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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Jgs carpentry
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Jgs carpentry & building services. We are hardworking, trustworthy carpentry and building company based in Hoddesdon. With 20 years experience in the building trade doing anything from hanging a few doors to loft conversions and extensions
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Latest review:
Carpentry- 23 Nov 2019
We had 7 new internal doors fitted. Really great job, very pleased. Would highly recommend.
Philip J Pulzer
Rating: 4.7 out of 5
Extension Builder in Welwyn Garden City
As a design and build contractor, we will produce drawing for both planning approval and building regulation. We will then provide a detailed estimate of building costs. If we do win the building co tract then all architectural design cost will be free of charge.
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Latest review:
Extensions- 11 Feb 2019
Completed job on expected timeline and assisted when challenges came up
Oliver Building Services Limited
Rating: 4.8 out of 5
Extension Builder in Welwyn Garden City
About Oliver Building Services Ltd, have been fitting kitchen and bathrooms for many years. We pride ourselves on being the go-to bathroom fitters for discerning . We specialise in all bathroom fitting and design services including: Please feel free to get in contact and we will be more than happy to come round to quote •Extension •Kitchen •Bathroom •Installation •Showers •Plumbing •Tiling •Plastering •Electrical •Painting & Decorating • Loft conversion •Roofing
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Latest review:
Kitchen Fitting- 27 Nov 2024
We decided to fit a new kitchen in our tenanted house all done remotely via Australia. We are very pleased with the final kitchen and credit to Oliver for staying committed to the job. He communicated well throughout the process and as a result there were no surprises. This was not an easy process as we were dealing with a difficult tenant that we were trying to remove at the time. As a result the new kitchen was fitted but Oliver had to come back months later to finish the job. I know this was frustrating for him but with mutual respect and trust we got the job finished and I thank him for his patience and honesty. Would recommend his services.
B & M Home Improvement
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
We are a local and reliable Plumbing, gas safe and Home Improvement Company in London and surrounding areas.I gained my experience working in the Plumbing and gas department. No matter whether you require help with plumbing, power flushing, boiler installation, bathroom, kitchen, extention, flooring we take on all building work. We provide a full interior decorating service for domestic and commercial.
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Latest review:
Extensions- 10 Apr 2014
Max and Bob completed the extension on time and within budget. There were no hidden extras and despite Bob being on holiday for two weeks, Max worked hard and lon. The extension is 6m x 5m. There were issues with Building Control which Max sorted out and did everything to meet their requirements. The extension is built to a high standard, kitchen cabinets fitted well, tiling very good and we are pleased with the quality of their work. We are using B&M again as we are confident that although they are not tghe cheapest, the quality of their work is of a high standard. Besides, it is always a pleasure to deal with Max who is a gentleman, patient and listens to what is required.
PS Brick Block &Home Improvement LTD
Rating: 4.7 out of 5
Extension Builder in Welwyn Garden City
All type of building works to high standards. - extensions - lofts - plumbing - electric - decorating - new build - patios - driveways
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Latest review:
Extensions- 4 Nov 2023
Overall me and my husband are very satisfied with the workmanship and with the final result of our my fake cladded garage door with the new aluminium framed window. The original garage was converted into a habitable room 7 years ago with only a rooflight to bring light into the room, which is now my husband's office and this new window will make a lot of difference therefore we are very happy with the finished work. The work was done very quickly, the builders turned up on time and they were very efficient and helpful, they took particular care when installing the composite slatted panels to the marine plywood. The main contractor Pawel Speiwak also came on site to inspect the works during construction. The quote was also very competetive, a good value for money. I would definetely use them again for any future work in my house and recommend them to other people.
RDP Construction
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Small building company covering all aspects of building specialising in bathroom & kitchen installations , experienced tradesman with a huge knowledge of the building trade with polite free advice given & free quotations. If you require more pictures of my works then drop me an email and I can send them . Regards Mr R D Pulfer
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Latest review:
Bathroom Fitting- 24 Feb 2020
Russell finished our bathroom in high standard. We are so happy that we found him. I trust his work and I would recommend him over and over. Thank you Russell!
Painting & Decorating
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Probably the most important characteristic that define our team is that we like what we are doing and we take pride in any single job.We do our work in detail and make sure every step on prep work is done properly as well as the materials we using are a good quality and long lasting.We are doing high quality jobs,at resonable prices,both residential and commercial.If you are looking for painters you can trust and have your painting job done properly&clean then we are the ones you're after
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Latest review:
Handyman- 8 Jun 2026
Absolutely fantastic job. Julian was really friendly, arrived on time, did an amazing job fitting the wall panels and cleaned up afterwards. I cannot recommend him highly enough, and will certainly be using his services again
Hatch Building & Construction LTD
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Hatch Building & Construction are a local family run business who take pride in their reputation, delivering a high standard of work and completion on all projects. We offer a full design service for all our projects incorporating architects, structural engineers and designers, this means we can offer a full in house service from conception through planning, building control and conservation. We are a member of the FMB where you can find testimonials from previous customers.
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Latest review:
Extensions- 10 Jul 2019
The initial reason we chose Hatch Construction to start is down to Lee.......... Text missing Cleanliness – Not only I have commented, but each of my neighbours who are all elderly were very complimentary about how the team worked and how clean the site was. I was very happy that my patio and garden were all left intact. Staff – A great team, knowledgeable, friendly and flipping hard workers. Nothing was ever a chore for them and they were happy to share their knowledge and experience. An overall lovely group of blokes. Quality of Work – The workmanship was spot on, even with a knowledgeable family member at hand to oversee some of the build, he was more than happy with the workmanship demonstrated by the guys. Been in the house a month or so now and all appears to be as it should be. Knowledge of Suppliers – The Company has links to many reputable companies in the area to put you in contact with, we used all that were recommended to us and we couldn’t better the price and service anywhere else without dipping on quality. Flexibility – A very flexible team, whether time constraints or having to work around certain events, Lee will aim to make it as plain sailing as possible, given that having building work is such an upheaval. Overall I would recommend Hatch Construction to anyone, they are an honest firm and will do their best on the job in order to meet your expectations. I am more than happy with my new house and love what they have done to transform it
R Rexha Builders
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Extensions - Porches - Garages - Lofts conversion - Kitchen fitting - Bathrooms - Carpentry - Repointing - Painting -Decorating (interior / exterior)
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Latest review:
Extensions- 21 Sep 2019
Ray has done an outstanding job with the new extension. He has shown great attention to detail and accommodated every request. The result is one that we are extremely happy with. He installed a new bathroom downstairs complete with all necessary pipework and a new utility closet with exits for the washing and dryer. Clearly Ray has a very broad set of skills, from electricity to building to carpentry, plumbing and roofing. He really was the one stop shop to make this extension a reality and has a network of people he can call onto if required. He is certainly someone that takes pride in his work and wants a job well done as evidenced by his work. I recommend Ray without a doubt and I'm sure our paths will cross again. Thank you Ray!
Arlo
No reviews yet
Extension Builder in Welwyn Garden City
Our company offer these services: Landscaping Services •Paving •Driveway •Fencing •Grass •Cleaning •Drainage •Garden Repair •Concrete Base •Wooden Pergola
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Urwin services
No reviews yet
Extension Builder in Welwyn Garden City
We are a driveway clearance and demolition specialist, all aspects of clearance and demolition undertaken, competitive rates clean and efficient working in home counties and north London
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P Jordan and Sons Ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Jordan & Sons are a family run business with over 30 years experience specialising in extensions, new builds, all types of groundwork, drainage, brickwork, driveways, patios, resin bound & block paving. The work we carry out is second to none, finished to a high standard while providing an excellent service. We own our own plant with relevant tickets, & we take on all commercial and domestic projects.
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Latest review:
Extensions- 10 Mar 2025
Hired paul to carry out works to open up my rear wall and install a new RSJ steel beam for a bifold door. From day one paul helped me out with some issues i was having with my structural engineer design, priced up the works which was very competitive with other builders and While having a visit before works started, i asked paul if he could do some extra works (installation of plasterboard walls and plastering) which he was happy to do. Todd then started works within a few days. Now all the works are finished and im very happy with the finished product. Paul and Todd were brilliant and would happily recommend them to people if they need any works done. I will be using them again in the future.
Ferrity Construction & Home Improvements
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Ferrity Construction is a Hertfordshire-based construction company delivering high-quality workmanship across a wide range of projects. We pride ourselves on a professional approach, attention to detail, and completing every project to the highest standards. Our areas of expertise include: - Insulation and thermal efficiency works - Retrofit solutions - Full home refurbishments - External Wall Insulation (EWI) - Roofing - Rendering - General building services - Patios - Electrics - Plumbing - Maintenance and repairs
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Latest review:
Restoration & Refurbishment- 27 Mar 2026
Excellent job to board out garage and lay flooring. Very professional, good value, highly recommended.
KBS Construction Services
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
In our offer we have a wide range of construction services such as: • Extensions • Conversions • Renovations • Kitchens • Bathrooms-Washrooms • Property Maintenance • Handyman Service • Refurbishment • Brick work etc • Specialist Stone, tiling etc. • Painting & Decorating • Window fitting • Architecture Steel Fixing • Under floor Heating and many more
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Latest review:
Restoration & Refurbishment- 8 Jun 2020
Kamil and his tiler have been excellent. He was able to do the work at short notice, he always turned up on time and stuck to his quote. The quality of the work is excellent with special mention of the tiling which would probably win a competition! Kamil remedied minor problems that occurred as the work was in progress ensuring that the completed work was first rate. I will certainly use Kamil again and have no hesitation in recommending him to others.
OFIX Ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
With over 34 years experience I offer a complete design and build package as well as providing specific services for smaller contracts. I have been vetted by the Federation of Master Builders and strive to provide excellence. I am an extremely competent multi trader with a good eye for detail. With a team of experienced subcontractors I will deliver incredible quality installations on time within budget.
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Latest review:
Carpentry- 8 Mar 2025
Absolutely over the moon with Mike, he did a fabulous job. Would definitely recommend him!
D&N construction
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
D&N CONSTRUCTION ARE A POTTERS BAR BASED BUILDING AND HOME IMPROVEMENT COMPANY WITH MANY YEARS OF PROFESSIONAL EXPERIENCE. Whether it’s improving your outdoor space, or extending your home, D&N Construction is here to help you every step of the way. We have many years of experience in renovations and all building work At D&N Construction , we’ve built our livelihoods on building peoples’ dreams across Hertfordshire. we’ve experienced it all we can help you . No job is too small or too big!
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Latest review:
Carpentry- 8 Oct 2025
Nick fitted a single pine internal door for me in the Letchworth area. He was very easy to work with, communicated promptly and clearly throughout, and was neat and tidy during the installation. I’d happily recommend his services.

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.