Extension Builders in Westminster

Name: Extension Builder
Brand: MyBuilder
SKU: extension-builder
Rating: 4.1 (17 reviews)

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Some of our top rated extension builders in Westminster

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StructurAll Ltd
No reviews yet
Extension Builder in Westminster
We started our company as an engineering consultancy. We developed over the years to provide in-house architectural services, interior design, structural design, project management and asset management capabilities. We believe in client service and support throughout the life of a project, rather than just providing a design solution. So we have gained a reputation of being a one-stop-shop amongst our clients; who include private individuals, contractors, and local authorities.
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Jm building & restoration
Rating: 5 out of 5
Extension Builder in Westminster
I'm Joe I've been doing re-pointing, restoration and general building works for over 10 years now. I've always worked within the construction industry but in recent years I've mainly been based within house building and extensions starting from groundworks to roofing.
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Latest review:
Bricklaying- 31 May 2020
Highly recommend. Very pleased with his workmanship. Neat, to time and professional.
hrs build ltd
No reviews yet
Extension Builder in Westminster
We are specialize company for interior and exterior ,extension refurbish painting and decoration chimney removal roof construction loft conversions .
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ALFAC LTD
No reviews yet
Extension Builder in Westminster
About Us: Welcome to Alfac Ltd, where craftsmanship meets excellence! With a passion for building dreams and transforming spaces, Alfac Ltd stands as a trusted name in the construction industry. Established with a commitment to quality, innovation, and customer satisfaction, we bring your visions to life, one brick at a time. Services We Offer: Home Renovations House Extensions Loft Conversions Kitchen and Bathroom Remodeling New Builds Structural Repairs and more...
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FDT Construction Services Limited
No reviews yet
Extension Builder in Westminster
Construction company specialising in home extensions, loft conversions, patios, driveways and other construction services. You name it, we are here to help!
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Serg Build
Rating: 4.7 out of 5
Extension Builder in Westminster
Customer friendly, professional building service. Works covering:extensions, loft conversion, complete house renovation, kitchen and bathroom fitting, flooring. Great attention to detail to building process as well as design and planning. Don't hesitate to contact for a free quotation.
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Latest review:
Kitchen Fitting- 23 Aug 2021
Great service, went above and beyond to help us finish the job.
Km Building Specialists Ltd
Rating: 3 out of 5
Extension Builder in Westminster
KM Building Specialists is dynamically developing company created by people with passion. Our mission is professional advice, meeting expectations and, as a result, obtaining satisfaction of all our clients. We work closely with various construction specialists (electricians, gas-safety experts, architects, garden designers) to enable us to deliver the top class service and to ensure that the safety building regulations and codes of practice are followed.
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Latest review:
A single storey extension. Bedroom chimney place knocked down. Patio to the rear. Marek was very hardworking, professional and tidy. He was at my home every day and alway very early and always worked until late to get the job done
Kasa
Rating: 5 out of 5
Extension Builder in Westminster
Kasa Building services , it’s proud to offer a wide range of services from new build to loft&extensions , refurbishments , plumbing and electric,carpentry and loads more … With as quality matters
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Latest review:
Plumbing- 3 Apr 2023
Kasa was absolutely fantastic, nothing was too much hassle as we had to make changes during the job. We have now found a plumber, we can use on all future projects. Big thank you Kasa from myself and Aiste.
builder
No reviews yet
Extension Builder in Westminster
14 years of experience in plastering, tiling, bathroom and kitchen fitting. I have my own team of skilled builders
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B&D Construction London Ltd
Rating: 5 out of 5
Extension Builder in Westminster
Hi Our company undertake jobs ,Loft Conversion, Extensions, Carpentry, Gardens, Plumbing/Electrical , Plastering and Decorating,
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Latest review:
We’ve had multiple jobs done by Silviya. The first was a small extension and downstairs and partial upstairs refurbishment with new kitchen and 2 bathrooms fitted. This large job was completed within 16 weeks and looks exactly as we hoped. Given the extent of works we moved out for the build. The second was the construction of an outbuilding and garden redesign (patio and astro fitted). Again the results are great. We lived in during this project and I worked from home without disturbance. The latest has been the re-fit of new windows, front door and fixing the front render. Again, the results are very professional and minimal disturbance while the work took place. Will definitely use him and his team again, should we need any more building work and recommend them to others
Duo Builders Ltd
Rating: 5 out of 5
Extension Builder in Westminster
Duo Builders offers customers a high end service for all domestic building works. Our highly qualified team undertake Design, Build and Maintenance works on residential property in London and the surrounding area. Our wide range of services allows our clients access to an efficient quality service.
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Latest review:
Conversions - General- 26 Dec 2021
Overall, Duo Builders is good and I would recommend for any build work. Pros: 1. Committed to work and informed when not coming on any particular day 2. Had manpower allowing to add more hands if needed 3. Reliable people and nice staff / Team of young members 4. Does and completes work that was planned and agreed Cons: 1. Job took a lot of time than estimated as it was not thoroughly thought how the earth would be moved 2. Very hard to hold off the owner, its important for the client to be stay connected and informed. 3. Bit messy and site gets put of shape than original
NORTH STAR BUILDING SOLUTIONS LIMITED
Rating: 5 out of 5
Extension Builder in Westminster
Established in 2010 Northstar Building Solutions are a highly successful building company specializing in exceptional residential projects. As well as covering all aspects of new build and can deliver technical expertise to the latest building designs. We pride ourselves in completing a variety of projects including affordable and high specification housing, energy centres, hotels, restaurants, community centres and a church; we are experts at Extensions, Conversions.
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Latest review:
Extensions- 2 Jan 2023
Excellent work overall. Builders were very professional, hardworking and friendly. Work was completed to a high standard and we were given updates throughout the entire process. Leo and his team were very responsive and resolved issues very quickly. Will 100% use North Star again for future work.
AVisha Builders
Rating: 5 out of 5
Extension Builder in Westminster
Hi, I’ve been a builder for over 25 years now, working on mainly domestic houses I specialise in plastering and tilting. I have also completed extensions and loft conversations from start to finish. Happy to have a chat about your needs!
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Latest review:
Plastering- 26 Mar 2025
I am really impressed about Avisha's job... quick response , great service with very reasonable price.... Will absolutely recommend...
Onyx Interiors London Ltd
No reviews yet
Extension Builder in Westminster
Onyx Interiors London (OIL), is an all-inclusive creative platform dedicated to private clients, property investors and developers, who require a specialized or ongoing service designed to their specific needs.
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Ava Constructions & Decors
Rating: 4.9 out of 5
Extension Builder in Westminster
Ava Constructions & Decors Ltd is a UK-based construction and renovation company committed to delivering top-quality craftsmanship and reliable project management. We specialise in full refurbishments, extensions, bathroom and kitchen installations, and commercial fit-outs — always tailored to the client’s vision and delivered to the highest UK building standards. With a keen focus on transparency, timelines, and customer satisfaction, Ava Constructions has earned the trust of homeowners, investors, and developers alike. Punctuality and completion of work on time are a priority .Our team always respect the client wishes and work with them to achieve the best possible results to their satisfaction. Thank you in advance
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Latest review:
Extensions- 16 Apr 2026
I would not recommend this builder based on my experience. Instead of using crushed concrete they used soil to fill the house flooring for underfloor heating. 1 The project suffered from poor communication, repeated delays, and a lack of clarity around responsibilities. There were serious issues with the foundation works, which failed Building Control inspection and now require remedial engineering input before works can proceed. The site was also left incomplete and not in an acceptable condition. Despite substantial payments being made, key documentation, technical responses, and follow-through were lacking, leaving me to resolve major compliance and structural issues independently. My experience has resulted in delay, additional cost, and considerable stress. I would strongly advise others to ensure there is a detailed written contract, clear scope of works, and defined accountability
HEXAFORM CONSTRUCTION LIMITED
Rating: 5 out of 5
Extension Builder in Westminster
HEXAFORM is a London based multi-disciplinary design and build company that has the experience, work ethic, communication tools, and systems in place needed to bring any scale project from a virtual blueprint to reality. Historically the architect-contractor relationship has been one of an ‘us versus them’ mentality. But we’re 'both'. Having a design team under the same roof as a construction company means that the eccentricities of each project are rendered opportunities, rather than obstacles.
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Latest review:
Architecture- 12 Jun 2023
Lots of ideas, step by step explained. Easy to work with. Highly recommend

4.1

Top rated Extension Builders

Our Extension Builders in Westminster, are rated 4.1 out of 5 based on 17 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 Westminster?

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 Westminster 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 Westminster who are available and interested can respond to your post.

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

What are the hourly rates of extension builders in Westminster?

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

Find extension builders in Westminster with MyBuilder

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

Step 2: Compare different extension builders in Westminster

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

Step 3: Hire Westminster extension builders with confidence

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

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

What to ask a Westminster extension builder before hiring?

Before hiring an extension builder in Westminster or extension building company in Westminster, 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 Westminster?

An extension builder in Westminster 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 Westminster 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 Westminster?

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 Westminster 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 Westminster 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 Westminster

Can an extension builder in Westminster help with planning permission?

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

Many Westminster 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 Westminster help with materials and finishes?

Yes, most extension builders in Westminster 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.