Extension Builders in Welwyn

Name: Extension Builder
Brand: MyBuilder
SKU: extension-builder
Rating: 3.7 (13 reviews)

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Some of our top rated extension builders in Welwyn

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Highpoint roofing and building contractors
Rating: 5 out of 5
Extension Builder in Welwyn
At Highpoint roofing and building contractors we have over 40 years of experience Collectively, we take pride in our work to ensure 100% customer satisfaction With our free no obligation quotation you will be given all the advice you need to ensure total piece of mind our goal is to meet and exceed expectations of every customer all work carried out to the highest Possible standards and at very competitive prices
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Latest review:
Roofing (Flat)- 6 Jan 2026
Completed the job as promised and was very tidy in his job
Castle Wren Ltd
No reviews yet
Extension Builder in Welwyn
We began our journey in groundwork, and while it’s still a big part of our business now - over the years we have built an end to end construction firm. From demolition and site enablement to extensions and even small developments, we have the expertise and the equipment to take on all of the projects our clients bring. We are members of the Federation of Master Builders, the government backed Trustmark scheme and are Trading Standards approved. Here in Hertfordshire, a huge part of our work is also in gardens, building walls, laying turf, patios and driveways and it’s something we take huge pride in.
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1789design limited
No reviews yet
Extension Builder in Welwyn
We are a small construction company that deal with loft conversions, extensions, structural work, refurbishing, electrical(with certificate), plumbing as well as bathroom work, kitchen fittings, wood floor, tiling, drainage, patios, driveways, outhouses, new building etc. 17 years of experience in improving customers comfort. Many satisfied customers along the years. References available upon request( some projects can be seen). We are looking forward in working with you, all work is contract based, we are fully insured for the work we do.
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Rumahn International
No reviews yet
Extension Builder in Welwyn
With over 35 years of experience in the building industry, we offer a complete A–Z service across all trades — from builders, carpenters, fitters, and bricklayers to electricians, plumbers, and more. Whether it’s a minor repair or a major development project, we provide trusted professionals for every job. At Mazmo, we pride ourselves on delivering exceptional service, reliability, and peace of mind. Our “one-stop shop” approach means you don’t need to look elsewhere — we handle everything under one roof. Quality workmanship. Proven expertise. All in one place.
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Complete construction Ltd
New on MyBuilder
Extension Builder in Welwyn
We are a reliable and experienced building company providing a wide range of property improvement and renovation services. Our work includes roofing, ceilings, kitchens, flooring, general building, maintenance, and refurbishment projects for residential and commercial clients. We take pride in delivering high-quality workmanship, professional service, and projects completed to a high standard, on time and within budget.
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REDFERN DRYWALL LIMITED
No reviews yet
Extension Builder in Welwyn
REDFERN DRYWALL - Extensions, Refurbishment and Conversion specialists. Recent projects include: St Marys church - Sloane square, London. St Katharine's church - Ickleford, Hitchin. Berrywood Hospital - Northampton. Alexandra primary school, Wood green, London. Residential Units/Homes, Hertfordshire, Buckinghamshire & Bedfordshire. Other Services provided. Conservation - Lime Render, Lime plaster. Specialist Cornice Manufacture/Repair Colour through render systems. Floor screeds. Loft/Garage conversions. Basement Conversions. New Build & Extensions. Assistance with planning applications and drawings. Fully Insured. H&S compliant. We pride ourselves on delivering high quality workmanship. We only work with trusted highly skilled tradespeople ensuring your project is finished on schedule and to the highest standards.
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Halls construction
No reviews yet
Extension Builder in Welwyn
I'm a builder with 28 years experience. I specialise in extensions and loft conversions. I'm honest and hard working. I take pride in my work and ensure its of a high standard. I'm multi skilled so I'm able to build most aspects of a project myself. That way I can guarantee the quality of the work. Most of my work comes from word of mouth. I get lots of recommendations from previous customers. I'm hoping to increase my workload by advertising here. I've got a large portfolio of work and previous customers that will give good references.
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Bjoldi Construction
No reviews yet
Extension Builder in Welwyn
Bjoldi Construction is a trusted construction group with over 10 years of experience delivering high-quality building solutions. Our expertise spans across residential, commercial, and industrial projects, ensuring precision and excellence in everything we do. From initial planning and design to construction and project management, we are committed to exceeding client expectations with attention to detail, skilled craftsmanship, and a focus on safety and sustainability. Whether it’s a small renovation or a large-scale development, we have the knowledge, experience, and dedication to bring your vision to life.
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Aaron h construction ltd
No reviews yet
Extension Builder in Welwyn
Hi there,we are building company we Been in the building business for 15 years we are specialised in extension loft conversation and House refurbishment. pls give us a call happy to help
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North London brickworks ltd
No reviews yet
Extension Builder in Welwyn
I’m reaching out to introduce North London Brickworks Ltd, a professional bricklaying company based in North London. We specialize in all aspects of brickwork, including new builds, commercial, and residential projects. With a skilled team and a commitment to high-quality workmanship, we ensure every project is completed to the highest standards. We would love the opportunity to discuss any upcoming projects where our services could be of value.
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Allsop Design and build
No reviews yet
Extension Builder in Welwyn
New up and coming building company to help with all your needs
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CALLAN GROUP LTD
No reviews yet
Extension Builder in Welwyn
Our team are on hand from start to finish, working alongside professionals to ensure seamless communication, on-site organisation and solid, quality work every time. From architects, bricklayers, groundworkers, electricians, plumbers, to renderers, painters and decorators. Your project is guaranteed to be completed over and beyond your expectations.
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NEWVIBEHOMEIMPROVEMENTS
No reviews yet
Extension Builder in Welwyn
"We are a comprehensive home transformation company specializing in high-quality extensions, full property refurbishments, kitchens, and more. While we handle every aspect of your build from the ground up, we are true specialists in luxury bathroom fitting and wet room installations.
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Adrian Popa
No reviews yet
Extension Builder in Welwyn
Hi . I can undertake loft conversions extension s , carpentry, bespoke furniture, plumbing, electric, full refurbishment.
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Eagle brickwork
No reviews yet
Extension Builder in Welwyn
I’m a skilled bricklayer with years of hands-on experience in building high-quality extensions and new builds. I take pride in delivering reliable, precise, and long-lasting workmanship on every project. Whether it’s a small home addition or a full property build, I ensure every job is completed to the highest standard, on time and within budget. Customer satisfaction and attention to detail are at the heart of everything I do.
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R Hamandi Limited
Rating: 5 out of 5
Extension Builder in Welwyn
R.Hamandi Limited was established in January 2010 and firm in London, providing construction management, general contracting and consultant services. RHL specialises in construction and restoration of private and commercial sector in the heart of London including Residential refurbishment,Commercial,New build,Design and build, Basement construction, Kitchens specialists, Listed buildings, Sustainable buildings
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Latest review:
My colleague referred me to Raed who previously have had used R.Hamandi Ltd for construction work and they were very happy with the quality of service. Along with some other building company's last year I also contacted Raed for an estimate. Raed gave us a reasonable price with all the details of proposed work. He also explained about the possible options of how we could get the best value for our money. His professional and friendly advice helped us a lot to understand what exactly we needed and what was best for us to go ahead for our project. We decided to go ahead with R.Hamandi ltd. Raed gave us breakdown of the project and everything was documented. His support in communicating with council and planning related issues was valuable. All the planning permission requirements were followed. Presence of experienced and trust worthy staff including laborers, handymen, carpenters and painters really made it easy for me and family to be around and comfortable while they were working or to leave the house whenever we had to. Raed himself used to visit the site everyday to oversee the progress and used to discuss and take care of any possible issues. Raed's team used to turn up on time and the project was finished on time too. Even after the completion of the project staff at R.Hamandi ltd and Raed himself contacted us few times to find out if we're happy with the work carried out or if we needed any further assistance. Now we have a fully refurbed house with double side extension and loft conversion. Overall amazing service, professional, reliable and trustworthy. I recommend R.Hamandi ltd to everyone for an A+ service. Thanks,

3.7

Top rated Extension Builders

Our Extension Builders in Welwyn, are rated 3.7 out of 5 based on 13 reviews from customers like you.

Quality screening

Easily find verified local tradespeople. Just post your job to get quotes from tradespeople near you across the UK.

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.