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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Jessieva Ltd
No reviews yet
Extension Builder in Welwyn Garden City
Recommended company on the market who does the job no matter the size.Well established company with houndreds jobs recommendations ,high valuable teams and one of the best for reacting.Trusted and recommended for small jobs(kitchen ,bathrooms refurbs),medium jobs(lofts,extensions) and bigger jobs(new builds or commercial)
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Mbalau Construction LTD
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Builder with 20 years of experience . I provide a wide range of building services such as: loft conversion, extensions,bathroom refurbishment,house refurbishment , plumbing and electric etc . I have the tools,knowledge and team to build a house from start to finish . I can provide references and pictures of previous work upon request .
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Latest review:
Complete refurbishment of 2 bed 1100 sq ft flat. Including removal internal walls Ripping out and renovating 2 bathrooms. Involving new layout replumbng and relocation of #electrics. Tileing Preparing and laying wood flooring throughout. Fitting shelving and book case. The work over 2 months involved all building skills. Throughout Marcel and his highly skilled crew were efficient clean and resourceful. I would highly recommend for all building and decoration work.
Shpetim troka
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Troka Construction specializes in home refurbishments, extensions, and a wide range of home improvements. With a focus on quality craftsmanship and personalized service, we bring our clients' visions to life with dedication and attention to detail.
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Latest review:
Carpentry- 30 Apr 2026
Great communication and was able to come and do the job quickly after first message. Job was completed to a great standard (skirting boards and some scotia)
Dignity LC Services Ltd
No reviews yet
Extension Builder in Welwyn Garden City
I have been running my own building and construction business for approx 30 years, with over 35 years of industry experience. I am a fully skilled carpenter by trade but have vast amounts of knowledge and experience in all aspects of building and construction works. The work I undertake includes domestic building; extensions, conversions, kitchens and bathroom, disabled adaptations.
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T.H Brickwork
No reviews yet
Extension Builder in Welwyn Garden City
I specialise in all aspects of brickwork ie: House building, extensions, garden walls, pointing, brick bbq’s and repair work. I also specialise in patios and landscape gardening.
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KASE Construct limited
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
KASE Construct is a family owned business, with a 30 year legacy in construction. Our team are passionate and highly experienced. Professionalism and consistency in customer service is very important to us, going above and beyond in everything we do. Work we undertake: Roofing, loft conversions Extensions Refurbishments / re modelling New builds and Retrofitting Painting and Decorating Polished and Traditional Plastering Carpentry Kitchens Bathrooms
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Latest review:
Plastering- 10 Oct 2022
Very positive - Lee did a superb job, was on time and a pleasure to deal with. I'd highly recommend him
Josh
No reviews yet
Extension Builder in Welwyn Garden City
Hi we're honest reliable builder's and take on all aspects of building groundworks and landscaping
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Faton
No reviews yet
Extension Builder in Welwyn Garden City
Trust and honest
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Michael John Interiors
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
Hi I'm a general builder, started my working life on kitchen & interior design then also Installations, which quickly lead to building works. Taking down walls to building large extensions/loft conversions & out side works We take on any size work & can offer lots of advice & design help, having 35 years experience From kitchen installations & all types of Interior work To extensions/outside works & loft conversions.
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Latest review:
Extensions- 15 Apr 2019
Submitted quote on time and has responded to all questions and been very helpful.
PWF CONSTRUCTION LTD
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
FRIENDLY, POLITE AND CONSCIENTIOUS
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Latest review:
PWF construction were never hired to complete my job and the fact that I am now writing a review is an error on my part. Paul Fisher was however very helpful when he provided a quotation for my job and his communication was great.
Majesticbuild
Rating: 3 out of 5
Extension Builder in Welwyn Garden City
At Majestic Build Construction Company, we don’t just build structures; we craft environments that blend seamlessly with nature. With a passion for creating breathtaking outdoor spaces, our landscaping services are designed to enhance the natural beauty of any property, be it residential, commercial, or public. We specialize in: • Custom Landscape Design: Tailored to suit your vision and the unique features of your land. • Hardscaping Solutions: Including patios, walkways, retaining walls, and water features that add depth and functionality to your outdoors. • Sustainable Landscaping: Focusing on eco-friendly practices and native plant selections for a greener future. • Comprehensive Maintenance: Ensuring your landscapes remain as vibrant and immaculate as the day they were created. With a dedicated team of professionals and a reputation for excellence, Majestic Build Construction Company transforms ordinary spaces into extraordinary outdoor experiences. Let us bring your landscaping dreams to life!
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Latest review:
Bricklaying- 17 Dec 2024
They initially gave a fair price and a date and timeline that fitted with our needs. Subsequently they over ordered on the bricks so we had over 100+ expensive London bricks left over and they under ordered on sand and cement.(Luckily the shop took them back but we had to deliver them there) The job took far longer than they had said although the poor weather did not help much which could not be helped. The worst was that the wall was finished so that the latch of the gate could not be fitted as the wall was a bit too long! The wall looks good but their customer service and time given for job as well as ordering materials needs some improvements. They are pleasant workers, not rude in speaking
HWA Building & Renovations
No reviews yet
Extension Builder in Welwyn Garden City
My Dad and I set up the company at the beginning of this year with ambition of building our own company, instead of working for others. We work in Hertfordshire, North London, Essex and Lower Bedfordshire. My dad has worked in construction for over 30 years, doing surveying for main contractors, as well as his own property development projects. I have now completed my degree apprenticeship in construction quantity surveying achieving a building science second class honors. I have also ran my own jobs for a main contractor in London and surrounding areas worth up to £4 million. Our lads on the tools all have CSCS cards, and have achieved the relevant carpentry qualifications. We specialize in bespoke garden rooms with our in house labor, and build extensions, refurbs, conversions, and new builds.
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N Flack building services Ltd
No reviews yet
Extension Builder in Welwyn Garden City
I’m very good builder with 30years experience. I work all over north London and Hertfordshire. I’m a multi trader also with a team of experienced tradesmen to cover all areas. You can find my business on facebook and instagram.
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ROSSIS CONSTRUCTION LTD
Rating: 4.9 out of 5
Extension Builder in Welwyn Garden City
FMB member
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Latest review:
Extensions- 24 Feb 2020
Rosin was fully committed to the job from the beginning. His pricing was reasonable and the building work was professional. His time keeping was 100% with outstanding work ethics. Highly recommend.
BTL Building & Landscaping
Rating: 5 out of 5
Extension Builder in Welwyn Garden City
BTL Building & Landscaping – Creating Timeless Spaces, Built To Last At BTL, we specialise in transforming outdoor & indoor areas into extraordinary spaces that reflect elegance, functionality, and timeless appeal. Whether it's a luxury garden retreat, a bespoke outdoor living area, or a comprehensive property renovation, our building and landscaping services are designed to exceed expectations—every time. Crafted for Excellence We are not just builders or landscapers—we are artisans of space. Our mission is simple: to deliver high-end solutions that not only elevate properties but enrich lifestyles. From concept to completion, we bring a level of precision, care, and craftsmanship that sets a new standard in the industry. Each project we undertake is treated as a unique expression of our client’s vision. Our team collaborates closely with homeowners, architects, and developers to ensure every detail aligns perfectly with your goals—whether you’re seeking to increase property value, create a stunning visual statement, or build a sanctuary for everyday living. We would love to part of your journey creating spaces you thought you could only dream of. BTL Building & Landscaping Creating Timeless Spaces, Built To Last
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Latest review:
Landscaping- 2 Jun 2025
Excellent, best decision I made, Ollie, Scott & Ryan did an excellent job. They have an eye for detail and take pride in what they do. Couldn’t have asked for more.
Added Space
Rating: 3.7 out of 5
Extension Builder in Welwyn Garden City
After gaining my NVQs in Brickwork and Health and Safety in College 16 year's ago, I have worked hands on ever since. Building up a great portfolio along the way. No job to big or small. Competitive Pricing and Quality of work is very high.
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Latest review:
Bricklaying- 15 Jul 2019
I can’t recommend Chris enough. Polite & Professional. I was away for the weekend and came back to no mess or issues. Chris completed the wall on time and to cost quoted. So much so he will be quoting on further work for me. Highly recommended.

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.