House Extensions in Lambeth

At Bigness Group, we specialise in premium house extensions in Lambeth, transforming homes across South London with design excellence and construction precision.
From Victorian terraces in Clapham and Brixton to townhouses in Kennington and detached homes in Streatham, our bespoke extensions bring light, space, and value — built to modern standards with timeless appeal.

We handle everything — from initial design and planning permission to structural engineering, interiors, and build — ensuring a seamless, stress-free process from start to finish.

Design and Build Services

Our Lambeth design-and-build team offers a complete turnkey service:

• Full measured survey and architectural design

• Planning and permitted development management with Lambeth Council

• Structural calculations and Building Control compliance

• Interior layout, kitchen, and lighting design

• Dedicated project management with milestone tracking

With one experienced team overseeing every detail, we guarantee quality, accountability, and on-time delivery for every project.

Types of Extensions We Build

We deliver all major types of house extensions in Lambeth, including:

• Glass Box Extensions – Architectural statements for contemporary homes.
• Modern House Extensions – Minimalist designs for a contemporary aesthetic.
• Single-Storey Extensions – Ideal for kitchens and open-plan living spaces.
• Double-Storey Extensions – Add bedrooms, bathrooms, or studies above ground level.
• Side-Return Extensions – Perfect for terraced homes in Clapham, Brixton, and Stockwell.
• Rear Extensions – Combine side and rear expansion for ultimate space.
• Wrap-Around Extensions – Combine side and rear layouts for a seamless flow.
• Conservatories & Orangeries – Elegant glazed rooms for year-round comfort.
• Loft & Garage Conversions with Extensions – Expand upwards or re-purpose existing structures.
• Basement Extensions – Create gyms, cinemas, or private lounges below ground.

Construction Standards

Each Bigness project in Lambeth follows our rigorous six-phase build framework:

1. Groundworks & Foundations – Engineered for South London’s clay soil conditions.

2. Structural Steelwork – RSJs and frames installed for stability and open layouts.

3. Walls & Roofing – Brick match, render, or cladding with warm-roof insulation.

4. Windows & Glazing – Energy-efficient materials meeting Part L regulations.

5. Interior Finishes – Electrical, plumbing, flooring, and carpentry work to specification.

6. Final Certification & Warranty – Building Control sign-off and workmanship guarantee.

Local Knowledge

We are highly familiar with Lambeth Council’s planning and conservation requirements, including areas such as Clapham Park, Herne Hill, and Kennington.
Our expertise ensures your extension gains swift approval and complements Lambeth’s architectural character — from heritage terraces to modern urban homes.

Costs and Financing

Every extension is unique, but here’s a general guide:

💡 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.