Extension Builders in St James

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

Easily find verified St James Extension Builders. Just post your job to get quotes from MyBuilder's Extension Builders in St James.

Select a service

How it works

Post your job for free

Tell us about your job, and we’ll alert suitable tradespeople in your area. It’s simple and free.

Tradespeople respond

Once your job is posted, you’ll get responses from interested tradespeople through the website.

Review profiles and choose

Browse profiles, work history, and feedback, then choose who you wish to share your details with.

Some of our top rated extension builders in St James

3545 Results

Sort by:

SW Heating & Refurbishments Ltd
Rating: 5 out of 5
Extension Builder in St James
SW Heating & Refurbishments is a local refurbishment company specialising in complete property refurbishments, extensions and loft conversions, new heating systems and boilers. We take pride in all of our work and our aim is to provide you with a quality finish, tailored to your budget. With over 19 years experience, we have built up an extensive team of tradesmen allowing us to provide an outstanding service. We are fully insured and all our work is gas safe and NICEIC certified.
Get in touch
Latest review:
Conversions - General- 20 Mar 2024
Charlie & Richard did a great job. They visited my property to get an accurate quote. They let me visit another property they are developing which gave me confidence that they were more than capable of my job. They carried out the work quickly and to a high professional standard. Wouldn't hesitate to use them again.
Ev max pro
Rating: 4.7 out of 5
Extension Builder in St James
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.
Get in touch
Latest review:
Handyman- 18 Feb 2026
Excellent very amenable
SZG BUILDING LTD
Rating: 5 out of 5
Extension Builder in St James
18years of experience in the construction sector. I may only offer you quality services and nothing less, with SZG BUILDING LTD you will not have to worry about anything. I specialise in every stage of the construction process, right from the very beginning till the very end, in other words from FOUNDATION to DECORATION in the blink of an eye. I will be very pleased to show my previous work, it may be the final outcome or different stages of various projects. References may be provided.
Get in touch
Latest review:
Kitchen Fitting- 20 Jun 2019
Really pleased with Slawek and his team and would defiantly recommend them after seeing a professional kitchen fit job which they did for me. They went extra mile to resolve some design issues during the fit, kept the work area clean and tidy and behaved in friendly, polite manner. Nice, reliable team charging very reasonable prices.
Independent Building Services Ltd
Rating: 5 out of 5
Extension Builder in St James
We are an experienced construction company based in west acton. Quality work and reasonable prices, building maintenance, full renovation, extensions and loft conversions, design and advise plus much more . We will beat any prices and 100% customer satisfaction guaranteed.
Get in touch
Latest review:
Extensions- 9 Feb 2019
I had the pleasure of working with Habib on the renovation of my house. My review of his work during renovation: 1- He has done excellent job in rewiring the house. he segmented each floor and kitchen and put them on separate ring, he expanded consumer box for future growth as well as installing wired smoke and security alarms 2,3 - He fitted pipe and installed unvented cylinder system with water softener perfectly including multiple heating control zones which I can control each floor individually (I love it). 4- he built a beautiful and prefect extension in garden, he considered all building regulations such as structural integrity, fire safety, energy efficiency, damp proofing, ventilation and other key aspects that ensure a building is safe. In addition to above he has very good personality and he is approachable to discuss changes or add new tasks to job (unlike some builders whom don’t like it). Throughout the course of the renovation, Habib was a consummate professional. He was accurate in his initial assessment of the scale and cost of my project. Good work takes time to complete. Patience is required when you work with a perfectionist. Although my project took time to complete, I have a wonderful outcome and a work of art now. I can recommend him highly and without reservation. Thank you, Habib, At the end I would like to thank Jake for his part and hard-working during renovation of my house. Hamid
IDL Contractors Ltd
Rating: 5 out of 5
Extension Builder in St James
I am in the building industry for more than 20 years, nevertheless, my company was registered in 2017. Our team is specialized in doing extensions, house conversions and refurbishments.
Get in touch
Latest review:
I can't recommend IDL highly enough, Lubo and his team were efficient, on time and completed the work quickly with no fuss, plus they gave us a payment plan and time frame that suited us. Our garage conversion has transformed our house, it feels so open and light, thanks Lubo xx
UK Crown Developments Ltd
Rating: 5 out of 5
Extension Builder in St James
UK Crown has experience of design and build in all types of construction work in central, north and north west London for the last 20 years with exceptional quality finishing, friendly management and supervisors, design team, staff and sub contractors. The client will get benefit of FREE advise for architectural and structural ,mechanical and electrical, including party wall matter from our company and associates.( Subject to contract ) Terms and conditions
Get in touch
Latest review:
Total refurbishment and extensions and ongoing smaller works we required thereafter
E&E Plumbing and Construction LTD
Rating: 4.6 out of 5
Extension Builder in St James
About Us Based in London, our construction company proudly offers a comprehensive range of building and renovation services across the UK. With expertise spanning from minor renovations to major projects, we are committed to delivering high-quality craftsmanship and exceptional customer satisfaction. Our Services General Construction & New Builds: Turning your vision into reality through bespoke new build projects, tailored to your specifications and delivered with precision. - **Loft Conversions:** Maximize your property's potential with expertly crafted loft conversions, providing additional living space and increasing your home's value. - **Plumbing & Electrical Works:** Providing reliable and efficient plumbing and electrical installations, upgrades, and repairs to ensure safety and functionality. - **Housing Projects:** Specializing in house extensions, loft conversions, and structural modifications to enhance your living space. - **Roofing Solutions:** Expert roofing services including flat roof installations, repairs, and fiberglass coatings to protect your property. - **Window Installations:** Supplying and fitting modern bifold windows that enhance aesthetics and improve energy efficiency. - **Additional Services:** We also undertake a wide range of structural and decorative renovations, ensuring a seamless integration of new elements with existing structures. No matter the scale of your project, we are dedicated to delivering quality workmanship, on time and within budget. Contact us today for a consultation and let us bring your construction ideas to life. E&E Plumbing and Construction LTD
Get in touch
Latest review:
Plumbing- 15 May 2026
They were really fast to book in an appointment and communicated well. They also did a great job, exactly what we needed, and very friendly. Thank you!
shalom property development ltd
Rating: 5 out of 5
Extension Builder in St James
Shalom Property Development ltd is a small construction company based in the Croydon area. We specialize in property refurbishment, house extensions, loft conversions, garage conversions, etc. We also undertake projects like plastering, painting/decorating, electricity, plumbing, tiling, flooring(laminate, wood, bamboo), bricklaying.
Get in touch
Latest review:
Plastering- 6 May 2025
Amazing guys. Hardworking, tidy, professional. They worked in our house for 3 months and we were super happy with the work and everything. We invited them to do more work later on. 100% probably the most sincere and trustworthy builders we met. Only them. No one else from now on.
P&T Property renovation LTD
Rating: 5 out of 5
Extension Builder in St James
LND Development ltd was established by a Polish builder. As a business we pride ourselves to provide a very experienced, hard working, friendly and loyal workforce. We provide a professional and experienced service at very competitive rates.
Get in touch
Latest review:
Pawel and the team did a fantastic job. The bathroom looks superb and the whole team took time to finish the job to a very high standard. There was a narrow timeframe in which to do the work and this was met (despite more effort than first thought with respect to strengthening the floor). Pawel was easy to deal with and contacted me after the job to ensure everything ok. Highly recommended.
Dmytro Dochynets
Rating: 5 out of 5
Extension Builder in St James
Experienced bricklayer. Skilled in brickwork, garden walls, fences and repair jobs. Reliable, tidy and delivering quality work on time.
Get in touch
Latest review:
Bricklaying- 30 Oct 2025
Dmytro did fantastic job rebuilding garden wall in our landscaping project. Highly recommended
enrike
Rating: 4.9 out of 5
Extension Builder in St James
Mani Buildworks Ltd is a trusted leader in the construction industry operating since 2015 offering high-quality services for residential, commercial, and industrial projects. With a commitment to excellence, safety, and sustainability, we provide tailored solutions that meet our clients’ unique needs. Our experienced team is dedicated to delivering projects on time and within budget, while maintaining the highest standards of craftsmanship and customer satisfaction. At Mani Buildworks Ltd , we build with integrity, innovation, and a focus on long-lasting results.
Get in touch
Latest review:
Plastering- 15 Oct 2018
Enrike plastered my mums hallway and gave her a good price for the work,was reliable and did a good job.
Rcm Buildrs
Rating: 5 out of 5
Extension Builder in St James
RCM Builders is an insured construction company which offers a multitude of services. Loft conversions, extensions, painting, plastering, fencing, building renovations, and bricklaying are a few specialities we covers. We have over 28 years worth of experience and are well versed in providing high quality work, great customer service, great costumer satisfaction and great communication.
Get in touch
Latest review:
Conversions - General- 7 Mar 2023
Have completed the job extremely well. Did a new door opening. Door fittings and plaster work . Very good finish. On time. Polite. Very pleased. Would hire again.
Cepele Construction
Rating: 5 out of 5
Extension Builder in St James
Introducing Cepele Construction Experience and Past Jobs: Cepele Construction has earned a reputation for exceeding expectations and delivering high-quality results. We have successfully completed numerous projects, such as the ones for James Smith and Teresa McTavish, ensuring that each client's unique vision is realized with excellence and professionalism. Where We Can Work: We operate primarily in London and the surrounding areas, offering our services to clients who need reliable and top-quality construction work. Special Skills: Our expertise includes loft conversions, customized construction solutions, and exceptional project management, ensuring every detail meets our high standards. Why Hire Us: At Cepele Construction, we are committed to providing top-quality services tailored to each client's needs. Our dedication to excellence and client satisfaction sets us apart as the best choice for your construction projects. For more information, visit our website at Cepele Construction
Get in touch
365 BUILDING LTD
Rating: 5 out of 5
Extension Builder in St James
At 365 Building, we focus on quality over quantity. With many years of experience across a wide range of construction and carpentry projects, we take pride in delivering work that is done to a high standard, completed on time, and kept clean and tidy throughout. What We Do We offer a full range of building services, including: • Carpentry & woodwork • Kitchens & renovations • Flooring & doors • Roofing • Extensions • General building and property improvements We approach every project with care, precision, and professionalism—whether it’s a small repair or a full home improvement. Why Customers Trust Us Our customers appreciate our attention to detail, respectful working style, and strong workmanship. We aim to make every client happy, and many of our projects come through recommendations from homeowners who value the quality of our work.
Get in touch
Latest review:
Hard Flooring- 23 Jan 2026
Great and honest work, very quick and flexible. Would 100% recomend
Vadym Kutsak
Rating: 3.7 out of 5
Extension Builder in St James
I have 7 years in basement, underpinning, extension. Was working at company "Hughes design&build" Have good knowledge in job
Get in touch
Latest review:
Groundwork & Foundations- 30 Mar 2026
Vadym did a very professional job. He is a good communitcator , and left the site clean and tidy.
Renovations.Tm
Rating: 5 out of 5
Extension Builder in St James
We are an experienced and reliable company specializing mainly in extensions, basements, conversions, skylights. We can carry out renovations or building works to your dream home. As we say, Well Done Is Better Than Well Said, come and check us out now !!!
Get in touch
Latest review:
Tomasz and team did various jobs for me (wooden floor, skirting boards, acoustic wall and floor insulation, plastering, painting, electric work etc). Top finish and workmanship, extremely professional and reliable, friendly, helpful, considerate, punctual, honest, tidy worker.

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.

Quality screening

Easily find verified local tradespeople. Just post your job to get quotes from tradespeople near you across the UK.

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.