Two-storey extensions in Westminster
Need more room in Westminster? Two-storey and first-floor extensions add bedrooms and living space without moving. Here's everything we offer locally.
Westminster at a glance
- Postcode districts
- SW1, SW1A, SW1E, SW1H, SW1P and SW1X
- Area
- Greater London, England
- Price region
- London
- Nearest towns
- Pimlico (0.6 miles), St James's (0.7 miles), Soho (1.2 miles), Knightsbridge and Belgravia (1.4 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 Westminster we also work in Pimlico, St James's and Soho, and across the rest of Greater London. Postcode districts in and near Westminster: SW1, SW1A, SW1E, SW1H, SW1P and SW1X.
Extensions available in Westminster
Two-storey rear extensions
Design, approvals and build for Westminster homes. Guide from £67,000.
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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
For homes in Westminster: typical guide from £144,500.
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Part single, part two-storey extensions
Design, approvals and build for Westminster 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
For homes in Westminster: 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
From £103,500 in Westminster. Free visit to firm it up.
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Kitchen extensions with bedrooms above
Design, approvals and build for Westminster homes. Guide from £67,000 (before kitchen units).
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Extra bedroom and en-suite extensions
Guide from £67,000 (plus en-suite) in Westminster, including VAT.
Learn moreWhich type suits your house?
Start with what you need the space for. Bedrooms and an en-suite upstairs with a bigger kitchen below is the classic two-storey brief, but in Westminster we also design annexes, home offices and bedrooms over garages.
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 Westminster
Westminster 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 Westminster
Do you cover Westminster?
Yes. We cover Westminster (SW1, SW1A, SW1E, SW1H, SW1P and SW1X) and the surrounding area, including Pimlico and St James's. The first site visit is free.
What does a two-storey extension cost in Westminster?
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 Westminster do you cover?
Everywhere around it, including Pimlico (0.6 miles), St James's (0.7 miles) and Soho (1.2 miles), and the rest of Greater London.