A house extension can transform your home, adding valuable living space. Costs cover foundations, structural work, roofing, glazing, internal fit-out, and connection to existing services. In Kensington (W8, W14), costs reflect the area's Prime Central London market position, with a 25% premium over London averages.
Kensington is a royal borough known for its grand Victorian and Edwardian architecture, Kensington Palace, and world-class cultural institutions. Properties range from large family houses to elegant mansion flats.
| Specification | Price per sqm | Typical 25sqm Project | Includes |
|---|---|---|---|
|
Standard
Quality materials, clean design
|
£3,125 – £4,000 | £78,125 – £100,000 | All structural work, standard fixtures, full fit-out and decoration |
|
Premium
Designer brands, bespoke elements
|
£4,000 – £5,000 | £100,000 – £125,000 | Premium materials, designer fixtures, underfloor heating, smart controls |
|
Luxury
Finest materials, fully bespoke
|
£5,000 – £6,875 | £125,000 – £171,875 | Bespoke joinery, natural stone, top-tier appliances, architectural detailing |
Prices include VAT and are based on Kensington (W8, W14) market rates. Prime Central London pricing reflects the premium specification expectations and specialist requirements typical in this area. Actual costs depend on site-specific factors. All prices are guide estimates for 2025.
Here's what a typical 25sqm house extension project would cost in Kensington at each specification level.
RBKC has extensive conservation area coverage across Kensington. The council has some of London's strictest planning policies, particularly regarding basement developments and roof alterations.
Key streets and roads in Kensington include Kensington Square, Phillimore Gardens, Holland Park, Camden Hill Road, Victoria Road. Properties in these locations often have specific architectural characteristics that influence renovation costs, including RBKC stringent planning requirements, basement construction method statements required, noise and construction hour restrictions, high-value period features requiring specialist restoration.
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