Extension Builders in St James

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 St James

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WORKSHOP & STUDIO - BAKKER LTD
Rating: 4.8 out of 5
Extension Builder in St James
Sole Trader since 2005, now a Limited Company since 2019. We Design-and-Build projects from Conversions, Extensions and New-build to Retail, Interiors, and Installations, and specialise in Carpentry, Cabinetry, Mobile Objects and Prototypes. We are architects/designers who also make/build, and carpenters/craftsmen who also design. We deal in anything bespoke, non-ordinary, at times with high or special demands. No project is too complicated or too simple. Get in touch for a free Quotation.
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Latest review:
Joinery & Cabinet Making- 1 Dec 2025
Extremely skilled and thoughtful to client
J&D
Rating: 5 out of 5
Extension Builder in St James
My name is Jacek i have been working as a builder for 15 years in UK I working with a team and we are good at Extensions Refurbishment Kitchens Bathrooms Rendering Plastering Painting
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Latest review:
Plastering- 24 Nov 2019
In the middle of finishing our kitchen job. His plastering has been excellent. Waiting now for a paint finish. Very punctual, honest and thorough with his job. I am very pleased we hired Jacek and will definitely be hiring him in the future. Thank you Jacek.
Dream Home Builder
Rating: 5 out of 5
Extension Builder in St James
My name is Leandro, I have 20 years of experience in construction industry in Europe and here in UK for 10. I don't mind in taking small handyman work or a full refurbishment of your house with a competitive price and high standard in quality and will be more than happy in help you with the maintenance of your home. We have worked in diverses range of projects applying skill and quality in every work. Thanks to read this small introduction.
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Latest review:
Tiling- 3 May 2019
Excellent communication from Leandro. He's a really tidy worker and has done a great job installing a splashback in our kitchen - would wholeheartedly recommend him to anyone
AVOTERG Ltd
Rating: 5 out of 5
Extension Builder in St James
Our aim is to help clients achieve their objective on time and budget and to the highest standard. We value the good communication with the clients, and try to have as much information as possible with regards to how their project must look when completed.
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Latest review:
The job was a complete refurbishment of a one bed flat, including rewiring and re-plumbing. We would recommend Al and his team without any hesitation. From the very beginning and all the way to completion, we felt very lucky and fortunate to hire them. We found them to be very hardworking, conscientious and professional. The job was a difficult and complex one, but the team still completed within time and within budget. Al's advice made the whole process easier and we found him to be very trustworthy and honest. The end result was better than we originally hoped for and was done to a high standard.
DS Developments
Rating: 5 out of 5
Extension Builder in St James
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.
JED BUILDERS LTD
Rating: 5 out of 5
Extension Builder in St James
A limited company established in 2016. More that 8 years experience in construction business. We undertake all building works, big or small, managing and looking after project so the client can have the best results possible.
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Latest review:
Kitchen Fitting- 14 Dec 2018
Very lovely and professional and clean. Very prompt/punctual and worked efficiently , will be using them again to do more work in my property. Definitely with recommend them to anyone ! 10/10 from me ! Good service delivery
BSM Interior Ltd
Rating: 4.9 out of 5
Extension Builder in St James
Your search for qualified and skilled builders ends here. Made Construction Simple is a team of licensed and insured specialists builders in London with over one decades of combined experience. From extensive loft conversion, extension,refurbishments to bathroom and kitchen renovations, we offer a wide range of services. You can rest assured that we have the expertise to efficiently handle your construction project. Good and dependable work isn’t possible without the necessary qualifications. Every professional on our team is qualified and highly experienced. We undertake all aspects of planning, building and construction services according to the highest standards of workmanship. We prioritise quality, safety and consistency at every step of the way. Our services are compliant with local authority laws and government regulations. We pride ourselves on our exceptional attention to detail. In addition to superior functionality and durability, we don’t forget about how the final result looks. We strive to deliver the best of structural integrity and aesthetics.   Our professional builders go above and beyond to earn your trust. We are dedicated to starting and completing jobs on time for 100% customer satisfaction. If there are any unforeseen delays, you will be promptly informed and kept in the loop. We also ensure that every project is within the specified budget.
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Latest review:
Carpentry- 26 Aug 2025
Great experience with Bled. Would recommend!
A J Keating
Rating: 5 out of 5
Extension Builder in St James
Hello we are a family firm based in north London. With more than15 years experience doing mostly exterior work. We enjoy difficult jobs and like a problem to be solved. Retaining walls, drainage, foundations are our bread an butter.We pride ourselves on a great job at a fair price.
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Latest review:
Groundwork & Foundations- 30 Aug 2022
Axel & his team have done a huge amount of work for us through 2022. They started by building the foundations, and then also built the block walls and the structure for the roof. They also constructed an entire extra timber framed shed. After more than four months of working for me constantly I can say that I'm very happy with the quality and speed of Axel's work. He has worked through all the work we have given him, and all the extra issues that came up, with a pragmatic and competent approach. The site today is unrecognisable from when he arrived (he also removed several tonnes of soil for us etc), and I would hire him again without reservation.
MYCO Contractors Limited
Rating: 5 out of 5
Extension Builder in St James
I am an experienced and fully insured builder. On average I and my team build and renovate 5 extensions per year. Our current or old clients are always ready to share positive feedback about our work. We work off the ready plans which are usually prepared by the clients themselves and approved by the local authority. As of now (30/03/2023) my availability to start the new project is late April or early May. Please get in touch and I will be happy to assist.
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Latest review:
Extensions- 4 Aug 2020
On a cold November evening, Tony and his team turned up to provide a quote and within a week this was received. The quoted price came in the middle of the pile, which was a good start and aligned closely to the ballpark figure I'd received from a friend who was also in the trade. We then visited a site they were finishing off, and Tony had the confidence to ask us to speak to the client without him there and they gave us the confidence to proceed. They started in January 2020 and rapidly moved through the works and engaged closely with my architect, Structural engineer and building control and proceeded based on their recommendations strictly. We lived in the property as build progressed and the team ensured that the site was secure every evening and we were safe. As COVID-19 hit and we went into Lockdown, the team continued to come and work (we were separated from them as the house was boarded up) and the only challenge was getting supplies. Tony scoured all over London, picking up items as best as he could and work continued. Once they'd broken through into the old part of the house they continued to progress rapidly and showed utter professionalism. The team lead's attention to detail is impressive, and he gave great recommendations on what would be the right approach when we were laying out features such as window sizing and lighting. The standard of work is excellent and I would highly recommend them.
Supra london Ltd
Rating: 5 out of 5
Extension Builder in St James
Polar Build is a family run business specialising in enhancing and extending residential properties to create your dream space. Our philosophy is deeply rooted in our unwavering commitment to creating spaces that enrich lives. We believe that every project is an opportunity to transform not just physical structures but also the way people experience and interact with their surroundings. We have our own showroom, contact us to arrange a visit to discuss what we can offer you
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Latest review:
Polar Build did a fantastic job on our bathroom! From planning to completion, they were professional, efficient, and tidy. They offered helpful design advice, and the quality of work—from plumbing to tiling—was top-notch. Every detail was carefully finished, and they made sure we were satisfied throughout. Highly recommend Polar Build for any bathroom project!
Clarke's Design & Build Limited
Rating: 5 out of 5
Extension Builder in St James
Flawless Finishes - look right here! Clarke's Design and Build are general contractors based in London, serving both the London and surrounding areas of the United Kingdom. Clarke's Design and Build focuses on tailor made home design, residential / commercial renovations and aim to use sustainable, environmentally friendly resources. We specialise in design, extensions, interior/exterior upgrades and aspire to turn challenges into solutions, plans into useful creative spaces.
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Latest review:
Carpentry- 22 May 2024
Great work from Leslie! On time, friendly, accommodating of all my questions and paid attention to all the details. Thank you Leslie.
Builders Are Us Ltd
Rating: 5 out of 5
Extension Builder in St James
With over 10 years’ experience in Loft Conversions, Extensions and Refurbishments, BuildersRUs offer the complete home service. Our dedicated team will help you transform your home, managing all aspects of the process including design, planning, regulations and completed build to the highest specifications. Let us realise your home’s potential, creating your ideal master bedroom, a kid’s gaming room, a quiet home office, or that dream kitchen. Call us today for great work at great prices.
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Latest review:
Bili did a amazing job. He and he's team has been extremely helpful and very professional. Bili listened, made good suggestions, clean and always on time. They finished the job perfectly and on schedule. It was pleasure working with Bili and his team and I would recommend them without hesitation.
Z&V PROPERTIES LIMITED
Rating: 5 out of 5
Extension Builder in St James
I have been working in this industry for 30 years. I have moved to London just about 8years ago. I`v been working as carpenter, builder site and rebuild house is out side and inside as well. Because my English language is not the best i have my little helper my son. Also he is working with me as well. He can take part in the same jobs as me .
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Latest review:
Carpentry- 2 Apr 2025
Zoltan did a great job of fitting my fire doors.
Nil building company ltd
Rating: 4.6 out of 5
Extension Builder in St James
Good to Know Verified professionals with years of industry experience Offers warranty on services Registered at Companies About Us At Nil Building Company Ltd, we specialize in delivering high-quality building services with a focus on 100% customer satisfaction. Over the years, our commitment to excellence and attention to detail have earned us a solid reputation, with most of our growth driven by customer recommendations. Our Services We offer a wide range of services, including: Full house refurbishment and extensions Bathroom design and installations Bathroom refurbishment Kitchen makeovers Emergency plumbing services Leak detection with advanced detectors Painting and decorating Wall and floor work Demolition work Electrical work Plumbing Carpentry New flooring installation Why Choose Us? Experienced Team: With many years in the industry, we ensure top-notch craftsmanship. Customer-Centric Vision: Our efficient and friendly service is designed to exceed your expectations. Reliable and Professional: From small fixes to large-scale projects, we handle every job with care and expertise. Contact Us For inquiries or to request a quote, get in touch with us today!
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Latest review:
Plumbing- 21 Sep 2025
The initial quotation for work was to fit a kitchen pipework for an island, however we decided to use Nil Building Company for our new home renovation which included electrical, plumbing, plastering, repair and painting work. Avash and his team have been great! They were hired for our new home renovation and did an amazing job. They were on time, tidy, provided professional advice and worked long hours to ensure the project was completed within time. The after service has been great too as they’ve returned to rectify any small nagging issues promptly, we really appreciate their hard work and dedication with the hope to use them again in future. I would highly recommend them!
Samz Construction Services ltd
Rating: 5 out of 5
Extension Builder in St James
We are a small construction firm aiming to provide high quality work. We do new built 'conversion, loft and extension, Refurbishment and all kind of building works. We can manage the building job from start to finish and help the clients with planning, party wall and structural drawings.
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Latest review:
Extensions- 4 Dec 2023
Happy with the quality of work and team was very friendly, everyday leaving the house livable for me and my wife while work was ongoing. Sohail offered good advice throughout the project and ended with shell completed after 8 weeks. Definitely reccomend getting a digger for excavation as we started building walls after 6 days, very fast! There were some minor delays as there are multiple projects going on in parallel, fitting in with timelines which is understandable as the team is very experienced and in high demand. Snag fixes were done promptly and all work signed off with building control. I would happily work with Sohail & team again, they have left the job with another satisfied customer - I think they turned out to be the best people to do the job, highly reccomend!
LLOCKBUILDING
Rating: 4.9 out of 5
Extension Builder in St James
"PUTTING THE TRUST AND RELIABILITY BACK INTO BUILDING" At Lock Building London, we specialise in helping you grow your vision by creating the dream home you've always imagined. We understand that your home is a reflection of your aspirations and lifestyle. Our team of skilled craftsmen will turn your ideas into reality, expanding your vision one brick at a time. From innovative designs to quality craftsmanship, we ensure that your home improvement project aligns perfectly with your vision and lifestyle. With our expertise, your dream home will not only meet but exceed your expectations, allowing your vision to flourish and your dreams to come to life
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Latest review:
Conversions - General- 15 Apr 2026
Luke and Diti are both amazing guys for this project. Honestly speaking they aren't the cheapest quote, but they are definitely beyond expectations. Luke was the only builder who gave a full transparent quote on each item and what was needed for the conversion. Really quick work and good planning because I have 2 cats and they did everything with enough people onsite to minimise the time. Speaking of work, it is good, we kept in communication and they were always happy to explain and adjust slightly according to my concern/question. Leave this comment after the work has been done for few months and everything is solid.

4.2

Top rated Extension Builders

Our Extension Builders in St James, 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 St James?

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 St James 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 St James who are available and interested can respond to your post.

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

What are the hourly rates of extension builders in St James?

Before getting started with your extension project, it’s important to have a clear budget in place. On average, extension builders in St James 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 St James extension builders near you on MyBuilder. This allows you to compare what each quote covers and how much your St James home extension project is likely to cost.

Find extension builders in St James with MyBuilder

Hiring the right extension builder in St James 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 St James extension builders. Once your job is live, we’ll share it with home extension builders in St James who can express their interest.

Step 2: Compare different extension builders in St James

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

Step 3: Hire St James extension builders with confidence

After gathering all the information and quotes from your chosen home extension builders in St James, 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.

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

What to ask a St James extension builder before hiring?

Before hiring an extension builder in St James or extension building company in St James, 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 St James?

An extension builder in St James 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 St James 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 St James?

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 St James 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 St James 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 St James

Can an extension builder in St James help with planning permission?

Yes, many extension builders in St James 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 St James handle everything from design to construction?

Many St James 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 St James help with materials and finishes?

Yes, most extension builders in St James 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.