Rear Extensions
Rear Extensions
Maximise your living space with a professionally built rear extension. We build from your plans with fixed pricing and guaranteed timelines. Optional design services available.
- Most projects qualify for Permitted Development (no planning needed)
- Single storey from £35,000, double storey from £65,000
- Typical timeline 8 to 14 weeks depending on size
- Fixed price contract with no hidden extras
- 15 year structural warranty included
Industry average
£42,000 – £55,000
Our starting price
£35,000
Typical single storey rear extension around 14 to 16 m². Our internal supply chains and optimised project planning keep builds under budget.
Why we're more affordable
- Internal supply chains — we source materials at trade prices
- Optimised systems — efficient planning reduces wasted time and materials
- Strong project management — we complete on time, keeping costs under control
Fixed price quote within 5 working days
Verified client reviews and 350+ completed projects
About this service
About rear extensions
A rear extension extends your property backwards into your garden, creating additional living space on the ground floor. Most rear extensions in London are built under Permitted Development rights, avoiding the need for full planning permission. Single storey rear extensions with a straightforward specification typically start from £35,000 and take 8 to 12 weeks to complete. We specialise in traditional brick built extensions that seamlessly match your existing property.
Who it's for
Homeowners needing more space without moving. Rear extensions are ideal for growing families, creating larger kitchens, adding dining areas, or building ground floor bedrooms. They work particularly well for Victorian and Edwardian terraced houses common across London.
GOV.UK: Permitted Development RightsScope
What's Included
- Initial consultation and site survey
- Construction from your approved plans
- Building Regulations approval and inspections
- Complete build from foundations to final decoration
- Optional: Architectural drawings and structural calculations (quoted separately)
Process
How it Works
Free Consultation
We visit your property, discuss your requirements, review your plans, and provide a fixed price quote within 5 working days.
Plan Review & Quote
We review your architectural and structural drawings, then provide a detailed fixed price construction quote.
Construction
Groundworks, foundations, brickwork, roofing, first and second fix, decoration. Weekly progress reports throughout.
Reviews
What homeowners say
What homeowners say about working with us on house extensions.
“We hired Brits Construction to carry out a single-story extension on our home, and we couldn't be happier with the final result and the overall quality of the work. Syed was incredibly detail-oriented and consistently checked in with us to ensure everything was on track. His thoughtful suggestions really enhanced both the functionality and design of the extension. What stood out most about working with Syed and his team was their dedication to clear and timely communication. Syed was always quick to respond to any questions, kept us fully informed about the progress, and was transparent about any site updates—this made the entire process much smoother and less stressful. In short, Brits Construction delivered a high-quality extension with exceptional communication along the way. We would definitely recommend them to others.”
James Swinden
Single story extension ·
Review on Trustpilot
“Bricks Construction Services did our single storey rear extension and honestly did a great job. We were really struggling to find matching bricks because the house is in a conservation area, but Saeed somehow managed to source them when we could not find them anywhere. Really good team, very professional and they clearly have great contacts for materials. Would definitely recommend them for conservation area work.”
Linda Torres
Review on Google
“We hired Brits Construction to complete a single story extension on our home. Overall, we are very satisfied with the final result and the quality of the construction work. Syed showed great attention to detail and proactively checked in with us to ensure our satisfaction, offering helpful suggestions that improved the overall functionality and design of the extension. One of the most commendable aspects of working with Syed and his team was his commitment to communication. Always prompt in responding to queries, transparent about site developments, and kept us informed daily, which greatly eased the stress of the process. In summary, Brits Construction delivered a well-built extension, supported by excellent communication throughout. We would recommend them to others.”
Alex Gray
Review on Google
FAQ
Common Questions
Most single storey rear extensions fall under Permitted Development rights and do not require full planning permission. However, we always submit a Lawful Development Certificate application for peace of mind. Double storey extensions and properties in conservation areas may require full planning.
A typical single storey rear extension takes 8 to 12 weeks from start on site to completion. Larger or double storey extensions may take 12 to 16 weeks. We provide a detailed programme at contract stage and commit to a fixed completion date.
In London, good quality rear extensions typically work out at around £2,000 per m² for straightforward builds, rising with steelwork, drainage changes, rooflights, and higher specification finishes. Our fixed price quotes include everything from foundations to final decoration.
Most clients remain in their property during a rear extension build. We maintain a safe working area and keep dust disruption to a minimum. For larger projects or full renovations, temporary accommodation may be more comfortable.
Where we build rear extensions
Our team is based in Harrow and works across London and the Home Counties, including:
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Ready to start your project?
Fixed price quote within 5 working days. No obligation.