House Extensions in Southwark

At Bigness Group, we design and build bespoke house extensions in Southwark, helping homeowners across Central and South London create more space, light, and value.
From period terraces in Dulwich and Peckham to modern apartments in Bermondsey and Rotherhithe, we deliver extensions that merge architectural character with contemporary functionality.

We manage every stage — from planning and design to construction and finish — ensuring your extension is built beautifully, efficiently, and to the highest standards.

Design and Build Services

Our Southwark design-and-build team provides a complete, integrated service:

• Detailed measured survey and architectural design

• Planning permission and permitted development guidance through Southwark Council

• Structural engineering and Building Control coordination

• Kitchen, dining, and interior layout design

• Dedicated project management and milestone reporting

With Bigness Group, one team handles everything — giving you complete confidence, clarity, and consistent quality.

Types of Extensions We Build

We construct all major types of residential extensions across Redbridge, including:

• Glass Box Extensions – Clean, contemporary architecture for modern homes.
• Modern House Extensions – Contemporary builds for minimalist homes.
• Single-Storey Extensions – Create spacious kitchen or dining areas filled with light.
• Double-Storey Extensions – Add bedrooms or bathrooms while expanding downstairs living.
• Side-Return Extensions – Ideal for terraced homes in Ilford and Wanstead.
• Rear Extensions – Extend towards the garden for open-plan living.
• Wrap-Around Extensions – Combine side and rear layouts for maximum space.
• Conservatories & Orangeries – Elegant glazed spaces for all seasons.
• Loft & Garage Conversions with Extensions – Optimise unused areas for extra rooms or offices.
• Basement Extensions – Create gyms, cinemas, or private lounges below ground.

Construction Standards

Every Bigness project in Southwark follows our proven six-stage process:

1. Groundworks & Foundations – Tailored for South London’s soil and drainage conditions.

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

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

4. Windows & Glazing – Energy-efficient systems meeting all Building Regulations.

5. Interior Finishes – Plumbing, electrical, flooring, and bespoke carpentry.

6. Final Approval & Warranty – Building Control certification and long-term guarantee.

Local Knowledge

We have strong experience with Southwark Council’s planning and conservation policies, including heritage zones around Dulwich Village, Bermondsey Street, and Borough Market.
Our designs respect local architectural character while meeting modern living standards — ensuring quick approvals and lasting results.

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.