One team, one point of responsibility
We handle design, planning, structural input and construction under one roof. No gap between architect and builder for problems to fall into, and no being passed back and forth when something needs a decision.
Design and build extensions
House Extension Company London - Design & Build
One accountable team from first sketch to final handover. We design, plan and build rear, side return, wraparound and double-storey extensions across East, North and Central London with clear scope, transparent pricing and weekly updates so the project never runs away from you.
£10M insured10-year workmanship guarantee500+ projects delivered5-star rated on Google, Houzz and MyBuilderBest of Houzz winner
5 star rated and award winning renovation company
Why choose Better Homes
Why London homeowners choose us to build their extension
Extending your home is one of the biggest investments you will make in it. The company you choose decides whether that feels like a smooth, well-managed project or a stressful one.
Pricing you can actually trust
Clear, detailed quotes before we start, with the scope written down so everyone knows what is included. Any change is priced and agreed with you first.
Weekly updates, start to finish
You will always know what happened last week, what is happening next, and where the budget stands. Most extension stress comes from silence on site, so visibility is built into the process.
Built to last, and guaranteed
Up to a 10-year workmanship guarantee and £10M insurance cover on every project. If something is not right, we come back and put it right.
Proven across London
500+ completed projects, 12+ years improving London homes, a 5-star-only record across Google, Houzz and MyBuilder, and Best of Houzz recognition.
Local specialists
We work across East, North and Central London and understand the planning quirks, conservation areas and party-wall realities that shape local extension projects.
Want to know if your extension is feasible and what it should realistically cost? Book a consultation and we will talk it through.
Extension types
Extension types we build
These are the common extension routes we deliver for London homes. For detailed cost, planning and design guidance, use the full guide linked from each route.
Rear extensions
We create brighter kitchen-dining and family spaces that connect the back of the house properly to the garden.
See full costs, planning and design detail in our complete 2026 House Extension GuideSide return extensions
A strong option for Victorian and Edwardian terraces where a narrow side passage can become valuable living space.
See full costs, planning and design detail in our complete 2026 House Extension GuideWraparound extensions
For homeowners who want a larger ground-floor transformation with more width, better flow and a more generous kitchen-living space.
See full costs, planning and design detail in our complete 2026 House Extension GuideDouble-storey extensions
A practical route when the brief needs meaningful extra space upstairs and downstairs, not just a bigger kitchen.
See full costs, planning and design detail in our complete 2026 House Extension GuideKitchen extensions
Designed around the way you cook, host and live, with the structure, services and finish planned together from the start.
See full costs, planning and design detail in our complete 2026 House Extension GuideIndicative investment
Planning-stage budget ranges
These are indicative planning-stage ranges only. They help you sense-check the order of investment before we assess your property, specification, access, approvals and finish level.
| Type | Typical budget | Planning note |
|---|---|---|
| Side return extension | £35,000 to £60,000 | Compact terrace route with meaningful ground-floor impact. |
| Single-storey rear extension | £50,000 to £95,000 | Common kitchen-dining and garden-connection project. |
| Wraparound extension | £75,000 to £140,000 | Larger ground-floor transformation with more structural work. |
| Kitchen extension with fit-out | £80,000 to £160,000 | Extension plus kitchen, services and finishing scope. |
| Double-storey extension | £100,000 to £200,000+ | More involved project adding space across two floors. |
For the full cost breakdown, per-square-metre rates, hidden costs and VAT, read our House Extension Cost Guide for London 2026.
Want a personalised range for your project? Use our extension cost calculator for a low/expected/high budget in two minutes.
Proof
Real extension projects
The best reassurance is seeing finished work in real London homes: the layout, the finish, the communication and the kind of problems a strong team knows how to prevent.
Rear extension + full renovationN19, North London
Rear extension and whole-home transformation in N19
A calmer layout, better natural light and a connected kitchen-living space that made the whole home work properly together.
“The team managed the project with clarity and delivered a finish that feels premium in every room.”
N19 Homeowner
Client testimonial
Side return extensionE7, East London
Side return kitchen extension in E7
A narrow galley layout became a brighter, more usable family kitchen with a stronger connection to the garden.
“The extension has transformed how we use the house day to day and the finish feels genuinely premium.”
E7 Homeowner
Client testimonial
Extension + renovationN8, North London
Kitchen extension and renovation in N8
A structural extension project that created a larger, brighter and more sociable kitchen-living zone.
“The build was organised, communication was clear, and the transformation feels substantial.”
N8 Homeowner
Client testimonial
Our process
A managed route from feasibility to handover
We keep the commercial risks visible: scope, planning, structure, sequencing, budget and communication. That is what stops an extension becoming a stressful guessing game.
Step 1
Feasibility
We pressure-test the property, planning route, likely constraints and budget before drawings gather momentum.
Step 2
Design
The extension is planned around light, flow, storage, structure and how you actually want to live in the space.
Step 3
Approvals
Planning, permitted development, building regulations, structural input and party-wall steps are coordinated before site starts.
Step 4
Build with visibility
Once work begins, you get weekly updates on progress, decisions, programme and budget so the project stays legible.
Guarantees that protect the work after handover
When you invest heavily in your home, you should know what happens after the builders leave. Our workmanship guarantees are there to give you clear protection and peace of mind.
10 years
Extension and loft conversion guarantee
2 years
Bathroom fitting and renovation guarantee
2 years
Kitchen fitting and renovation guarantee
1 year
Painting and decorating guarantee
Want the full guarantee breakdown?
Read it hereAreas we serve
Extension builders across Central, North, North East and selected West London
We focus on established London neighbourhoods where space, planning context, party-wall matters and access logistics need proper early handling. Our core patch runs from Central London and Westminster through Camden, Islington and North London, across to North East London and selected nearby west London areas for the right project.
Central and selected West London
For larger design-and-build projects in central boroughs and established prime neighbourhoods.
Central London
Westminster
Marylebone
Mayfair
Fitzrovia
Bloomsbury
Primrose Hill
St John's Wood
Maida Vale
Notting Hill
Kensington
North and North West London
Period homes, family houses and premium extension projects across the north London corridor.
Camden
Hampstead
Highgate
Crouch End
Muswell Hill
Finchley
East Finchley
Barnet
Golders Green
Islington
Canonbury
N8
N16
N19
North East and East London
Our strongest local patch, with deep experience in terraces, side returns and family-home extensions.
Hackney
Stoke Newington
Clapton
Dalston
Walthamstow
Leytonstone
Wanstead
Woodford
South Woodford
Chingford
Loughton
Chigwell
E4
E7
E17
Common postcodes
A quick guide to areas we regularly assess for extension work.
E4E7E17N8N16N19NW1NW3NW8W1W2W9
FAQ
House extension company questions
Practical answers for homeowners choosing who to hire, what is included and how the process works.
How do I choose a house extension company in London?
Look for a single accountable team that covers design, planning and build, so responsibility never falls between an architect and a separate contractor. Ask for a written, itemised scope and quote rather than a rough estimate, check that workmanship is genuinely guaranteed and the company is properly insured, and look at verified reviews and real completed projects in your area. At Better Homes you get all of that as standard: design-and-build delivery, transparent fixed-scope pricing, a 10-year workmanship guarantee, £10M insurance, and a 5-star-only review record across Google, Houzz and MyBuilder.
Do you handle the design and planning, or only the building?
Both. We take your project from the first feasibility conversation through concept design, planning or permitted-development applications, structural engineering and building regulations, and then the build itself, all managed by one team. That means you do not have to coordinate a separate architect, engineer and builder, and there is no finger-pointing if something needs resolving.
How much does it cost to hire a design-and-build extension company in London?
Most London extensions fall between roughly £35,000 for a side return and £200,000+ for a large double-storey project, depending on type, specification and borough. Because we include design within the overall project rather than charging a separate architect fee, the all-in number is often more competitive than it first looks. For a full breakdown, see our complete House Extension Cost Guide for London 2026.
Will my extension need planning permission?
Many single-storey rear and side return extensions qualify for permitted development and do not need a full planning application, while wraparound, double-storey and larger schemes usually do, and conservation areas or Article 4 directions change the picture. We assess this for your specific property at the feasibility stage so there are no surprises. Our 2026 House Extension Guide explains the rules in full.
Are you insured and is the work guaranteed?
Yes. Every project carries up to £10M insurance cover and a workmanship guarantee of up to 10 years. If a covered issue appears after completion, we come back and fix it. You will also receive the documentation, building control sign-off and certificates, that you need if you ever sell.
Which areas of London do you cover?
We work across Central London, Westminster, Camden, North London, North East London and selected nearby West London neighbourhoods, including Marylebone, Mayfair, Hampstead, Highgate, Crouch End, Muswell Hill, Finchley, Islington, Hackney, Walthamstow, Woodford, South Woodford, Chingford, Loughton and Chigwell. If you are nearby with the right project, get in touch and we will let you know if we can help.
How long does an extension take from first call to finished?
Construction itself is typically 8 to 24 weeks depending on the type: a side return is at the shorter end, a double-storey extension at the longer. Add design, approvals and any planning period before that, and most projects run around 5 to 10 months end to end. We give you a realistic timeline up front and weekly updates throughout, so you always know where things stand.
Ready to talk about your extension?
Get an honest view on what is feasible, what it may cost and the best route to get there
Tell us about your home and what you are hoping to achieve. We will give you a realistic view of the scope, budget and next steps with no pressure and no jargon.