Extension Builders in Welwyn Garden City

Name: Extension Builder
Brand: MyBuilder
SKU: extension-builder
Rating: 3.8 (14 reviews)

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Some of our top rated extension builders in Welwyn Garden City

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Aston Brickwork
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
My name is Sean Aston I have been a bricklayer for 6 years now. I have all kinds of experience, from working on a large construction site to smaller jobs such as extensions ,porch's and garden walls. Any and all tradesmen I use will be full qualified I also have all relevant insurance .
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Latest review:
Bricklaying- 30 May 2019
Sean was on time and very polite at all times. He completed the work very efficiently with no disruption whatsoever. He went out of his way to make sure the job was completed to our satisfaction. He cleared up afterwards and left the site very tidy. We would happily recommend Sean.
CNR Bricklaying & Building Services
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
CNR Bricklaying & Building Services. A friendly, family run brickwork business who speialise in all types of brickwork and restoration.
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Latest review:
Bricklaying- 19 Apr 2016
We have always found it a problem trying to match the correct tradesman to any work we have needed doing, so much so that many jobs have been left undone. You either end up with a personality clash, or just plain bad workmanship, well not this time. The entire process was a joy from start to finish, from the initial quoting process, to the completion and the standard of work was exemplary. Nothing seemed to be a problem for them and they were very pleasant to have around. We are busy drawing up a fresh list of jobs we need doing and would certainly thoroughly recommend them. If you have had any bad experiences in the past, give them a try, you will be very satisfied.
Bennett's restoration
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
We are a family run business with over 20years experience we pride ourselves on our work and have a passion for making our clients happy. we pride ourself on great service and offering a stress free project for our clients.
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Latest review:
We employed Bennetts Restoration after they came recommended from a friend, who couldn’t speak highly enough of their experience with them. They were really happy with their work and delighted with the results! We asked several builders to provide a quote for a major renovation and extension and James (the owner) came back promptly, with clear information and was friendly and transparent throughout this process (the same could not be said for other builders!) Throughout the job, James and his team were polite and respectful and kept our house as clean as tidy as possible, providing helpful advice and explanations along the way. The timescales were clearly communicated and any slight changes or issues addressed seamlessly. We were so impressed with Bennetts Restoration, that we have actually asked them to come back and do the work on our interior! Would 100% recommend – Builders of this calibre seem like a rarity these days!
Welwyn construction Ltd
No reviews yet
Extension Builder in Welwyn Garden City
Drawing on decades of experience within welwyn construction and partners, we can undertake Groundworks, Paving and Garden rooms along with General building requirements. Welwyn construction Ltd is a family run business, with a team of local trades. We aim to strive to deliver project quality at reasonable prices. Free Quotes always available. Trades we supply within the company: Structural Engineer and Designer Carpenters Groundwork and associated works. Gas Engineers Electrical works Paving and driveways Garden Rooms.
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Coste + Beno
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Coste + Beno is an experienced construction business with a strong residential background. We pride ourselves on balancing architectural ingenuity with fine craftsmanship, to offer specialist services to discerning clients in the premium residential sphere. Our bespoke approach has seen us creating bijoux bathrooms in Shoreditch to managing full-scale renovations on listed residences in Primrose Hill. We are looking forward working with you. Best, Coste + Beno
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Latest review:
Architecture- 27 Nov 2017
I contacted Marius because he had good reviews and wanted someone reliable and capable so design a single story extension with large external and internal bifold doors. I wasn’t disappointed - Marius has been excellent throughout the whole design process and produced drawings to a high standard which met our requirements. Marius was an excellent communicator and always available to give advice when required. Further more, he went out of his way to contact local authorities regarding any questions I had at no extra cost to clarify any uncertainties. I would highly recommend his architectural services - he was good value and very professional.
Lee Construction Builders LTD
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Lee Construction Builders LTD are your local Builders in Stevenage. We offer free quotations and can build your project for a fixed price. All our team are fully qualified and experienced tradesmen that have seen and dealt with every building challenge possible. We have a track record of happy satisfied customers as we provide a friendly, professional service, and are always respectful of our customers, understanding that our workplace is your home.
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Latest review:
Roofing (Pitched)- 17 Apr 2016
Fantastic job; quick reply; thorough professional job. Lee really likes doing the job right; certainly not a cowboy. He really took his time in assessing the problem. Very neat job from the inside and out. Highly recommended.
DRJ Homeimprovements
Rating: 4.9 out of 5
Extension Builder in Welwyn Garden City
DRJ Home Improvements Ltd provides reliable and trustworthy service completed to a high level of standards because I believe you don't need to move, Just improve. I have got 20 years experience in the building trade satisfying clients. We are a team that will get your job done from start to completion.
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Latest review:
Extensions- 17 Mar 2026
I would not use Dan again. Complete lack of expertise on certain aspects of this build resulting in a lot of stress for me. Failure to gain necessary permissions despite Dan's reassurances at the time. An error on Dan's part related in the entrance to my property having to become much smaller than I needed. Disappointed overall.
Feras
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
High quality
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Latest review:
Painting & Decorating- 25 Feb 2026
Good job, excellent painting and clean and tidy
PLG Works
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Property Care Specialists
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Latest review:
Carpentry- 21 Dec 2024
Great work from Paolo in upgrading my side alley gate which was not an easy task given its size. Paolo gave good advice thoughout and supplied quality materials at a fair price.
Craft Property Solutions Ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Craft Property Solutions is a leading property refurbishment and remodelling company that specialises in both the residential and commercial sectors. Our team of experts can carry out interior alterations, extensions, loft extensions, and office fit-outs. We also have a specialist tiling division that can handle all your tiling needs.
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Latest review:
Bathroom replacement. Team were very efficient and made additional effort to accommodate the tenants. Communication was great throughout.
Mng Roofing Ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Welcome to Mng Roofing Ltd – Your Local Roofing & Building Experts With over 20 years of experience, we’ve built a reputation across London and surrounding areas for reliable, high-quality construction and roofing services. Every job is handled by our trusted in-house professionals — we’re here to protect and enhance your home with care and precision. We specialise in: 👉 New Roof Installations – flat and pitched roofs in slate, tile, felt, bitumen, and modern PVC membranes. 👉 Roof Repairs & Maintenance – from small leaks to major refurbishments. 👉 Fascias, Soffits & Guttering – installation, replacement, and professional cleaning. 👉 Garage & Extension Roofs – tailored solutions for outbuildings and home extensions. 👉 Leadwork & General Roofing Services – high-quality lead flashing, detailing, and associated building work. 👉 Extensions – full design-and-build services to increase your living space and add value to your property. 👉 Loft Conversions – transforming unused lofts into bright, functional rooms while ensuring Building Regulations compliance. 👉 Outhouses – bespoke garden buildings designed and built to suit your needs, from offices to relaxation spaces. Whether you're dealing with a leak, planning a renovation, or considering a full extension or conversion, we tailor our work to suit your property and budget. We’re proud to offer honest advice, expert craftsmanship, and guaranteed results. When you choose us for your project, you’re not only getting skilled workmanship — you’re also fully protected by comprehensive insurance cover: ✅ Employers’ Liability (£10 million): Protects our team while they work on your property. If any of our staff are injured, you’re never at risk of being held responsible. ✅ Public Liability (£5 million): Covers accidental damage or injury to third parties. For example, if a falling tile damages a neighbour’s car, you’re completely protected. ✅ Products Liability (£5 million): Ensures you’re covered if any of the materials we supply and install turn out to be faulty or cause damage. In simple terms, our insurance gives you total peace of mind: whatever happens, you’re financially protected, and your property is in safe hands. 🤝 If you're looking for a builder and roofer who values safety, quality, and customer satisfaction—let’s talk. 📞 Feel free to message me now to arrange a free site visit and no-obligation quote.
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Latest review:
We recently had Mng Roofing Ltd carry out a new flat roof installation on our property, and we couldn't be happier with the results. From the first inspection to completion, the team were professional, reliable, and kept us updated throughout the process. The workmanship was excellent, and the site was left clean and tidy, and everything was completed on time. We now have peace of mind knowing our roof is watertight and backed by a guarantee. Highly recommend Mng Roofing Ltd to anyone needing quality roofing work done.
Arch Construction and Project Management Ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Arch Construction and Project Management Ltd is specialist of structural engineering, structural alterations,restoration, extensions, loft conversions and in middle&large sized projects on highest standard. We offer full building site and/or project management from concept to completion based on 22 years experience in construction industry with hassle and frustration free experience.
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Latest review:
Extensions- 12 Jan 2023
George and his team did an excellent job in building our extension and dealing patiently with our requests or changes. We had weekly face to face meetings with George and he would respond promptly to any issue. A very professional approach to the build project and an excellent result of build quality.
Design A View Limited
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
At Design A View we specialise in window and door installations, porch builds, conversions, structural alterations for new bifolds or sliders. We are Fensa and CPA registered offering insurance backed guarantee’s With 30 years experience in the industry we offer a wide range of quality products and a finish of work that sets us apart, creating new openings and improving existing. Products: We are proud to be an approved Origin supplier Also Cortizo Aluminium doors, sliding and bifold Standard U-Pvc, flush casement windows, vertical sliding windows and doors Wooden vertical sash, casements and doors We look forward to working with you
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Latest review:
Extensions- 21 Oct 2025
Quick, honest pricing and great advice to minimise the impact rather than trying to inflate it like other traders do. I would highly recommend Lee and his team.
1RightConstruct
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Extensions and Loft conversions , General building works, Kitchens and Bathrooms but can also carry out all Electrical jobs. We take great pride in our work and we enjoy to admire the transformation of projects from the beginning to end.
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Latest review:
Extensions- 28 Jul 2023
We recently had the pleasure of working with Marius, his skills and craftsmanship were truly outstanding! Throughout the construction process, his attention to detail was commendable. Every aspect of the project, no matter how small, was meticulously executed. Marius' expertise was evident in the precision of his work, and it was clear that he takes great pride in delivering the best possible results. Marius kept us informed at every stage, patiently explaining the progress and addressing any questions or concerns I had. This level of transparency and professionalism made the entire experience enjoyable and stress-free. Marius' dedication to quality was evident in the choice of materials he used, ensuring the durability and longevity of the finished product. He had an eye for aesthetics, ensuring that the final result not only met functional requirements but also looked stunning. Not only was Marius skilled and reliable, but he also completed the project within the agreed timeframe and budget. His efficiency and commitment to deadlines were highly commendable. In summary, I can confidently say that Marius' work is truly great. His exceptional skills, attention to detail, clear communication, and commitment to excellence made the entire construction process a delightful experience. I highly recommend Marius to anyone in need of a reliable and talented builder.
J.c.s.builders and gardening services
No reviews yet
Extension Builder in Welwyn Garden City
J.c.s.builders and gardening services. General building work undertaken. From roofing repairs to full roof installations guttering facia and sofic install. Garage conversions. Bathrooms kitchens gardening all aspects of work undertaken. I've got over 25 years experience in the building trade. I take pride in my work. I've got liability insurance. I treat my customers with respect and care and give the best price. O.a.ps get a discount as I like to look out for there wellbeing. J.c.s.builders and gardening services the name you can trust
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Newell groundworks ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
A small family run business with over 20 years experience.
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Latest review:
Groundwork & Foundations- 15 Oct 2025
Stuart was great to work with. Knowledgeable, hardworking and committed to doing a great job. We will be using his services again in the future.

3.8

Top rated Extension Builders

Our Extension Builders in Welwyn Garden City, are rated 3.8 out of 5 based on 14 reviews from customers like you.

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What types of services are offered by local extension builders in Welwyn Garden City?

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 Welwyn Garden City 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 Welwyn Garden City who are available and interested can respond to your post.

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

What are the hourly rates of extension builders in Welwyn Garden City?

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

Find extension builders in Welwyn Garden City with MyBuilder

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

Step 2: Compare different extension builders in Welwyn Garden City

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

Step 3: Hire Welwyn Garden City extension builders with confidence

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

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

What to ask a Welwyn Garden City extension builder before hiring?

Before hiring an extension builder in Welwyn Garden City or extension building company in Welwyn Garden City, 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 Welwyn Garden City?

An extension builder in Welwyn Garden City 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 Welwyn Garden City 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 Welwyn Garden City?

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 Welwyn Garden City 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 Welwyn Garden City 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 Welwyn Garden City

Can an extension builder in Welwyn Garden City help with planning permission?

Yes, many extension builders in Welwyn Garden City 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 Welwyn Garden City handle everything from design to construction?

Many Welwyn Garden City 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 Welwyn Garden City help with materials and finishes?

Yes, most extension builders in Welwyn Garden City 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.