Extension Builders in Hertfordshire

Name: Extension Builder
Brand: MyBuilder
SKU: extension-builder
Rating: 3.9 (15 reviews)

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Some of our top rated extension builders in Hertfordshire

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Eco-property group
No reviews yet
Extension Builder in Hertfordshire
Eco property group We take on all building work mainly domestics new builds extensions loft conversions renovations swimming pools All internal finishes To which ever the clients requirements to extremely high standards. We also do landscaping drive ways We do try to use as much eco-products as possible for our builds. Down to energy-efficient electrics Air source heating ground source heating. Bor Holes for own water source Minimise as much waste as possible
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Solid building aspect Ltd
No reviews yet
Extension Builder in Hertfordshire
Solid Building Aspect Ltd is a specialist construction company delivering high-quality residential and commercial projects across London and Hertfordshire. With over 20 years of industry experience, we focus on extensions, structural alterations, renovations, and modern steel frame (SFS) systems — offering a more precise, efficient, and reliable way to build. We also design and build bespoke garden rooms and install premium aluminium and composite decking systems, creating functional, modern outdoor spaces tailored to each client’s needs. Our approach combines strong project management, attention to detail, and clear communication from start to finish. Whether transforming a home, adding flexible living space, or delivering complex structural works, we focus on results that add real value and stand the test of time.
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Cosybuild ltd
No reviews yet
Extension Builder in Hertfordshire
Cosy Build is a new chapter in our journey, rebranding after over 10 years of trusted building and construction expertise across Harpenden, Radlett, Hertfordshire, North London, and surrounding areas. Based in Hertfordshire, our professional, reliable tradesmen serve St Albans, Harpenden, Radlett, North London, and nearby regions, delivering high-quality building services with a commitment to excellence. Formerly known as Luan Ajazi Home Improvements. Cosy Build is a family-run, customer-focused building company with deep roots in the Hertfordshire and North London construction industry. Our team consist of: Highly skilled craftsmen with decades of combined experience. Fully insured and certified professionals for your peace of mind. Local experts who understand the architectural styles and regulations of the area. What We Do & What We Care About Cosy Build is a family-run, customer-focused building company with deep roots in the Hertfordshire and North London construction industry. We specialise in: Loft conversions – Maximising your home's space and value. Loft conversions – Maximising your home's space and value. Home extensions – Seamlessly blending new spaces with your existing property. Renovations – Modernisin
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ReformWorks Design Limited
Rating: 4.8 out of 5
Extension Builder in Hertfordshire
ReformWorks Design Ltd We have been in the building industry for more then 25 years. we refurbish huoses and build extensions your project can be as small as a kitchen or bathroom, or as large as a complete renovation
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Latest review:
Extensions- 19 May 2026
Very good builder, done a good job. You can 100% trust him to do the job.
Home Comfort Design & Build Ltd
Rating: 4.9 out of 5
Extension Builder in Hertfordshire
Home Comfort Design and Build Ltd have many years’ experience in both commercial and private property renovations specializing in Extensions, House refurbishment, Loft and Garage conversions, Driveways and Patios. We offer a full range of services from Architectural and Structural design to dealing with Council planning applications. Please get in touch for a friendly free-of-charge no obligation consultation. Many thanks, Graham
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Latest review:
Bathroom Fitting- 14 Nov 2019
We had our bathroom completely refurbished and Graham the owner was lovely. He came to give us the quote, visited whilst work was being undertaken to make sure everything was okay and came to make sure everything was finished to how we wanted it. The work carried out was of a high standard and whilst the bathroom work was being completed we also ended up getting our kitchen worktops done by Graham’s team. Chris was the one who carried out our work, he was very friendly and checked we were happy with the work he’d done before he left everyday. I would use Graham again for other work needed around the house.
JHF Construction Limited
Rating: 5 out of 5
Extension Builder in Hertfordshire
JHF Construction Ltd have been established as a limited and VAT registered company since March 2018. Located on the outskirts of Hitchin, our brand-new Studio is an example of our work and welcomes visits. We provide a reliable, professional service with innovative concepts and pride ourselves on the quality of our work. We offer everything from design through to completion and work hand-in-hand with our clients to ensure expectations are met and exceeded. Always striving to go the extra mile.
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Latest review:
Kitchen Fitting- 27 Feb 2019
Jack and the team did a great job on our new kitchen including new electrics, tiles and underfloor heating and we’re truly delighted with the end result. Jack was always available to discuss the project and answer any questions or concerns I had and was able to quickly overcome issues we experienced relating to the kitchen units and a design error. He was always professional and gave us useful tips and input into the overall kitchen design and helped us source very nice materials. As with many small businesses, Jack and the team were juggling other jobs along side ours which meant that after some unexpected additional work on our floor, they were unable to complete the job within the original timeframe plus 2 days contingency. As a family with young children we found this really difficult so I would urge you to project manage closely. It was all totally worth it in the end though and overall I would recommend Jack and the team.
KCK Renovation
Rating: 5 out of 5
Extension Builder in Hertfordshire
I have been involved in the building industry for over 15 years with an extensive portfolio of renovated properties across London. My background comes from interior design which has lead me over the years to develop a great eye for interior architecture which has therefore abled me to give my clients innovated and creative ideas for all their property needs,Within our work quality and design is key.
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Latest review:
Extensions- 25 Apr 2018
Initially when using My Builder, I didn’t really have any intentions of working with tradesmen from here, it was more to benchmark and see where a quotation would be priced however upon meeting Vijay, that pretty much changed from the first meeting. If you’re looking for someone who treats your project like their own, he’s the man. Vijay takes 110% pride and care into every aspect of your project. Although work is yet to commence on my property, the spec Vijay has put together itself is worth a lot of money, and most would consider it invaluable. From my opinion so far, no stone will be left unturned where Vijay’s project management and work is concerned. Without thinking twice, I would highly recommend anyone considering Vijay, to at the very least, meet with him and show him the work required. From there on, your mind will be made up. Looking forward to working with him in due course
D&A BRICKWORK/BUILDING
Rating: 5 out of 5
Extension Builder in Hertfordshire
Hi, let me introduce myself im Des Treanor Of D&A BRICKWORK/BUILDING FEDERATION OF MASTER BUILDERS MEMBER OVER 42 100% REVIEWS AT CHECKATRADE We carry out all related building and structural rsj works: EXTENSION CONVERSION REFURBISHMENT STRUCTURAL RSJ WORK ALTERATIONS ALL RELATED HARD LANDSCAPING if you feel we can make your dream become a reality please feel free to contact me. Many thanks, Des.
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Latest review:
Groundwork & Foundations- 5 Aug 2024
Des and Steve did an outstanding job digging for the foundation and pouring the concrete. They were professional, very tidy, and friendly throughout the process. I also want to express my appreciation for their plumber, Tony, who did a great job redoing the connection to the old cast iron water supply pipe and moving the stopcock. Their combined efforts were impressive and much appreciated. Now waiting for them to carry on with thd brick work.
HadleyWoods
Rating: 5 out of 5
Extension Builder in Hertfordshire
HadleyWoods provides the highest quality services for your home, office or commercial building. With more than 25 years experience we have many regular customers who would highly recommend us as a professional and respected service, our secret to this success is purely based on employing only the best workers with years of experience and attention to detail.
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Latest review:
Restoration & Refurbishment- 9 Nov 2024
Hasan did a good job removing my 2 chimney breasts. Quick and professional, will definitely use him again for future works
Gh building
No reviews yet
Extension Builder in Hertfordshire
Gh building have over 25 years of building experience, completing a variety of projects. All brickwork undertaken. Ground works Driveways Extensions Garden walls Landscaping
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HR RENOVATIONS
Rating: 5 out of 5
Extension Builder in Hertfordshire
HR Renovations cover all aspects of building renovations.
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Latest review:
Painting & Decorating- 2 Jul 2025
Would highly recommend HR Renovations. A massive thank you to Ben and his team. They did a fantastic job of renovating my house and I would definitely be using them again! I would highly Recommend HR Renovations.
Cekamaintenance ltd
Rating: 5 out of 5
Extension Builder in Hertfordshire
With over 20 years in carpentry, plumbing, kitchen and bathroom fittings, and general building maintenance work.
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Latest review:
Carpentry- 2 Aug 2025
Excellent service from start to finish, tradesman as they should be!
G.I.K SERVICES LTD
Rating: 5 out of 5
Extension Builder in Hertfordshire
G.I.K SERVICES LTD company is the best variant for you if you need any home renovation, flat remodelling or refubrishment. We undertake any kind of work for your property. We have the best team of experts, that have required experience and can take up each renovation project. If it’s already started – we will finish it.
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Latest review:
Painting & Decorating- 31 May 2023
Great job - very professional and came over at a moments notice - highly recommended
Marian Disca
Rating: 5 out of 5
Extension Builder in Hertfordshire
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.
The little joinery co
No reviews yet
Extension Builder in Hertfordshire
Bespoke building company based in Harpenden. Regularly completing one of a kind extensions, loft conversions and development projects to a high standard.
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D&E Smart Building Solutions Ltd
Rating: 5 out of 5
Extension Builder in Hertfordshire
Loft conversion. New or refurbished extension. All Carpentry work. New decking or refurbished. Brick walls front of the house, or new building. New or refurbished bathroom, Tilse, Garden, Kitchen, Wood floor, Plumbing with certificate, Electrical with certificate, and much, much more..
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Latest review:
Bathroom Fitting- 7 Mar 2022
Daniel was great and we were impressed by the level of care and detail in his work. Would use him again and recommend to friends.

3.9

Top rated Extension Builders

Our Extension Builders in Hertfordshire, are rated 3.9 out of 5 based on 15 reviews from customers like you.

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What types of services are offered by local extension builders in Hertfordshire?

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 Hertfordshire 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 Hertfordshire who are available and interested can respond to your post.

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

What are the hourly rates of extension builders in Hertfordshire?

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

Find extension builders in Hertfordshire with MyBuilder

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

Step 2: Compare different extension builders in Hertfordshire

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

Step 3: Hire Hertfordshire extension builders with confidence

After gathering all the information and quotes from your chosen home extension builders in Hertfordshire, 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.

Hertfordshire extension builders are ready to help. Use MyBuilder today to find the right professional for your home extension.

What to ask a Hertfordshire extension builder before hiring?

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

An extension builder in Hertfordshire 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 Hertfordshire 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 Hertfordshire?

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 Hertfordshire 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 Hertfordshire 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 Hertfordshire

Can an extension builder in Hertfordshire help with planning permission?

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

Many Hertfordshire 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 Hertfordshire help with materials and finishes?

Yes, most extension builders in Hertfordshire 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.