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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PrimeUKContractorsLtd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Prime UK Contractors is a London-based construction company providing high quality work for a reasonable price. Our projects are always finished on time. Our priority is the satisfaction of our clients. Our team consists of skilled, experienced builders who will help you execute your dream project.
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Latest review:
I recently used PrimeUK Contractors Limited for conversion works at our studios in Camden, and I couldn’t be happier with the results. The project timeline was set at six weeks, and the team delivered right on schedule. Pavlo and his team had a clear understanding of the scope and what needed to be achieved, going above and beyond to make the project a success. The quality and attention to detail in their work were outstanding, and my entire team was thrilled with the final result. Their pricing was competitive and fair, which was another bonus. When we have more work in the pipeline, Pavlo and PrimeUK will definitely be my first call. Highly recommend!
Darkwall Ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
We specialise in interior, exterior painting and offer a friendly and professional service with a guaranteed competitive prices. All work is done to a highest standard.
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Latest review:
Painting & Decorating- 1 Oct 2022
I have been looking for a great painter for quite a few time before finding Silviu. I can only say that I am very pleased by his work and the professionalism he demonstrated throughout the job! He even gave me a few ideas for the overall decoration of the room once the paint is done. I definitely recommend him, and I look forward to work with him again for any future projects!
Dino design Ltd
Rating: 4.8 out of 5
Extension Builder in Welwyn Garden City
We founded DINO DESIGN out of a pure passion for building. We are two brothers who work together in sync and is a collaboration we're proud off, we construct roofs extensions and loft conversions to an amazing standard which can be seen in the work we do. We like to push boundaries in our field making a project built by DINO DESIGN stand out from the rest. DINO DESIGN is a name you can count on and trust to deliver your project from the paper its drawn on to the material its built from. Explore the rest of our site to learn more about what we offer, and get in touch with any questions. We specialise in: • Single & double-storey extensions • Loft conversions & dormers • Full property refurbishments • Kitchen transformations • Open-plan structural alterations • Landscaping and outdoor works
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Latest review:
Conversions - General- 22 Apr 2026
Had a fantastic experience with Dino Design for an en suite removal. They understood exactly what I wanted and were very responsive throughout, giving me daily updates about how the work was going. So happy with the result- would 100% recommend :)
Felton Home Renovations
No reviews yet
Extension Builder in Welwyn Garden City
Hi my Names Brad We are a New and fast growing company based in Harpenden taking on a variety of work from small carpentry jobs to major Refurbishments/Extensions we only use fully qualified trades and lead by example in the building industry.
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North Builders LTD
Rating: 4.8 out of 5
Extension Builder in Welwyn Garden City
North Builders LTD have a team of specialists which gives you quality and high standard work on Loft conversions, Extensions, Roofing, Renovation, Refurbishment. We based in London and we cover all M25. With the best quality work and proffesional prices on the market we managed to make happy a lot of costumers around London and not only. Our priority is the costumer to be satisfied, the project to finish in timeline and on budget. Contact us for free quotes.
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Latest review:
Loft Conversion- 2 Nov 2025
Full loft conversion with dorma. Blerim always asked the right questions and made really good suggestions. Very helpful and great quality. Would happily recommend him and his team.
Slateriver Group Limited
No reviews yet
Extension Builder in Welwyn Garden City
Our highly-experienced team cover everything from light to heavy refurbishments, as well as new builds. We’re experts at transforming spaces, with minimal disruption. So, whether you need a brand new development or alterations to an existing space, we can navigate all the complexities on your behalf so that you can enjoy watching your vision emerge.
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Redriver loft converters ltd
No reviews yet
Extension Builder in Welwyn Garden City
Welcome to Red River Loft Convertors Limited At Red River Loft Convertors Limited, we specialise in transforming homes with high-quality loft conversions, house renovations, extensions, bespoke kitchens, and luxury bathrooms. From initial design through to final installation, we provide a complete, end-to-end service tailored to your needs. Working closely with experienced architects and structural engineers, we can guide you through every stage of your project. Whether you're looking to create additional living space, modernise your home, or undertake a full renovation, our knowledgeable team is here to offer expert advice and professional support from the very beginning through to successful completion. With a commitment to quality craftsmanship, attention to detail, and excellent customer service, we take pride in delivering beautiful, functional spaces that enhance both your home and your lifestyle.
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ALTD_carpentry
Rating: 4.8 out of 5
Extension Builder in Welwyn Garden City
Altd Carpenry specializes in transforming homes through expert loft conversions, extensions, and comprehensive house renovations. With a commitment to enhancing living spaces and adding value to properties, we offer innovative solutions that blend functionality with aesthetic appeal. Maximizing your home's potential by converting unused attic spaces into stylish and functional living areas, such as extra bedrooms, offices, or lounges. We handle all aspects, including design, structural work, and finishing touches. Revitalizing your property through comprehensive renovations. From modernizing interiors and updating kitchens and bathrooms to complete overhauls, we ensure your home reflects your vision and enhances its functionality. Our team collaborates closely with clients to create bespoke designs that align with their needs and preferences, ensuring every project is tailored to individual requirements At Altd Carpentry , we are dedicated to transforming your home into a more comfortable, stylish, and functional space. Whether you're looking to create additional living areas, expand your home's footprint, or undertake a complete renovation, we have the expertise and dedication to turn your vision into reality.
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Latest review:
Restoration & Refurbishment- 8 Jan 2026
I’m extremely happy with the work carried out by Arindo @ Altd Carpentry. From start to finish, the refurbishment was handled in a very professional and organised manner. The work was completed on time, exactly as agreed, and the quality of workmanship throughout the house is excellent. Everything from the kitchen installation, flooring, tiling, carpentry, electrics and painting was done to a high standard, with great attention to detail. Communication was clear throughout the project, and any questions or small changes were dealt with promptly and without fuss. The site was kept tidy, Arindo was respectful, and it’s clear he and the team take real pride in their work. I wouldn’t hesitate to recommend Altd Carpentry to anyone looking for reliable, skilled, and trustworthy builders. I would happily use them again for future projects.
Urban Modern Homes
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
We are a team of highly skilled individuals, with a great sense of professionalism and integrity. Our purpose is to deliver the transition from our customer's vision to reality and strive to bring satisfaction and joy with the results of our work. We aim to offer the best possible service while building trust with our clients. Having over a decade experience in the building industry, gives us the possibility to be quick, flexible and efficient.
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Latest review:
Carpentry- 11 Jan 2023
This was a great experience with a builder who arrived when he said he would and did what he said he would do! Identified the problem we had and got to work repairing it! Super efficient and nice to deal with! Thumbes up!
Grand Improvements Ltd
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
My business partner Jake and I have been in the building trade for over 15 years. We undertake projects of all sizes, giving professional advice to meet your renovation needs. Our customers are aways highly satisfied, which intern leads to repeat business. The Grand Improvements team are polite, tidy, efficient, and take pride in completing every job to a high standard.
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Latest review:
Plastering- 24 Aug 2020
Byron replied to a job quickly, quote was what we have expected and he accomodated specific date we needed this done by. Communication from the beginning until the end was great, he explained everything clearly, advised day before what time will they be arriving and arrived in time. Did a fantastic job plastering living room ceiling and cleaned up the floor afterwards as well. Very pleased and will definitelly be employing again for any future jobs. Thank you!
crimson kite construction
No reviews yet
Extension Builder in Welwyn Garden City
Fully experienced, impeccable attention to detail. Able provide a design service or complete a project to architect specifications.
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ERIC GROUP LTD
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Eric Group Ltd has been trading for over 10 years and has completed numerous refurbishment and fit-out projects. We offer free survey and estimates and free specialist advice. If you want a new kitchen, a new bathroom, a house extension or a full house refurb, get in touch for a chat.
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Latest review:
The Job was to extend the rear of the house on the ground floor, open up the kitchen and reception room into one open plan living area, to refresh the rest of the house which included new plaster skim, doors and frames and to fit new bathrooms and kitchen as well as an rewire on the whole house and the construction of a retaining wall in the garden to accommodate the extension. Florins team were excellent from start to finish, the whole project was completed in record time to a very high standard. The 10 weeks turnaround was incredible, we were very happy that Florin was always here at the property or on the end of the phone throughout the process, his professional advice and smart ideas made for a smooth transition from room to room. The team were very hard working, polite and knowledgeable, these guys worked very hard and very quickly which was amazing to see and I was very grateful we were able to move into the property earlier than planned which even saved us money on the temporary accommodation we had! Can’t thank you enough Florin, any small issues we had were dealt with quickly and smoothly, I love the house, the level of work and would 100% use Florin and his team on my next project!
Marian Disca
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Hi We undertake a variety of work,loft extension,bathrooms,kitchens,roofs,floors.etc With a experience of 15years there’s not much we haven’t done. Reference available!
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Latest review:
Joinery & Cabinet Making- 19 Apr 2019
Marian is i would say a master craftsman . He did an excellent job with the 2 alcove bookshelves. The alcoves were big and i wanted most of the period features and he made it exactly as per my specifications he also helped mount my tv on one of the units and looks very clean and he also helped conceal all wiring for my electric fireplace. I will definitely use his services again.
N.N2 GENERAL BUILDING
No reviews yet
Extension Builder in Welwyn Garden City
General building. EXTENSION, LOFT CONVERSION,GARDENS DESIGN,KITCHEN, BATHROOM, ROOFING,PLASTER &RENDERING, DECORATING, DRIVEWAY, PLUMBING, ELECTRICITY...
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RT Build
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
We are a family run small company with 20 years on the market.We specialize in bathroom ,kitchen and general building refurbishments.We offer high quality service for a reasonable price with great attention to details. Your satisfaction is our top priority.We are looking forward to doing new project with you.
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Latest review:
Bathroom Fitting- 27 Dec 2025
Rafal did everything as expected. Many thanks for his commitment and professionalism.
RNB Construction
No reviews yet
Extension Builder in Welwyn Garden City
RNB Construction are able to offer a complete design and build package for the residential homeowner. We can help clients develop their concepts from ideation, through architectural interface, planning and into a high quality build. We also offer main contracting roles where clients have plans and permissions in place and are just looking for a high quality reliable builder to carry out their project. We were established to bring a professional approach to clientele looking for reassurance
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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.