Physical address:
128 City Road, EC1V 2NX, London,UK
House Extension London | Rear & Side Extensions in North London
Looking for a professional house extension in London? Fixiz Ltd specialises in rear extensions, side extensions, and wraparound extensions throughout North London and the M25 area. Our expert team delivers high-quality house extensions that add valuable living space and increase your property value.
Why Choose Fixiz for Your House Extension London Project?
With over 25 years of experience in residential construction, Fixiz Ltd has completed multiple projects across London. We handle every aspect of your extension from initial design through to final completion, including all planning permissions, building regulations, and structural calculations.
Our House Extension Services Include:
Rear Extensions – The most popular choice for London homeowners, rear extensions typically add 3-6 metres to your ground floor, creating space for larger kitchens, open-plan living areas, or garden rooms with bi-fold doors.
Side Return Extensions – Perfect for Victorian and Edwardian terraced houses, side return extensions utilise the narrow alleyway beside your property to create wider, brighter kitchens and dining spaces.
Wraparound Extensions – Combining rear and side extensions for maximum space, wraparound extensions can add 30-50 square metres of additional floor space to your home.
Double Storey Extensions – For families needing significant extra space, double storey extensions provide additional bedrooms and bathrooms above a ground floor extension.
House Extension Costs London 2025:
Single storey rear extension (3m): From £35,000
Single storey rear extension (6m): From £55,000
Side return extension: From £30,000
Wraparound extension: From £65,000
Double storey extension: From £85,000
All prices include foundations, structure, roofing, windows, doors, plastering, electrics, and plumbing. Final costs depend on specification and finishes chosen.
Our House Extension Process:
- Free Consultation – We visit your property to discuss your requirements and provide initial advice on what’s achievable
- Design & Planning – Our architects create detailed plans and handle planning permission applications where required
- Building Regulations – We submit all necessary applications and ensure full compliance
- Construction – Our skilled team completes your extension to the highest standards
- Final Inspection – Building control sign-off and handover of your new space
Areas We Cover:
We provide house extension services throughout North London including Barnet, Enfield, Haringey, Islington, Camden, and surrounding areas within the M25.
Get Your Free House Extension Quote Today
Contact Fixiz Ltd for a free, no-obligation quote for your house extension project. Call us on 020 7971 1318 or fill out our online enquiry form. We’ll arrange a convenient time to visit your property and discuss your extension plans.
Explore our other property conversion services: loft conversion and garage conversion. We also offer comprehensive construction and renovation services across North London.
How Much Value Does a House Extension Add?
A house extension is one of the most effective ways to increase both your living space and property value. In London, a well-built rear or side extension can add between 15% and 25% to your property value. For an average North London property worth £550,000, that equates to an increase of £82,500 to £137,500, significantly more than the cost of the build.
The return on investment depends on the quality of the build, the design, and how well the extension integrates with your existing home. A kitchen-diner extension is particularly sought after by buyers and tends to deliver the highest return. All Fixiz extensions come with full Building Regulations sign-off and a completion certificate.
Trusted & Accredited Extension Specialists
Fixiz Ltd is fully registered, insured, and committed to delivering the highest construction standards.
✓Fully InsuredPublic Liability Insurance
⌂Building RegsFull Compliance Guaranteed
⚒Registered CompanyCo. No. 14561967
★Quality GuaranteedSkilled In-House Tradesmen
Real Results From Real Homeowners
Don’t just take our word for it — here’s what our clients say.
★★★★★
“Fixiz completed a rear extension of our four-bedroom home in London The team demonstrated excellent project management, strong attention to detail, and high-quality workmanship.”— Shalaka R., Finchley, N3
★★★★★
“Side return extension done on time and on budget. They handled planning permission, structural calculations, and Building Control seamlessly.”— Robert K., Enfield, N21
★★★★★
“Fantastic wraparound extension. The new open-plan living area has completely transformed how we use our home. Excellent attention to detail.”— Helen D., Haringey, N22
House Extension FAQs
Quick answers to the most common questions.
Do I need planning permission for a house extension?
Many single-storey rear extensions fall under Permitted Development and don’t require planning permission. Side extensions, two-storey, or Conservation Area properties typically need an application. Fixiz advises on your specific situation and handles all planning applications if needed.
How long does a house extension take to build?
A single-storey rear extension typically takes 8–12 weeks. A side return is usually 6–10 weeks. Two-storey and wraparound extensions can take 12–16 weeks. The design and planning phase adds 6–12 weeks before construction begins.
What is included in a Fixiz house extension?
Everything from initial design to completion: architectural drawings, structural calculations, planning applications, Building Regulations submission, groundworks, brickwork, roofing, windows, doors, electrics, plumbing, plastering, and decoration. One team, full accountability.
Do I need a Party Wall Agreement?
If your extension involves building on or near a shared boundary, you’ll need to serve a Party Wall Notice under the Party Wall Act 1996. This must be done before work begins. Fixiz guides you through the process and recommends experienced party wall surveyors.
What is the difference between a rear and side extension?
A rear extension adds space from the back of the house — ideal for larger kitchen-diners. A side return uses the narrow alley space beside the property, common in Victorian terraces. Both can be combined into a wraparound extension for maximum impact.
Get Your Free House Extension Quote Today
One of our extension specialists will be in touch within 24 hours to arrange your free, no-obligation site survey.
REQUEST FREE SURVEY & QUOTE