Two-storey extensions in Balham
Planning a bigger home in Balham? Compare extension types and guide prices below, then book a free site visit.
Balham at a glance
- Postcode districts
- SW12
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Clapham (1 mile), Brixton Hill (1.2 miles), Earlsfield (1.5 miles), Streatham (1.6 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 Balham (SW12) and the places around it, including Clapham (1.0 miles), Brixton Hill (1.2 miles) and Earlsfield.
Extensions available in Balham
Two-storey rear extensions
For homes in Balham: typical guide from £67,000.
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Two-storey side extensions
For homes in Balham: 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
Design, approvals and build for Balham homes. Guide from £86,500.
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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
Design, approvals and build for Balham homes. Guide from £30,000.
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Two-storey extensions for semi-detached houses
Balham guide price from £67,000, Standard spec.
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Two-storey extensions for detached houses
For homes in Balham: typical guide from £103,500.
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Kitchen extensions with bedrooms above
Guide from £67,000 (before kitchen units) in Balham, including VAT.
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Extra bedroom and en-suite extensions
Guide from £67,000 (plus en-suite) in Balham, including VAT.
Learn moreWhich type suits your house?
Rear and side extensions suit most semi-detached and detached houses with room around them. Terraced and town-centre homes can take a two-storey extension too, with more care over neighbours, light and access.
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 Balham
Balham 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 Balham
Do you cover Balham?
Yes. We cover Balham (SW12) and the surrounding area, including Clapham and Brixton Hill. The first site visit is free.
What does a two-storey extension cost in Balham?
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 Balham do you cover?
Everywhere around it, including Clapham (1 mile), Brixton Hill (1.2 miles) and Earlsfield (1.5 miles), and the rest of Greater London.