Barnes
Two-storey rear extensions
Barnes guide price from £67,000, Standard spec.
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Two-storey side extensions
Guide from £103,500 in Barnes, including VAT.
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Two-storey wraparound extensions
Design, approvals and build for Barnes homes. Guide from £144,500.
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Part single, part two-storey extensions
From £86,500 in Barnes. Free visit to firm it up.
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Extensions over a garage
Guide from £38,000 in Barnes, including VAT.
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First-floor extensions
Design, approvals and build for Barnes homes. Guide from £30,000.
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Two-storey extensions for semi-detached houses
Barnes guide price from £67,000, Standard spec.
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Two-storey extensions for detached houses
For homes in Barnes: typical guide from £103,500.
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Kitchen extensions with bedrooms above
From £67,000 (before kitchen units) in Barnes. Free visit to firm it up.
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Extra bedroom and en-suite extensions
Guide from £67,000 (plus en-suite) in Barnes, including VAT.
Learn moreWhich type suits your house?
Which type suits your house in Barnes depends mostly on where you have room. A deep garden points to a rear extension; space beside the house points to a side or over-garage extension; a house that already has a single-storey extension can often take a first floor on top.
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 Barnes
Barnes 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 Barnes
Do you cover Barnes?
Yes. We cover Barnes (SW13) and the surrounding area, including Mortlake and East Sheen. The first site visit is free.
What does a two-storey extension cost in Barnes?
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 Barnes do you cover?
Everywhere around it, including Mortlake (0.9 miles), East Sheen (1.1 miles) and Chiswick (1.4 miles), and the rest of Greater London.