House Extensions in Lewisham

At Bigness Group, we design and build bespoke house extensions in Lewisham, helping homeowners create bright, functional, and beautifully finished spaces that fit modern living.
From Victorian terraces in Brockley and Telegraph Hill to detached homes in Blackheath and Catford, our extensions combine smart design, solid engineering, and lasting quality.

We manage every stage — planning, design, construction, and interior fit-out — so you enjoy a smooth, transparent process and a home that truly works for you.

Design and Build Services

Our Lewisham design-and-build team provides a complete, end-to-end solution:

• Measured survey, architectural design, and 3D visuals

• Planning and permitted development advice for Lewisham Council

• Structural engineering and Building Control compliance

• Interior layout, kitchen, and lighting design

• Dedicated project management with milestone updates

With Bigness Group, one skilled team handles every detail — guaranteeing accountability, clarity, and efficiency throughout.

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

Every Bigness project in Lewisham follows our proven high-quality process:

1. Groundworks & Foundations – Engineered for local soil and site conditions.

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

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

4. Windows & Glazing – High-performance, energy-efficient materials.

5. Interior Finishes – Plumbing, electrics, flooring, and bespoke joinery.

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

Local Knowledge

We have deep experience with Lewisham Council’s planning and conservation requirements, covering areas like Blackheath, Forest Hill, and Brockley.
Our understanding of local housing styles and planning standards ensures your extension fits perfectly with its surroundings — compliant, attractive, and built to last.

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.