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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Artesão Bespoke Carpentry
Rating: 5 out of 5
Extension Builder in Castelnau
Hi I’m a carpenter of 20 years, who has worked on various sized projects, from home refurbishments to big site new builds. I carry out all aspects of carpentry, to name a few: kitchen fitting, bespoke wardrobes, tv units, book cases, laying floors. I am a reliable, trust worthy individual, with my own transport, working in and around London. Happy to offer free quotations.
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Latest review:
Bathroom Fitting- 29 Apr 2023
Many thanks to Kris abd Kane on a job well done. Despite the very tight schedule, they completely refurbished our bathroom transforming it to a high-end (hotel standard) wet room. Kris's original quote was very competitive. There were extras, but these were very reasonable. Once the job was completed Kris actually came back to install 4 or 5 grab bars without additional cost. Kris, and Kane are both very easy to get on with; thoughtful and calm characters. I travelled abroad during the job; Kris contacted me regularly and responded promptly when I reached out to him. As with any job' there were glitches but Kris's solution focus approach ensured a good outcome. Hope to work with this company again.
Timeless finishes ltd
Rating: 5 out of 5
Extension Builder in Castelnau
With over 15 years in the construction industry, I have honed my expertise in managing both domestic and commercial projects. I thrive in high-pressure environments, where my skills in project management and quality assurance lead to successful, on-time project completions. I'm dedicated to sustainable practices and mentoring upcoming professionals in the field.Leading construction firm specializing in both residential and commercial projects. Managed multiple construction projects, overseeing budgets and ensuring projects were completed on time. Implemented quality control procedures that led to a 20% reduction in rework. Coordinated with subcontractors and suppliers to maintain project flow efficiently.Construction company focusing on residential buildings. Conducted site assessments and prepared reports on project feasibility. Supervised daily operations on site, ensuring adherence to safety standards. Fostered relationships with clients that resulted in repeat business
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Latest review:
Carpentry- 30 Dec 2025
Did the skirting across the whole house and the wood paint. Did a really good job! Would recommend.
Actonstruction
Rating: 4.1 out of 5
Extension Builder in Castelnau
Actonstruction as one of the premier builders in London carries out all aspects of building work including extensions, loft conversions, renovations, roofing, joinery and much more. We are focused on providing high-quality service and customer satisfaction.
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Latest review:
Extensions- 2 Mar 2017
I used the firm's services to build an extension. Darek himself seems to be a hardworking and reliable individual. Problem is - he surrounded himself by some not very professional people, including close family members, who make things much worse for him. The other problem was that most of his team members do not seem to have much loyalty to the firm and are ready to jump to a different job any time. We had a terrible delays with our project and some things we had to completely re-do using 3rd party services. If you can ensure Darek is 100% committed to your job - could be a good project, if not - please await problems (just like I had)...
ANACOND LTD
Rating: 5 out of 5
Extension Builder in Castelnau
Throughout the years in construction my father has gathered well balanced team with broad range of experience in every aspect of the job. After acquiring my engineering degree and some experience elsewhere, I re-joined my father once again to provide the service we are both proud of. Our background and experience in construction, design and engineering allows us to provide our clients with high quality service and ensure smooth work-flow of each project. Attention to detail is the key!
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Latest review:
Ground floor rear extension and Loft conversion. First and Second fix works including drainage, structural (block work, wood work and steel work) electrical, plumbing, plastering and tiling. All works completed to a very high standard, we found Arnolda's and his team very helpful, thoughtful and pro-active nothing seemed to be too much trouble for him, we are more than happy with AnA's Construction Developments.
Garry builders
Rating: 3 out of 5
Extension Builder in Castelnau
Hi I am garry I have 9 years experience in building work and I done lot of projects by myself in reasonable cost you can check profile pictures and contact us for quotes
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Latest review:
Painting & Decorating- 13 Jul 2023
Garry done nice work .
AVStructures
Rating: 5 out of 5
Extension Builder in Castelnau
A.V. Structures is a construction company working with top-rated contractors and providing services to private clients around London. Our highly experienced team of builders has excellent skills and knowledge gained delivering projects locally and abroad. We approach each building process following Environmental, Health, and Safety guidelines. All our quotes are free, and we will always try to get a quote to you within a week of us visiting your property.
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Latest review:
Demolition- 24 Nov 2021
We employed A.V Structures for the building of an external wall around our property, the removal of a garage and the installation of railings and gates. Throughout the 4 week programme we could not have been happier with their work. Arrival was prompt, their pace of work displayed energy and purpose. They were mindful of us and our neighbours and made sure the area was left clean and tidy at the end of each days work.in addition the workmen were courteous and kept us fully informed. Alex, the owner of the company, kept in close contact with us to assure himself of our satisfaction. He came on site at intervals to check that all was going according to plan. We therefore felt completely confident that quality and outcomes were important to him. Employing A.V Structures was a decision we were pleased to have made. We would use them again without hesitation and recommend them highly to anyone considering similar work.
BKFS LTD
Rating: 5 out of 5
Extension Builder in Castelnau
Work undertaking includes; Joinery, Kitchen and bathroom installation. Electrical NIC EIC approved contractor Gas safe Plastering, Painting, Tiling, Specialised in Bespoke wardrobes. Granite, Marble and Quartz Worktops. Wet room
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Latest review:
Tiling- 3 Jan 2025
Job completed in a very friendly and professional manner. Highly recommended. Once again, thank you Raghed!
Sorin Dobrila
Rating: 5 out of 5
Extension Builder in Castelnau
I've been in trade all my life, and most of the time engaged in: 1. Property Renovations and Remodellings – involving extensions, conversions, repairs and refurbishment works on residential properties. 2. Small/middle size commercial projects – involving repairs and refurbishment works for commercial clients.
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Latest review:
Extensions- 25 Aug 2021
Having had bad experiences in the past with other builders, this time we tried to do our homework properly before hiring someone. We couldn't have chosen a more competent and professional builder! We obviously asked around and had many quotes (some ridiculously expensive, others didn't even seem to understand what we wanted to do) but Sorin immediately impressed me with his detailed and fair quote, knowledge and lots of suggestions (he's the kind of guy that immediately gives you the impression that he knows what he's talking about). We encountered some issues during the works (which is to be expected if you didn't build the place yourself) but Sorin and his team did an amazing job and always gave us regular updates. End result? Work completed on time and a new construction that is exactly what we asked for (plus other things here and there that he kindly sorted while he was on site!)
Artsystem ESSEX Ltd
Rating: 5 out of 5
Extension Builder in Castelnau
We are providing high quality general building work like extension,loft conversion,bathrooms,kitchen fitting,plumbing ,completely refurbishment ..... We have ower 20years experiencies and our work is always hight quality. We can also help wiyh garden ,dryway,patio,fence ,roof,.......Dont hesitate ask me about help...
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Latest review:
Handyman- 23 Jan 2023
Would highly recommend....👍 He is a trades person you can trust. I was very happy with the work. He did what he said for the price we agreed upon. Carried out the job on time and worked with great enthusiasm. Seemed determined to solve all problems encountered and cleaned up at the conclusion of the job.Would highly recommend.I felt confident with them working on my property.
Ev max pro
Rating: 4.7 out of 5
Extension Builder in Castelnau
Reliable. Skilled. Trustworthy. *Qualified Electrician *kitchen fitter *Bathroom fitter *All General Repair *Extension and Pergola I take pride in delivering clean, precise, and high-quality work — on time, every time. Your home’s needs are in good hands. Whether it’s repairs, maintenance, or improvements, I’ve got the skills and dedication to handle it all. You don’t need to worry — just leave it to me. While you focus on your daily life, I’ll make sure everything at home runs smoothly. Trust me to get the job done right, with care and attention to every detail.
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Latest review:
Handyman- 18 Feb 2026
Excellent very amenable
H & F London Limited
No reviews yet
Extension Builder in Castelnau
H & F London is a specialist construction company based in Hertfordshire & West London. We’re known for providing groundwork solutions & new builds for a variety of clients across London and Hertfordshire.
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Garey Limited
Rating: 5 out of 5
Extension Builder in Castelnau
General building
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Latest review:
Very reliable and high quality of work.
B&K
Rating: 5 out of 5
Extension Builder in Castelnau
B.K. Building & Renovation is a family-run building and renovation business based in South Harrow. We provide reliable, high-quality work across extensions, brickwork, blockwork, plastering, painting and decorating, tiling, flooring and general property improvements. We take pride in clean workmanship, clear communication and attention to detail from start to finish. Whether it is an internal renovation, plastering and finishing work, brickwork, flooring or a larger building project, we aim to complete every job safely, neatly and to a professional standard. Customers choose us for our reliable service, respectful approach, tidy working habits and commitment to quality. We treat every property with care and work hard to deliver results our customers are happy to recommend.
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Latest review:
Benjamin and his team did a fantastic job on my property building a 6m by 6m Extension walls in only 2 days, it was done ahead of time and on budget. He was very conscientious and nothing was to much trouble. Done all the pictures of each step along the way needed for Building Control Guy. The quality and workmanship was first class and I would definitely recommend him for all types of building/refurbishment work.”
DS Developments
Rating: 5 out of 5
Extension Builder in Castelnau
My business is offering service in all the aspects of renovation, refurbishment and building work. My team is very reliable and respectful of our client's property. We work hard to make sure that all the work carried out is to the highest standards.
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Latest review:
Garden Maintenance- 17 Sep 2017
I hired DS Developments to completely landscape my small front garden. This involved clearing and levelling the area; moving and re-securing a bike shed; laying a patio and lawn; and a number of finishing touches. The area went from somewhat of an embarrassing eye-sore to an area of pride. One that several neighbours have already made compliments about. David provided a professional service from start to finish. His quote was more than I expected, but his knowledge and vision gave me the confidence to select his services. He provided a selection of options and stuck to budget; adapted well to new ideas/suggestions; and informed in advance where the cost would be impacted. He and his team also were as tidy and considerate as possible and I highly recommend their services.
Perfect House Building Service Ltd
Rating: 5 out of 5
Extension Builder in Castelnau
Company is open in 2015 . My experience in building and house refurbishment is 20 years . I finish building school in Poland when I spent 6 years on building side after school . In 2004 I move to England and I spend 11,5 years on building sides like self employed , 2,5 years I decide open my own ltd company . Work undertake by my company is house extension , lofts all types , full house/flats/offices refurbishment .
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Latest review:
Krzysztof has worked for me on many projects both residential and commercial. He is highly experienced across many skill sets, a master problem solver/ solution finder, trustworthy and reliable. I would recommend him as 1st choice on any project.
A S Builders
Rating: 5 out of 5
Extension Builder in Castelnau
We are a family run business in construction industry since 1990, initially started by my father and now his sons have joined the business and looking to revitalised the business through the use of up-to-date technology. We undertake all types of building work through our team of skilled labour from a small job up to New Build. Our most recent job was conversion of a detached property to 7 HMO's.
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Latest review:
Extensions- 29 Apr 2026
Heera, Jagthar and team was my first personal experience with builders. Let me tell you, it was a pleasure to have them do our porch and other renovations in the house. They are so courteous, hard working and provided a great service. Firstly, I had a comprehensively written quote breaking down all of the steps required. Heera then ensured to keep me in the loop of any developments/any changes of plan required, outlining the reasons why and options, making it easy to understand and work together to completion. Their finish was to a high quality and they would always go the extra step to ensure this. I highly recommend AS Builders for any job and will definitely use them again in the future, and would recommend to my friends and family also. If you are considering them, grab a free quote and go from there... That's what I did! Thank you AS Builders for our renovations!

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.