A home extension or full renovation is one of the biggest investments most Londoners ever make, so the company you choose matters more than any single design choice.
This is an honest, independently researched review of the eight best home extension and renovation companies in London for 2026.
No company paid to appear. We read published customer reviews across Trustpilot, Google, Houzz, Checkatrade, and Reviews.io, checked awards and accreditations, studied completed projects, and looked closely at how each company handles design, pricing, contracts, and payment protection. Where reviews are mixed, we say so.
The 8 Best Extension and Renovation Companies in London at a Glance
- Beams Renovation – best overall for managed renovations and extensions
- LCCL Construction – best extension and loft specialist
- NU Projects – best for super-prime whole-home projects
- APT Renovation – best value for extensions and basements
- DPA Home Renovations – best family-run extension team
- houseUP – best for prime full-house refurbishments
- GBG Building Services – best established luxury contractor
- Hill & Way – best for bespoke West London craftsmanship
Beams: Best Overall for Managed Renovations and Extensions
Beams is our number one because it turns the riskiest, most stressful part of any extension or renovation, choosing and paying a builder, into a controlled, protected process.
Rather than leaving you to source, vet, and pay a contractor yourself, Beams matches you with vetted London builders, fixes the price in writing, and holds your money securely until you sign off each stage.
Why Beams is our pick for a managed, low-risk renovation:
- Full scope under one contract: extensions, loft conversions, basements, kitchens, bathrooms, and full home renovations across North, South, East, and West London, with one builder, one contract, and one point of contact from design to final coat of paint.
- The strongest financial protection on this list: fixed-price contracts in writing, milestone payments held securely and released only on your sign-off, and a 12-month workmanship warranty with up to £10,000 of cover if a builder leaves the network.
- Genuinely vetted builders: every builder is visited in person, reference-checked, and inspected on recent work, with an average of 15 years of residential renovation experience. You meet up to three and compare detailed, like-for-like quotes before committing.
The product: a managed renovation service plus in-house interior design and 3D visualisation, so you can plan an extension or whole-home layout in 3D before a brick is laid. Your first design call is free, with further design support at £150 per hour.
How it works: set a budget with a quick quiz or an expert, meet up to three vetted builders who each quote like-for-like, then choose one and let Beams prepare the contracts and milestones so you stay in control throughout.
Case study focus: Beams handles everything from single-room extensions to full property transformations, with published customer reviews describing a calm, well-run process, including a Notting Hill client who praised the recommended contractor as “knowledgeable” and hard-working, and a Queen’s Park client who said Beams “removed all the stress”.
The stats, honestly: Beams holds a 4 out of 5 rating on Trustpilot from around 98 reviews, is a certified B Corp, and has featured in the Financial Times, The Times, The Telegraph and House & Garden. A minority of reviewers report coordination or timeline issues, so agree milestones and communication expectations upfront.
2. LCCL Construction: Best Extension and Loft Specialist
If your project is fundamentally about adding space, LCCL Construction is the specialist to beat, a North London design and build firm with more than 20 years of experience.
Why LCCL is our pick for extensions and lofts:
- The best-reviewed firm on this list: more than 200 verified reviews across Trustpilot, Google, Reviews.io and Houzz, with a combined 4.7 out of 5.
- Award-winning extensions: LABC Building Excellence Awards Regional Winner 2024 for Best Residential Extension in London.
- Single project manager model: one dedicated manager oversees your build from first drawing to final handover.
The product: full in-house design and build, covering architecture, planning, extensions, loft conversions, renovations, and new builds.
How it works: LCCL takes you from architectural drawings through planning to construction under one roof, so a single team is accountable end to end.
Case study focus: kitchen-diner extensions, side-return builds, and loft conversions, the exact project type its 2024 LABC award recognised.
3. NU Projects: Best for Super-prime Whole-Home Projects
NU Projects is the pick for high-value, design-led renovations and structural work in prime central London, backed by more than two decades of super-prime experience.
Why NU Projects is our pick for prime whole-home work:
- Super-prime specialist: full-scale renovations, structural reconfigurations, basements, and bespoke joinery in Chelsea, Kensington, Knightsbridge, Mayfair and Notting Hill.
- Award-winning design team: a multi-award-winning studio recognised for high-end interior architecture and finish quality.
- Disciplined delivery: a process built around programme control, cost clarity, and flawless craftsmanship.
The product: integrated architecture, interior design, and construction delivered by one leadership team.
How it works: NU Projects collaborates with private clients, architects, and designers from concept to completion, keeping design and build under a single team.
Case study focus: complex, design-led whole-home refurbishments and basement builds in prime postcodes.
4. APT Renovation: Best Value for Extensions and Basements
APT Renovation is a design and build company specialising in home extensions and renovations, frequently praised on price for space-adding projects.
Why APT is our pick for value extensions:
- Competitive pricing: several clients report excellent work at highly competitive prices.
- Extension and basement focus: kitchen extensions, basement conversions, full refurbishments, and new builds.
- Do your due diligence: reviews across Houzz and Birdeye are more mixed than others here, with some serious complaints alongside the praise.
The product: a design and build service handling both drawings and construction for extension-led projects.
How it works: APT takes on the design and the build together, aimed at homeowners investing in a substantial extension or basement.
Case study focus: budget-conscious rear and kitchen extensions and basement conversions. Check recent references and get everything in writing before committing.
5. DPA Home Renovations: Best Family-run Extension Team
DPA Home Renovations is a family-run construction company with more than 20 years of experience and outstanding independent review scores.
Why DPA is our pick for a personal, high-trust build:
- Top verified ratings: 5.0 out of 5 on Checkatrade from around 30 reviews, plus a 5.0 rating on Google.
- Extension capability: kitchen extensions, lofts, basements, full house renovations, and new builds.
- Personal service: reviews repeatedly praise communication and attention to detail from a hands-on team.
The product: a directly managed, family-run design and build service.
How it works: the DPA team manages your extension directly, working with architects where structural or planning work is involved.
Case study focus: extensions and full refurbishments in South London homes, with reviewers singling out consistent craftsmanship.
6. houseUP: Best for Prime Full-House Refurbishments
houseUP is a premium house renovation company with almost 10 years of experience, strong on full-house refurbishments in prime and period properties.
Why houseUP is our pick for prime refurbishments:
- Prime and period expertise: complete house renovations, layout reconfiguration, and high-end finishes in areas such as Belgravia, Highgate, and Kensington, including listed buildings.
- Professional endorsements: a 5.0 rating from 10 reviews on Top Rated Builders, with architects praising its work on Grade I listed and Conservation Area projects.
- Aftercare focus: clients highlight quick issue response and strong aftercare.
The product: an in-house design and build refurbishment service.
How it works: houseUP manages the whole refurbishment in-house with a single team, from planning through to finish.
Case study focus: full-house refurbishments of prime and listed homes. Some clients report costs rising above initial estimates, so pin down the quote in detail.
7. GBG Building Services: Best Established Luxury Contractor
GBG Building Services has operated since 2005 as a main contractor in London’s prime property refurbishment market.
Why GBG is our pick for high-specification homes:
- Two decades in prime property: bespoke renovations and high-end residential building across the capital.
- Award-recognised service: Best of Houzz Service winner three years running, and an Industry Partner of the British Institute of Interior Design.
- Backed workmanship: a minimum 12-month guarantee on completed work.
The product: a main-contractor service for luxury renovations and extensions.
How it works: GBG coordinates trades and delivers the build, often alongside your own architect or interior designer.
Case study focus: high-value refurbishments and extensions in prime homes.
8. Hill & Way: Best for Bespoke West London Craftsmanship
Hill & Way is a high-end residential contractor focused on London’s most prestigious postcodes, from Notting Hill and Kensington to Mayfair.
Why Hill & Way is our pick for prime West London finishing:
- Prime West London focus: luxury refurbishments and extensions across Kensington, Chelsea, and Notting Hill.
- Consistently strong feedback: positive reviews across platforms including Birdeye, with clients citing meticulous workmanship and on-time, on-budget delivery.
- Partnership approach: hands-on project management that clients describe as a genuine partnership.
The product: a contractor-led service with a dedicated project manager for bespoke, high-finish work.
How it works: a single project manager oversees your refurbishment or extension from start to finish.
Case study focus: detailed, craftsmanship-led refurbishments and extensions in prime West London.
How to Choose the Right Extension or Renovation Company in London
The best company for you is the one that matches your project type, protects your money, and has a review history you can actually verify.
Define your scope and a realistic budget first, then shortlist three companies whose completed projects resemble yours. Check that reviews are spread across independent platforms rather than only the company’s own site, and look for consistency across dozens of reviews rather than a handful of glowing ones.
Insist on a detailed, fixed written quote, confirm who your day-to-day contact will be, and make sure payments are tied to completed and approved stages rather than paid upfront. For extensions, also confirm who handles planning permission and building regulations.
Questions to Ask Before You Hire
- Can I see reviews and completed extensions or renovations similar to mine on independent platforms?
- Is the quote fixed and in writing, and what would trigger extra costs?
- How are payments structured, and are they released only when I approve each stage?
- Who is my single point of contact, and how often will we speak?
- What workmanship warranty or guarantee do you provide after completion?
- Do you handle design, planning permission, and building regulations in-house?
Frequently Asked Questions
Who is the best home extension and renovation company in London?
Based on our research, Beams is the best overall for a managed, low-risk renovation or extension in London for 2026, thanks to vetted builders, fixed pricing, secured milestone payments, and a 12-month workmanship warranty. For extensions and lofts specifically, LCCL Construction has the strongest verified review profile and a recent LABC award.
Is this ranking independent?
Yes. No company paid to appear. The order reflects our own research into verified reviews, awards, service range, and customer protections, and we have flagged mixed feedback where we found it.
How much does a home extension cost in London?
Extension and renovation costs in London vary significantly by size, specification, structural complexity, and location, so treat any figure as a broad range rather than a fixed price. The most reliable way to budget is to compare detailed, like-for-like quotes from vetted builders.
