Extension Builders in Castelnau

Name: Extension Builder
Brand: MyBuilder
SKU: extension-builder
Rating: 4.2 (20 reviews)

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Some of our top rated extension builders in Castelnau

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J & M loft conversion ltd
Rating: 5 out of 5
Extension Builder in Castelnau
I’m a skilled landscaper with experience in designing and creating outdoor spaces that are both functional and visually appealing. From turfing and patios to fencing, planting, and garden maintenance, I take pride in delivering high-quality work with attention to detail. My goal is to transform outdoor areas into spaces homeowners can enjoy all year round. Reliable, hardworking, and customer-focused, I ensure every project is completed to the highest standard.
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Latest review:
Fencing- 26 Jun 2026
Very good, nice guy, good finished and cleaned, would recomment Jay.
Jozeph
Rating: 5 out of 5
Extension Builder in Castelnau
I am a professional and reliable tradesman who works to very high standards, these standards have helped me to build up an excellent reputation with regards to all work that I have carried out. Please request a quote through mybuilder.com for a free and honest estimate
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Latest review:
Handyman- 3 Oct 2015
Fast, efficient, friendly builder. Very skilful, quality work at a reasonable price. Couldn't be happier. Fully recommend Jozeph. Emma & Emanuel
Karan construction
Rating: 5 out of 5
Extension Builder in Castelnau
All construction work undertaken contact for any interior or exterior work
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Latest review:
Hard Flooring- 21 Aug 2025
Karan is absolutely brilliant,so polite,he laid my new laminated floor and done an amazing job I would highly recommend
Muhammad virk
Rating: 5 out of 5
Extension Builder in Castelnau
We undertake all kind of work. And our priority is to provide quality work
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Latest review:
Restoration & Refurbishment- 1 Mar 2023
Mohammed was very helpful and understanding I was very impressed about his work
Alpha Construction & Development Group Ltd
Rating: 5 out of 5
Extension Builder in Castelnau
Alpha Construction & Development Group Ltd offer bespoke service with a focus on the needs of our customers. We deliver one project at a time, without delays and stress-free. From small to big projects, we strive for the highest quality of work. We specialise in but are not limited to new builds, extensions, lofts conversions, structural works, roofing, plastering, rendering, painting and decorating, renovations, kitchen and bathroom fittings, pavings, brickwork, plumbing, full refurbishments.
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Latest review:
Bathroom Fitting- 25 Feb 2022
This was the best experience I have ever had with a team of builders. Aldo and Leo were polite, organised and their workmanship is of a very high standard. They replaced the bathroom in our rental flat, and it looks really smart. They also refurbished the kitchen, replacing flooring and decorated the whole flat. We have just shown it to an estate agent as we are planning to sell it and they were very impressed. Aldo was very helpful in making suggestions of small changes that would save us money and delivered the project on time and right on budget. Would recommend them and will certainly use them again.
HaliBuild
Rating: 4.7 out of 5
Extension Builder in Castelnau
We have been working as subcontractors for over 15 years now and decided it was time to branch out on our own, hence you find us on MyBuilder, We are eager to get some work done and some positive feedback to go along.
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Latest review:
Extensions- 26 May 2021
Ali Revani at Halibuild provided us with a quote which we accepted. 3 days before the job start date Ali Rezvani called and explained that they had under priced and they would want another £3000 to start the contract. Ali Rezvani then started the job but again admitted that they under priced the job and walked off the site several months into the project after the following major quality issues which needed to be addressed: Pouring the foundations in the wrong place, building the extension in the wrong place, building the roof incorrectly, installed roof steels in the incorrect position, built the extension rear wall too high, the plumbing to the boiler needed to be redone, all the plastering has had to be redone, skirtings needed to be redone, staircase had to be rebuilt. The list goes on and is 40+ points long. This has been a terrible experience and we face serious losses and a stressful dispute."
Apex Plan & Build LTD
Rating: 5 out of 5
Extension Builder in Castelnau
Apex Plan & Build is your trusted partner in turning vision into reality. Specializing in both domestic and commercial construction, we are dedicated to transforming houses into dream homes and businesses into efficient, modern spaces. With over 30 years of collective industry experience, our team ensures every project is completed to the highest standard, offering expertise in M&E works, including air source heat pumps and MVHR ventilation systems. We also bring cutting-edge innovation to your space with smart home automation solutions like Loxone and Control4, creating environments that are not only beautiful but also intelligent and energy-efficient. Apex Plan & Build is where your dream project is our top priority.
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Latest review:
Very professional and organised. My rear extension renovation was impeccable, thorough knowledge of building regulations with a variety of services to choose from really put me at ease. The venetian plaster feature wall has become the centrepiece of our home.
BL Carpentry
Rating: 5 out of 5
Extension Builder in Castelnau
Hello! My and my team are working on all kind of construction projects trough London. We've got 15 years of experience and many happy and returning clients.
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Latest review:
Multiple fitting out works, eg fitted cupboards, kitchen fitting. Top notch. Knowledgeable, fair, prompt. Would enlist his help again.
McBurnie Construction Ltd
Rating: 5 out of 5
Extension Builder in Castelnau
At McBurnie Construction, we specialise in high-quality brickwork, lime work, restorations, and groundwork across London and Bedfordshire. With over 20 years of industry experience and more than 1,000 successfully completed projects, we bring a wealth of knowledge and craftsmanship to every job. Our team is dedicated to delivering exceptional workmanship, whether working on modern developments or sensitive heritage restorations. We take pride in our attention to detail and our understanding of both traditional and contemporary building techniques. From initial estimating and detailed quotations to material advice and final delivery, we ensure a smooth and professional service throughout. Our expertise includes heritage brickwork, specialist pointing, and the use of lime mortars, ensuring that older properties retain their character and integrity while meeting modern standards. We work with a wide range of clients, including homeowners, estate agents, and property developers, and have built a strong reputation based on reliability, clear communication, and fair pricing. Our services include: Brickwork & Blockwork Restorations & Heritage Work Lime Work & Specialist Pointing New Builds Renovations Extensions Basement Reconstructions Groundworks No matter the size or complexity of the project, we are committed to delivering results that meet and exceed expectations.
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Latest review:
Bricklaying- 17 Mar 2024
Not sure if we could have been happier. McBurnie Construction LTD have been efficient, absolutely professional and literally went above and beyond what was expected,. We will definitely be using their services in the future. Awesome job Leron & Georgia! RJ & PG
Done By Tom Ltd
Rating: 5 out of 5
Extension Builder in Castelnau
Welcome to Done by Tom – we offer a completely bespoke design and build service for the London private sector. If you’re looking for clever, stunning and energy-efficient construction as well as interior design, we are it. At Done by Tom, we’ve come up with a unique success formula when it comes to memorable design and construction: combining the interior design, architecture and construction process into one seamless dream to deliver according to our clients vision.
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Latest review:
Fireplaces & Flues- 13 Nov 2017
i was so so happy with the service completed by done by tom. I had a really urgent last minute job and they were able to complete all the work to a really high standard and with a great price. I would trust them to do any building work in my house and am happy to have found a trusted builder for future works. Would recommend to anyone
BLUELIME CONVERSIONS LTD
Rating: 4.7 out of 5
Extension Builder in Castelnau
Bluelime is an established planning, design and construction company providing professional property services across London and the surrounding areas. Established in 2007, we have nearly two decades of experience helping homeowners successfully extend, renovate and transform their properties. Our services include architectural design, planning applications, interior design, structural engineering, building regulations, project management and construction. Whether you require assistance with one individual stage or a complete design-and-build service, we provide honest advice, creative solutions and a clear, professionally managed approach from the initial consultation through to completion. We have a strong track record of planning approvals and successfully completed projects. We have also been active on MyBuilder since 2012 and hold a 4.7 out of 5 customer rating, reflecting our long-standing commitment to quality, reliability and customer service. We offer a free initial consultation to discuss your property, understand your requirements and advise on the best way to move your project forward.
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Latest review:
Extensions- 8 Oct 2018
Alton and his team at Bluelime have been incredibly helpful and enthusiastic throughout our design and planning process. From the start, Alton took his time to understand our needs and propose several cost-effective ways to improve my home and create more space for my growing family. The design process was completed efficiently and submitted for planning permission, which was granted without a problem. Since then, his team have continued to be helpful and communicative despite my need to delay to the building works due to unfortunate complications with my freeholder.
Clars Build Ltd
Rating: 5 out of 5
Extension Builder in Castelnau
In collaboration with Trevi Home Ltd, a Surrey-based luxury kitchen, bathroom, and tile specialist, Clars Build Ltd is your top choice for renovation projects. Our skilled team, led by a 25-year-experienced Civil Engineer, offers: - Kitchen and Bathroom Design, Renovation, and Refurbishment - Loft Conversions and Extensions - Comprehensive Property Renovations Contact us today to create a more beautiful and functional home.
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Latest review:
1. Installation of new bathroom 2. Entrance hall, porch and living room plastering, painting, decorating and floor tiling 3. Electric work Laith’s team is hardworking, courteous and very skilled. Extremely pleased with the quality of work. The interior of the house has been transformed by the work and looks really great. Very pleased
Complete Construction london
Rating: 5 out of 5
Extension Builder in Castelnau
At Complete Construction we have a complete team to undertake all building and renovation works.We have been trading over 12 years,and forever growing.Priding ourselves on reputation and reviews and can offer plenty of references from recent clients.Having been known to have the team you want on your project,we are now being prided on our unbelievable Painting and decorating team
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Latest review:
Restoration & Refurbishment- 16 Jun 2023
Amazing job by Ross and his team! They're easy to deal with and the job was completed on time and to budget :) Will definitely use again! Thank you so much!
JM Building Service
Rating: 4.7 out of 5
Extension Builder in Castelnau
Hi my name is Joe from JM Building Service and I would like the opportunity to come and have a look at any works you require my services for. I look forward to meeting you. Thank you.
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Latest review:
Bathroom Fitting- 14 Mar 2025
My previous bathroom fitters did a very bad job with the bathroom and cloakroom toilet and left it unfinished. I am so glad I went with JM Building service as Joe and Martin completely transformed both rooms. They rectified the previous fitters errors and completed the rooms. Joe didn’t just rush through the job to get it done quickly—he took his time, ensuring every detail was finished to a high standard. He worked meticulously, making adjustments until everything looked exactly as it should, rather than settling for ‘good enough.’ His dedication to quality and precision was evident throughout, and the end result speaks for itself. As well as being very good at what they do, they are friendly, reliable, trustworthy and hardworking. I have already booked them in for another job and requested a quote for another. I highly recommend JM Building services for their professionalism and craftsmanship.
ritz builders uk ltd
Rating: 5 out of 5
Extension Builder in Castelnau
Ritz Builders UK Ltd can take care of any property renovation or house extension, from complex double basement developments to a new builds. Our builders have worked on various type of properties across UK, giving them a new light and converting them into modern and contemporary living spaces. Our professional construction team, who come supported by a dedicated workforce, are well regarded by commercial and residential property developers.
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Latest review:
The builder was reliable and dependable. Work was neat and to taste .
London Builders & Decorators
Rating: 5 out of 5
Extension Builder in Castelnau
London Builders & Decorators has been operating since 2016 in London. We our general builders who carry out Extensions, Lofts and Full Renovations. Why not shortlist us and come visit one of our sites. We run 5-7 sites at once so there will be one nearby. We try to keep things simple so the customer knows what is being done. Building work should be explained and expectations should be managed. We are a Member of the Federation of Master Builders & Gas Safe Registered
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Latest review:
Tiling- 22 Mar 2018
very professional work, the team was very flexible, patient and helpful with me adding some ideas along the way. I am very happy with the results.

4.2

Top rated Extension Builders

Our Extension Builders in Castelnau, are rated 4.2 out of 5 based on 20 reviews from customers like you.

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What types of services are offered by local extension builders in Castelnau?

Building an extension is a major milestone for any home. It’s not just about adding extra space, it’s a big step that can transform how you live day to day, opening up new possibilities for comfort, lifestyle, and family needs.

This is why it’s so important to find the right extension builders in Castelnau for you. They can help with a variety of tasks and projects, including:

Extending your home with an extra room
Two+ storey extensions
Adding partition walls to create more rooms
Building annexes or external structures

To find the right extension builder near you, simply post your job on MyBuilder. Explain the type of help you’re looking for, and then home extension builders in Castelnau who are available and interested can respond to your post.

Browse profiles, read customer reviews and get quotes from your chosen Castelnau extension builders, all before you decide who to hire.

What are the hourly rates of extension builders in Castelnau?

Before getting started with your extension project, it’s important to have a clear budget in place. On average, extension builders in Castelnau will charge between £16 and £42 per hour.

Single-storey rear extensions cost between £20,000 and £60,000 depending on size and finish.
The cost of double-storey extensions, which add more space and value, can range from £100,000 to over £170,000.
Larger wrap-around extensions that combine multiple extension types can range from £40,000 to over £120,000.

The cost of an extension will vary depending on your property. For instance, extending in certain areas may require structural adjustments to ensure stability, which can increase your material and labour costs.

To get an accurate price for your home extension, request detailed quotes from several Castelnau extension builders near you on MyBuilder. This allows you to compare what each quote covers and how much your Castelnau home extension project is likely to cost.

Find extension builders in Castelnau with MyBuilder

Hiring the right extension builder in Castelnau with MyBuilder couldn’t be easier. Just follow these simple steps:

Step 1: Post your extension project on MyBuilder

Whether you’re planning a single-storey extension, a loft conversion, or adding a new room, post your job on MyBuilder to find local Castelnau extension builders. Once your job is live, we’ll share it with home extension builders in Castelnau who can express their interest.

Step 2: Compare different extension builders in Castelnau

When you start receiving interest, review profiles of local Castelnau extension builders, check their previous work, and read real customer reviews. Ask about timelines, materials, and request detailed quotes.

Step 3: Hire Castelnau extension builders with confidence

After gathering all the information and quotes from your chosen home extension builders in Castelnau, compare their experience, guarantees, and costs before choosing who to hire.

You’ll also have confidence knowing that every tradesperson on MyBuilder is verified through several checks, including:

ID verification: When a tradesperson joins MyBuilder, we ask for a valid ID, such as a passport, ID card, or eIDAS certificate.
Company verification: For tradespeople operating under a company, we make sure every tradesperson has a registered business.

Did you know? Our continuous monitoring and complaints process ensures that tradespeople who don’t meet our standards are promptly removed from MyBuilder’s platform.

Castelnau extension builders are ready to help. Use MyBuilder today to find the right professional for your home extension.

What to ask a Castelnau extension builder before hiring?

Before hiring an extension builder in Castelnau or extension building company in Castelnau, ask a few key questions to make sure you’re choosing the right professional for your home extension project.

What qualifications and experience do you have as an extension builder in Castelnau?

An extension builder in Castelnau should have a strong track record with similar projects and relevant building qualifications or trade memberships, such as the Federation of Master Builders (FMB) or TrustMark.

Will my home extension meet all building regulations and planning requirements?

Your Castelnau extension builder should ensure the project complies with Building Regulations and, where necessary, handle or assist with planning permissions. Ask how they manage building control inspections and what documentation you’ll receive once the project is complete.

What experience do you have with similar extensions in Castelnau?

Ask to see examples of their previous work, or view examples of their work on MyBuilder. Ideally projects similar to yours in scale and design. This helps you assess the Castelnau extension builder’s ability to deliver a result that meets your expectations.

How long will the extension take to complete?

Extension project timelines can vary depending on size, complexity, and weather. A typical single-storey extension might take around 8 - 12 weeks. Request a detailed schedule so you know what to expect and when key milestones will be reached.

Do you offer a guarantee for your work? Most Castelnau extension builders offer a guarantee or warranty on their work, often between 1 and 10 years depending on the project and materials used. This gives you assurance that any issues will be resolved after completion.

If you still have questions about the professional you are looking to hire, we have a full detailed guide on hiring the right builder here.

FAQ: Common questions about home extensions in Castelnau

Can an extension builder in Castelnau help with planning permission?

Yes, many extension builders in Castelnau can guide you through the planning process. They can help prepare drawings, advise on local requirements, and liaise with your local council to ensure your project meets all necessary regulations.

Can an extension builder in Castelnau handle everything from design to construction?

Many Castelnau extension builders offer full design-and-build services, managing both the architectural planning and construction stages. Ask your builder whether they can provide a complete package or if you’ll need to hire an architect or designer separately.

Will an extension builder in Castelnau help with materials and finishes?

Yes, most extension builders in Castelnau can source materials and offer advice on finishes that suit your design and budget. You can also choose to supply certain materials yourself, just make sure this is agreed upon before work starts.