House Extensions in Sutton

At Bigness Group, we design and build durable, high-quality house extensions in Sutton, helping homeowners add space, light, and value to their properties.
From family homes in Carshalton and Cheam to semi-detached houses in Wallington and Belmont, our bespoke extensions transform your home’s functionality while maintaining its charm and character.

We handle everything — from design and planning to construction and finish — ensuring your project runs smoothly, efficiently, and to the highest standards.

Design and Build Services

Our Sutton design-and-build team delivers complete end-to-end project management:

• Detailed measured survey and bespoke architectural design

• Planning and permitted development advice for Sutton Council

• Structural calculations and Building Control compliance

• Interior planning, kitchen, and lighting design

• Dedicated project management with milestone tracking

With Bigness Group, one skilled team manages every phase — ensuring clarity, consistency, and premium results from start to finish.

Types of Extensions We Build

We deliver every major type of house extension across Sutton, including:

• Glass Box Extensions – Contemporary designs with clean lines and glass features.
• Modern House Extensions – Contemporary builds for minimalist homes.
• Single-Storey Extensions – Expand your ground floor with open, light-filled living areas.
• Double-Storey Extensions – Add new rooms above while increasing downstairs space.
• Side-Return Extensions – Ideal for semi-detached and terraced homes in Cheam or Wallington.
• Rear Extensions – Create spacious, modern kitchen and dining areas.
• Wrap-Around Extensions – Combine side and rear layouts for seamless open-plan design.
• Conservatories & Orangeries – Classic glazed additions for year-round comfort.
• Loft & Garage Conversions with Extensions – Optimise existing spaces for added functionality.
• Basement Extensions – Create gyms, cinemas, or private lounges below ground.

Construction Standards

Every Bigness project in Sutton follows a precise six-step process to guarantee quality:

1. Groundworks & Foundations – Engineered to match local soil and property type.

2. Structural Framework – RSJs and beams installed for strength and open layouts.

3. Walls & Roofs – Brick match, render, or cladding with full insulation.

4. Windows & Glazing – Energy-efficient systems meeting all current regulations.

5. Interior Finishes – Plumbing, electrics, flooring, and joinery installed to specification.

6. Building Control & Warranty – Final inspection, certification, and workmanship guarantee.

Local Knowledge

We’re experienced with Sutton Council’s planning and building regulations, ensuring your project meets all local requirements.
From conservation areas in Carshalton Beeches to modern developments in Hackbridge, our knowledge of the borough’s housing styles ensures seamless planning and execution.

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.