Extension Builders in Welwyn Garden City

Name: Extension Builder
Brand: MyBuilder
SKU: extension-builder
Rating: 3.9 (16 reviews)

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Some of our top rated extension builders in Welwyn Garden City

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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.
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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D & C Kitchen Installations Limited
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
We undertake full or part refurbishment or existing and new build works. We specialise in kitchen installations and building alterations. We can provide a full team of specialist to complete all building works from design to completion. We are a registered Ltd company, fully insured and members of BiKBBi and only use registered contractors.
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Latest review:
Ciaran ripped out my old kitchen and installed a new one and at the same time adding a door to the garage. Ciaran’s workmanship is second to none, his eye for detail and knowledge is awesome. Ciaran is a true very polite and all together a sound tradesmen. Always here early and put in the hours. I would absolutely recommend Ciaran and his work it was well worth the wait. Thank you.
RV DEVELOPMENTS
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
An established and proven family business who have recently partnered with Tf builders to become Thomas Richards. Still working to the highest standards. Specialising in new build developments Extensions and conversions
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Latest review:
Extensions- 1 Jun 2012
Great job. Reliable and high quality work.
Gary prime
Rating: 4.5 out of 5
Extension Builder in Welwyn Garden City
I have been actively involved in the construction industry for the past seven years, during this time I have gained experience in ground works, bricklaying and a variety of other trades and in the last two years I have been working in a supervisory role. I have worked on large construction sites as well as carrying out works on property refurbishments.
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Latest review:
Groundwork & Foundations- 14 Aug 2019
Gary did an excellent job on the drainage, everything I asked of him. He was punctual and polite, wouldn't hesitate to hire him again.
B H Construction
No reviews yet
Extension Builder in Welwyn Garden City
B H Construction can assist you with all aspects of the building trade including extensions, refurbishments, structural alterations and all other trades. We pride ourselves on our high standards of work and have many years experience in the trade. We work closely with a kitchen company if you require a kitchen refurbishment and we also fit bathrooms from fairly basic installations, to very high spec. Fully insured
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D Bird carpentry and building LTD
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Hi were Dbird Carpentry & Building we are a family run company by myself Daniel and my brother Ellis. We take pride and love what we do! We will help you every step of the way through your project no matter the size.
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Latest review:
Conversions - General- 21 Jun 2022
D Bird Carpentry completed the works on time and to a high standard. Dan and his team were a pleasure to work with and I would be happy to work with them again.
B D construction
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Have been a builder for forty years family run business with my son’s working with me.
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Latest review:
Brad and his company have done various jobs in my house including painting and decorating - refurbing my bathroom (which is amazing) and putting a new roof on my shed. He also does a lot of conversion and refurbing work for the Property Investment company that I work for and all to a very high standard. He is professional and hardworking and wouldnt hesitate to use his company for future work as well
Nick's Authentic Carpentry and Building
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
We're a new company but have the experience and knowledge of any other company.We're professional, organised, and give our customers what they expect and deserve. Being proud workers and undertaking everything thats thrown at us, Our focus is the job we're on!
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Latest review:
Carpentry- 31 Aug 2011
Highly recommended and friendly carpenter. The job was done within 24 hours of posting. He gave me a time and even called to say he was on his way. Price was very reasonable indeed. Job was done to my total satisfaction with 100% professionalism. I am certainly going to have Nick do any other jobs that arise. He clearly has a vast knowledge of a whole range of trades and skills apart from carpentry. It is so nice to have found such an able tradesman who can be trusted to do a great job.
PWD CONSTRUCTION LTD
Rating: 4.9 out of 5
Extension Builder in Welwyn Garden City
I established my business to meet the needs of homeowners looking for skilled and qualified tradesmen that put trust at the top of their requirements. From small jobs to large extensions and landscaping we can help to make your property dreams come true. Money back guarantees offered.
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Latest review:
Extensions- 7 Sep 2026
Paul did an absolutely amazing job building a new porch for us! Nothing was too much trouble, he dealt with all issues and kept us informed along the way- the end result is exactly what we wanted. He’s a really lovely guy too, have already asked him for a quote for the next job! Thanks Paul :)
LandMarx Ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Small friendly family run business with over 30 years construction and refurbishment experience. We offer all types of building services wether it is a small maintenance job to a new build . We work on commercial and residential buildings. We also provide project management for self-builders who want to keep to a budget and have someone with the expertise to guide them through the building process from conception to finish. We are CHAS accredited and DBS checked.
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Latest review:
Keith has helped design and fit our kitchen/utility room. Has re felted the flat roof on my garage and extension. He is currently fitting all my doors, skirtings and door linings. He boarded up and plastered doors where we have removed cupboards and larders. Great job, very reliable and multi trade so i would highly recommend him. I'm an electrician so work with a lot of builders so i can recognise a good workman.
DJ Cox Building Services Ltd
No reviews yet
Extension Builder in Welwyn Garden City
All building work, extensions, loft conversions, electrics, plumbing, plastering, bricklaying, patios, drives, bathroom & kitchen fitting, fencing.
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schertel build Ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
we will always ensure quality service and respect to your property at the best available price. 7 years experience in brickwork, specializing mostly in garden walls
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Latest review:
Connor re-pointed my patio and I’m really pleased with the results. The finish looks fantastic and has made a big difference overall. He worked efficiently, kept everything clean and tidy, and was great to deal with from start to finish. Very reasonably priced too. I wouldn’t hesitate to recommend him. I will definitely be calling him back when I need other work.
AJK Building
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
AJK BUILDING is a trusted name in the construction industry, delivering high-quality building solutions with a commitment to excellence, integrity, and innovation. With over 16 years of experience, we specialize in providing comprehensive construction services that include residential, commercial, and industrial projects. Our team consists of highly skilled professionals who work collaboratively to bring each project to life with precision and care. From initial planning and design to final execution, we ensure every phase is handled with professionalism, transparency, and strict adherence to timelines and budgets. At AJK BUILDING, safety, sustainability, and client satisfaction are at the core of everything we do. Whether it’s a small renovation or a large-scale development, we are dedicated to building spaces that last and relationships that grow.
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Latest review:
Decking- 3 Jun 2026
Anthony did a great job from start to finish. Having had a few quotes, some cheaper, I decided to hire Anthony for the job as his quote was fair, thorough and clear about the process, materials, time needed, I did not get this assurance from some of the cheaper quotes. He listened carefully to what I was looking to do and make some good suggestions to help achieve the look I wanted for my decking. Communication was clear at all times during the job. Once the job started, Anthony was punctual each day, organised and ensured the site was kept clean at all times. I am very happy with the decking and standard of work achieved. I would highly recommend Anthony and AJK Building and would definitely hire him again for any future jobs.

3.9

Top rated Extension Builders

Our Extension Builders in Welwyn Garden City, are rated 3.9 out of 5 based on 16 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.