Extension Builders in Welwyn

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

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Angle Construction
Rating: 4.7 out of 5
Extension Builder in Welwyn
We have been in the construction business for over 15 years doing all sorts of works, from minor works to full home constructions. No job to small no job to big. We work in and around London
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Latest review:
Windows & Doors (uPVC & Metal)- 28 Jan 2026
Very unhappy with how things went with Angle Construction overall. Poor comms during the transaction was the first red flag - no communication for 2 days the moment money was sent, however afterwards received an apologetic call - parts ordered and arrived in due course. Andrei turned up, and got to work on removing the old gate, but then started shaving down the post without saying anything -we were told after that the posts were not level. Eventually he said the door would need to be cut, which we agreed to. The door and posts were both cut to fit, but massive gap left at the bottom, and only half of the door fittings and no handles were installed! In addition, where the door was cut and the wood shaved made, a lot of mess was left all over the garden furniture and patio floor. Shocked at the lack of care and professionalism. He was clearly agitated and in a rush to leave. We have a working back door, but it looks like a real botched job. Not happy, and I would not recommend.
VARTIA BUILDERS LIMITED
New on MyBuilder
Extension Builder in Welwyn
We provide New Builds, reliable Refurbishment and Renovation, and Extension services for homes and properties, with a focus on quality workmanship and attention to detail. We undertake full internal refurbishments including bathroom and kitchen fitting, plumbing, decorating, flooring, plastering, carpentry and general building work. For specialist or regulated work, we use appropriately qualified tradespeople where required. We work closely with our customers from the initial discussion through to completion, keeping communication clear and the work organised. Whether it is a small improvement or a complete property refurbishment, our aim is to deliver a clean, professional finish and a service our customers can rely on. We value the money of our customers and always strive to provide fair pricing, honest advice and long-lasting results.
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Dan’s Team Projects Ltd
No reviews yet
Extension Builder in Welwyn
25 y of experience in building sector. Working as a multi trade person for companies now set up own . Always good communication and problem solving.
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Pascu Building Services
No reviews yet
Extension Builder in Welwyn
Been in the building industry for over 15 years working on a self employed basis, for the past 3 years I am running my own company having different trades subcontracting for me, we mainly deal with general building projects as (house extensions, loft conversions, general refurbishments and house alterations we have a long relation with Waltham Forest Council and Barnet Council as we had a fair amount of jobs in these areas
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Mian builders london limited
No reviews yet
Extension Builder in Welwyn
We are a professional builders
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Uzi Construction Ltd
No reviews yet
Extension Builder in Welwyn
We are a team of reliable, friendly and committed builders. We aim to complete our projects on time and precisely. Our priority is customer satisfaction.
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Ag plumbing & heating
Rating: 5 out of 5
Extension Builder in Welwyn
I have my team builders, plumbers, electricians, plasterers, bricklayer carpenter etc. We do everything from new bathrooms all the way up to extensions and loft conversions. With 10 years experience.
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Latest review:
Plumbing- 18 May 2020
Very quick to sort out, arrived same day to install. All done within an hour Happy with service
Redmark Contractors Limited
Rating: 5 out of 5
Extension Builder in Welwyn
Redmark Contractors Limited have over 10 years experience, and with many years experience in the building trade. We are a professional team are reliable builders operating in London and the wider area. We take great pride in all work which we undertake, taking great care to make sure that our client’s needs are met in a meticulous and professional manner.
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Latest review:
Extensions- 27 May 2025
They helped build me two houses and were always putting their best foot forwards. Bhupinder and his team are lovely, and are now like family to me. They have a bright future ahead for themselves and for the clients they look after.
mbond
No reviews yet
Extension Builder in Welwyn
Our team undertake building projects for last 15 years in London and surrounding areas - we doing lots of HI-end bathrooms and kitchens ,extensions ,loft conversion and general refurbishment works. We can provide references from our clients plus its always possible to visit one of our current projects or in some cases past projects as well.
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Bespoke Builds by JFN
No reviews yet
Extension Builder in Welwyn
Bespoke Builds by JFN delivers comprehensive building and home improvement services, specialising in loft conversions, home extensions, kitchens, and bathrooms. From full renovations to day-to-day maintenance and carpentry, we manage projects with precision, transparency, and a commitment to exceptional workmanship. We take pride in delivering reliable service, smooth project management, and quality finishes designed to stand the test of time. Your space, built better
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Andrei
No reviews yet
Extension Builder in Welwyn
My occupation building. I am working carpenter 5 years. I building loft conversion Extension any first and second fix.
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Nelson and Sons General Builders
No reviews yet
Extension Builder in Welwyn
We are general builders taking on extensions, bathrooms, kitchens. All trades covered. All our work is guaranteed and finished to a very high standard.
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N. G. IONITA
No reviews yet
Extension Builder in Welwyn
With over 13 years in the trade undertaking all sorts of works from ground works to roof works we have been shifting throughout all the works that involves building a house, yet we might not have achieved the best knowledge in plumbing and electricity be rest assured that we can still provide advice, accommodate and protect other peoples work in your project.
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Harinder singh
No reviews yet
Extension Builder in Welwyn
Hi, I’m a skilled and reliable restoration and refurbishment specialist with over 12 years of experience in the industry. I run H.S. Builders, a trusted name in East London and Essex, known for delivering high-quality work across a wide range of services – from chimney removals and structural alterations to plastering, painting, kitchen and bathroom renovations, and full property refurbishments. At H.S. Builders, we focus on doing the job right the first time, with attention to detail, honest pricing, and clear communication throughout. Whether it’s a small update or a full-scale renovation, we’re committed to making your vision a reality. Get in touch today for a free quote or friendly advice on your project.
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Star link
No reviews yet
Extension Builder in Welwyn
I have experience team for all types of construction work
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Gill Builder
No reviews yet
Extension Builder in Welwyn
I am always available for electricity, plumbing, house renovation, floor heating, extension, driveway, garden work etc. No Job is small for me and I always do my job with dedication. I have more than 10 years of work experience in construction line. note: - free quotation for work.
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3.9

Top rated Extension Builders

Our Extension Builders in Welwyn, 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?

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 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 who are available and interested can respond to your post.

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

What are the hourly rates of extension builders in Welwyn?

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

Find extension builders in Welwyn with MyBuilder

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

Step 2: Compare different extension builders in Welwyn

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

Step 3: Hire Welwyn extension builders with confidence

After gathering all the information and quotes from your chosen home extension builders in Welwyn, 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 extension builders are ready to help. Use MyBuilder today to find the right professional for your home extension.

What to ask a Welwyn extension builder before hiring?

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

An extension builder in Welwyn 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 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?

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 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 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

Can an extension builder in Welwyn help with planning permission?

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

Many Welwyn 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 help with materials and finishes?

Yes, most extension builders in Welwyn 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.