Extension Builders in St James

Name: Extension Builder
Brand: MyBuilder
SKU: extension-builder
Rating: 4.2 (19 reviews)

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Some of our top rated extension builders in St James

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London Builders & Decorators
Rating: 5 out of 5
Extension Builder in St James
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.
Adam Favor
Rating: 4.8 out of 5
Extension Builder in St James
Our business was founded to offer clients the opportunity to bring a vision to life. As a design & build business we can take your dream home concept and turn it into reality. We will provide you with design plans for your projects and thorough project management. We also have the professional, experienced and quality tradesmen that are essential to complete the construction phase of the project.
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Latest review:
Plastering- 17 Jun 2024
Adam Favor and NOVA Design & Build are a nice bunch of guys and they are reliable/helpful. However, when it came to coving, architrave and flooring, acceptable standards were unfortunately not met. Other specialists had to be brought in to re-do around 20% of the job; namely certain sections of the cornice and door architrave. In the former, a few things were below standard including: 1) not joining the friezes in the correct places, 2) cutting inaccurately, 3) leaving gaps, 4) using silicon as a filler and adhesive. For the door architrave, the wood was misaligned and not glued/nailed properly. The flooring was not laid well because there are huge gaps at times; sometimes at 1 cm. Since the kitchen has been installed, it is too late to take up the floorboards again. The most dubious thing of all in this job was the quote received for decorating which was c. 15k for 47 m2. This included plastering repairs, but ultimately the job got done by someone else to a high standard at 7k.
VCKS
Rating: 5 out of 5
Extension Builder in St James
VCKS Professional service provided on time
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Latest review:
Tiling- 10 May 2025
Victor is excellent. Gave a competitive quote and stuck to it. Victor works quietly and thoroughly. The job was completed on time and to a high standard. I will use him again and I recommend him.
Cunningham Developments & Property services ltd
Rating: 4.8 out of 5
Extension Builder in St James
Cunningham Developments and Property Services Ltd is an innovative, family-run design, planning, and construction company with over 16 years of experience in architecture planning and construction. We specialize in providing comprehensive services that encompass every stage of the development process, from initial design concepts to project completion. At Cunningham Developments, we pride ourselves on our commitment and the willingness to achieve clientele satisfaction.
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Latest review:
CAD / Drawings- 11 Sep 2025
Justin was responsive and reliable in nudging the council. Got a greater scope approved, too
Livinroom Developers Ltd
Rating: 5 out of 5
Extension Builder in St James
Our expertise lies in project management of loft conversion and kitchen extension which is carefully coordinated to ensure a seamless and integrated package service from start to finish. Our role is to be the single point of responsibility taking the burden off the client. This includes managing what are often complex building processes from inception through to completion and hand over.
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Latest review:
I recently completed the building of an orangery extension (with skylight) to my semi-detached townhouse in NW London. The extension was to be used as a new kitchen while the existing kitchen converted to a living room. I awarded the contract of building the extension to Anthony and I was pleasantly impressed with the quality of work delivered. Anthony Project Managed the entire process from beginning to end and ensured that all my expectations were surpassed. His hands-on attitude to every detail of the work was quite reassuring. I am glad to say that Anthony and his team are very good professionals and they delivered the project on time and within budget, even going over and beyond the original scope of works in order to ensure that all my latter requests were addressed appropriately.
Envision Brickwork Ltd
Rating: 4 out of 5
Extension Builder in St James
Welcome to Envision Brickwork we aim to deliver high quality bespoke brickwork with over 8 years of experience in the domestic and commercial construction space.
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Latest review:
Bricklaying- 19 Nov 2025
Please avoid this company for many reasons. There work is absolutely shocking and the owner is incompetent and should be ashamed of himself how he left my job. I’ve tried to contact Elijah and he’s blocked me, he’s an absolute disgrace. I will put up pictures of his work so you can see how bad his work is.
Guildkey Builder
Rating: 4.9 out of 5
Extension Builder in St James
Welcome To GUILDKEY BUILDER's, We are a small company and specialise in: Loft conversions, Side and rear Extensions also double extensions and full refurbishments We also carry out small jobs such as kitchens fittings and bathroom fittings, developing properties into flats, We provide quality service to our customers. We want you to live in a better and secured Home
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Latest review:
Extensions- 31 Jul 2025
Absolutely incredible from start to finish! Professional, knowledgeable and easy to work with. Managed to think on his feet and fix unexpected problems, gave advice and was always polite and friendly! My house is completely transformed & I’ll definitely be using Kaiser again for the next house Reno!
UCSCONSTRUCTION & DAMPROOFING SERVICES
Rating: 5 out of 5
Extension Builder in St James
My work involves all aspects of construction, renovations, internal & external works & structural alterations. I have been in this industry for 25yrs+. Working along side me I have both architects & structural engineers which allows UCS CONSTRUCTION to offer a complete package within the team, We operate in most parts of the london areas. As the team head & owner of UCS we are fully qualified to offer all necessary gas/elec certification & operate with a £5m liability insurance cover.
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Latest review:
Kitchen Fitting- 31 May 2021
We were thrilled with the service from UCS Construction. Richard was efficient, considerate and professional throughout the planning and the execution of this job. He consulted us so we agreed on exactly what we wanted and went over and above to ensure it all went smoothly. We can’t recommend him highly enough...we are so pleased. Thank you Richard.
Balham construction Ltd
Rating: 5 out of 5
Extension Builder in St James
Balham construction are a London based refurbishment and construction company that offer a wide range of services from full Property refurbishment to extensions and loft conversions and everything in between
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Latest review:
Tom and the team completed a full renovation of my flat. This included refurbishment of my kitchen, bathroom and general redecoration. The team were extremely hardworking and punctual and no job was too difficult for them. I would highly recommend their services.
DC Brickwork
Rating: 5 out of 5
Extension Builder in St James
Dear Customers I am honest trustworthy reliable and hardworking and I have over 25 years experience in the industry.
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Latest review:
Bricklaying- 29 Jun 2017
I would recommend Damian. Did a good job, good communication and was on site when he said he would be. Polite and friendly. I would be happy to use again.
adam lloyd construction ltd
Rating: 5 out of 5
Extension Builder in St James
At Adam Lloyd construction we specialise in high end refurbishments but we also undertake small works and maintenance from decorating to landscaping we have excellent tradesmen in-house
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Latest review:
This carpenter is a plywood maestro! My wardrobes are a testament to their craftsmanship – sturdy, stylish, and a definite upgrade from my previous cardboard chaos. Would highly recommend for a wardrobe transformation that's as solid as it is delightful. ⚒️👌 Top notch, class A stuff 👍🏻
JM Building Service
Rating: 4.7 out of 5
Extension Builder in St James
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.
YOB CONSTRUCTION LTD
Rating: 5 out of 5
Extension Builder in St James
At YOB Construction Ltd, we believe your home or business deserves the highest standard of workmanship. Based in North West London and proudly serving the surrounding areas, we specialise in a full range of building and renovation services, from kitchen and bathroom installations to bespoke carpentry, tiling, painting, decorating, and complete refurbishments and extensions. What sets us apart is our commitment to quality, reliability, and customer care. Every project, no matter the size, is managed with precision and attention to detail. We work closely with our clients to understand their vision, provide honest advice, and deliver results that not only meet expectations but exceed them. With years of experience and a team of skilled professionals, YOB Construction Ltd has built a reputation for trust, professionalism, and lasting results. We source only high-quality materials, maintain clear communication throughout the process, and ensure every job is completed on time and to the highest standard. Whether you’re refreshing a single room or transforming an entire property, you can rely on us to bring your ideas to life with skill, care, and dedication. Get in touch today for a free, no-obligation quote.
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Latest review:
Bathroom Fitting- 9 Nov 2025
Very good work. Alaa repared the tap in my bathroom and fixed a broken tile. The end result is excellent. I highly recommend.
NA
Rating: 5 out of 5
Extension Builder in St James
Skilled, tidy bricklayer. Highly competent in building, pointing and restoration. Garden walls, extensions, new builds, etc
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Latest review:
Jack built a brick buttress to structurally support my garden wall. Originally I was going to rebuild the entire wall, but Jack’s advice to build a buttress saved me a lot of money! The job was done quickly, affordably and to a high standard. Would highly recommend.
Alpha Construction & Development Group Ltd
Rating: 5 out of 5
Extension Builder in St James
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.
Mile Kresojevic
Rating: 5 out of 5
Extension Builder in St James
Hi, I am experienced self-employed carpenter with 10 years in various projects, working directly for clients while entrusted for their property. Good English, punctual, trustworthy and a reliable time keeper. Can provide references on request.
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Latest review:
Carpentry- 5 Dec 2017
Mile was prompt in supplying a quote and fitted us in within days. He was tidy in his work, pleasant to deal with and reasonable with his quote, we will use him again should we need any carpentry work.

4.2

Top rated Extension Builders

Our Extension Builders in St James, are rated 4.2 out of 5 based on 19 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.