House Extensions in Kensington and Chelsea
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At Bigness Group, we design and build premium house extensions in Kingston upon Thames, helping homeowners expand their space, upgrade functionality, and elevate property value.
From period homes in Surbiton and Hampton Wick to detached family properties in New Malden and Berrylands, we create bespoke extensions that blend modern design with timeless craftsmanship.
We manage every stage — from concept and planning to engineering, interiors, and construction — ensuring your extension is beautifully designed, expertly built, and fully compliant.
Design and Build Services
Our Kingston design-and-build team provides a complete, end-to-end service:
- Full measured survey and architectural design
- Planning and permitted development support for Kingston Council
- Structural calculations and Building Control coordination
- Kitchen and interior layout optimisation
- Dedicated project management with transparent milestone
With one skilled team handling every phase, you enjoy a smooth process and a finished extension that perfectly matches your home and lifestyle.
Types of Extensions We Build
We construct all major types of house extensions across Kingston upon Thames, including:
• Glass Box Extensions – Architectural statements for contemporary homes.
• Modern House Extensions – Architectural masterpieces for contemporary living.
• Single-Storey Extensions – Create open-plan living areas with garden access.
• Double-Storey Extensions – Expand bedrooms and living space for growing families.
• Side-Return Extensions – Perfect for Victorian or Edwardian homes in Surbiton or Hampton Wick.
• Rear Extensions – Open up your home with natural light and modern glazing.
• Wrap-Around Extensions – Combine side and rear layouts for a seamless flow.
• Conservatories & Orangeries – Elegant, energy-efficient glazed living spaces.
• Loft & Garage Conversions with Extensions – Add extra rooms without changing your footprint.
• Basement Extensions – Create gyms, cinemas, or private lounges below ground.
Construction Standards
Every Bigness project in Kingston is built to industry-leading standards:
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Groundworks & Foundations – Engineered to local soil and drainage conditions.
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Structural Steelwork – RSJs and beams installed for stability and open layouts.
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Walls & Roofing – Brick match, render, or cladding with high-performance insulation.
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Windows & Glazing – Energy-efficient materials compliant with Part L standards.
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Interior Finishes – Electrical, plumbing, flooring, and joinery completed to spec.
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Final Certification – Building Control approval and long-term workmanship warranty.
Local Knowledge
We have extensive experience working with Kingston Council’s planning and conservation policies, covering sensitive areas like Hampton Wick, Coombe Hill, and Surbiton.
Our deep understanding of local architectural character ensures your extension complements its surroundings while meeting all legal and environmental standards.
Costs and Financing
Every extension is unique, but here’s a general guide:
| Type | Typical Cost Range (2025) |
|---|---|
| Single-Storey Extension | £45,000 – £85,000 |
| Double-Storey Extension | £75,000 – £130,000 |
| Wrap-Around Extension | £90,000 – £160,000 |
| Side-Return Extension | £40,000 – £75,000 |
💡 Factors include size, materials, access, and specification level.
We provide transparent quotes with detailed breakdowns and stage payments.
Financing options may be available through our partner lenders for eligible clients — ask our team for guidance on home improvement financing.
The Process
1. Consultation & Site Visit – We meet you on-site to discuss ideas, goals, and feasibility.
2. Design & Planning – We prepare drawings, handle permissions, and finalise the budget.
3. Construction Phase – Our project manager oversees all work, ensuring safety and communication at every step.
4. Completion & Aftercare – Once finished, we conduct final inspections and provide warranty documentation.
We also offer optional maintenance plans to keep your new space performing at its best.
Why Choose Bigness Group
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Local expertise: in-depth understanding of Kingston’s planning rules and building standards.
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Comprehensive delivery: design, permissions, build, and interiors in one contract.
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Accredited professionals: fully compliant with UK Building Regulations.
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Transparent pricing: itemised quotes and milestone billing.
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Proven track record: trusted by homeowners across South West London.
Bigness Group brings experience, precision, and care to every project — creating homes that truly work for the people who live in them.
FAQ
Do I need planning permission for an extension in Kingston?
Some smaller extensions are allowed under permitted development, but most two-storey or listed properties require full planning approval. We handle it all for you.
How long does construction take?
Typically 8–14 weeks for single-storey builds and 12–20 weeks for larger extensions.
Can you work on riverside or conservation homes?
Yes — we’re experienced with conservation and flood-adjacent properties near the Thames.
Do you offer full interior and kitchen design?
Absolutely. We integrate interior design and fit-outs within your project for a seamless finish.
Our Recent Projects in Kingston upon Thames
Recent Kingston projects include a wrap-around kitchen extension in Surbiton, a two-storey family build in New Malden, and a glass rear extension overlooking the Thames.
Each demonstrates Bigness Group’s signature craftsmanship, energy-efficient design, and modern aesthetic — built for comfort and longevity.
House Extensions in London by Borough
Bigness Group designs and builds bespoke house extensions across all London boroughs, including Kingston upon Thames and the wider South West area. Our expertise in planning and construction ensures smooth approvals, architectural harmony, and superior craftsmanship.
Barking and Dagenham / Barnet / Bexley / Brent / Bromley / Camden / Croydon / Ealing / Enfield / Greenwich / Hackney / Hammersmith and Fulham / Haringey / Harrow / Havering / Hillingdon / Hounslow / Islington / Kensington and Chelsea / Kingston upon Thames / Lambeth / Lewisham / Merton / Newham / Redbridge / Richmond upon Thames / Southwark / Sutton / Tower Hamlets / Waltham Forest / Wandsworth / Westminster
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