Extension Builders in Harrow

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

Easily find verified Harrow Extension Builders. Just post your job to get quotes from MyBuilder's Extension Builders in Harrow.

Select a service

How it works

Post your job for free

Tell us about your job, and we’ll alert suitable tradespeople in your area. It’s simple and free.

Tradespeople respond

Once your job is posted, you’ll get responses from interested tradespeople through the website.

Review profiles and choose

Browse profiles, work history, and feedback, then choose who you wish to share your details with.

Some of our top rated extension builders in Harrow

3043 Results

Sort by:

3 Enterprise Limited
No reviews yet
Extension Builder in Harrow
With over 30 years of industry experience, we deliver high-quality construction services built on trust, expertise, and attention to detail. Our team specialises in providing reliable solutions tailored to each client's bespoke needs. Committed to excellence, we combine traditional craftmanship with modern techniques to ensure lasting results
Get in touch
Jk home refurbishment
No reviews yet
Extension Builder in Harrow
Loft conversion,Extansions,Bathroom,kitchen, Tilling,Plumbing,Electrical,Brickwork,Plastering Flooring
Get in touch
Allsetconstruct
No reviews yet
Extension Builder in Harrow
Allsetconstruct is a professional team with many years of experience for all types of ground and building work: extensions, drainage and pipe layer, interior refurbishment, driveways and patios, landscaping.
Get in touch
CM Building LTD
Rating: 5 out of 5
Extension Builder in Harrow
At CM Loft Conversions, we specialise in luxury loft conversions, home extensions, and full refurbishments for both residential and commercial properties across London. Our dedicated team is renowned for transforming spaces with unparalleled craftsmanship and meticulous attention to detail. Whether it’s a high-end home, a modern office, or a commercial property, we deliver projects that elevate both form and function. By seamlessly blending design innovation with practical solutions, we ensure every project not only enhances the aesthetic appeal of a space but also maximises its value and usability. At CM Loft Conversions, we are passionate about creating bespoke spaces that reflect the unique needs of our clients. From concept to completion, we focus on the fine details and provide a smooth, stress-free experience. Whether you’re looking to transform your home, expand your business premises, or refurbish a commercial unit, our team is committed to delivering results that exceed expectations.
Get in touch
Latest review:
I met Charlie and his team from CM Builders Ltd when they were completing a loft extension and ground floor extension for one of my neighbours. Quotation and budget I was given an estimate subject to drawings as I was on a strict budget that I had to keep to for the build. Charlie was able to help me keep to the budget, both at the final agreed plan and during the build. The project was complex in that whilst it was a loft extension, all of the house was rebuilt. The only thing kept was the external walls and first floor rafters. Whilst the footprint of the first floor was not being changed I wanted to bring it up to current building standards with extra insulation. All of the plumbing and electrics were also replaced including a new boiler. The overall build has come in on budget, save for agreed enhancements that I did not think of at the planning stage and or building regulations such as double ceiling fire plaster boards. There were also items such as the original stairs that I wanted to keep, but Charlie was able to increase the height space in the kitchen making the worktop much more usable for tall people for a larger part of the kitchen. These were suggested to me as potential options as part of the build. Stage payments The stage payments have all been sensible throughout the build and linked to the ongoing work schedule. I have not therefore had any concerns in this regard. Quality of work This was a very complicated build as unlike the ground floor the first and new second floor are “L” shaped. The new 2nd floor included an en-suite and 2 bedrooms. Overall the house has been increased from 2 bedrooms 1 bathroom, to four doubles and 2 bathrooms. The quality of work is excellent and Charlie project manages his team to ensure that they all deliver to a high standard- if it is not done correctlt they do it again, with Charlie spotting any issues. Timeline of build This has generally gone to plan very well. As with any build you have to be realistic as things will happen outside of anyone’s control. When issues have arisen Charlie manages them to a conclusion. Also be realistic if you are having to manage to a tight budget. I had to plan for various stage receipts of cash before I could order the kitchen and bathroom items - make sure you understand how this impacts the build and availability of the work force, recognising that CM Builders have to book kitchen fitters and plumbers. CM Builders are also very helpful in that they have sorted out issues with the brick work of my freestanding garage (nothing to do with the build) and also a neighbour’s wall that could have been dangerous to the public, should it have failed. Conclusion The whole family are very pleased with the outcome and we now have the equivalent of a brand new house that has been built to a very high standard. This has definitely been worth doing both from a valuation perspective and quality of life perspective. I would not hesitate to instruct Charlie and his team again.
SEASOUTH BUILDS LIMITED
Rating: 5 out of 5
Extension Builder in Harrow
At Seasouth Builds, we bring over 5 years of hands-on experience in the building and construction industry. Known for our loyalty, reliability, and attention to detail, we take pride in delivering high-quality workmanship on every project
Get in touch
Latest review:
Tiling- 24 Sep 2025
I hired seasouth builds because not only did he give a really reasonable quote, but he also had knowledge of tiling over retrofit underfloor heating - which other tilers seemed to be really hesitant to work with. The job was done to an excellent standard - he’s a real perfectionist. It did take a bit longer than expected, due to some floor level issues which he didn’t account for when he quoted. I was really worried about the price increasing out of my budget when we started running over time, but I was so grateful to find that he was a really honest guy who stuck to the agreed quote and didn’t try to make it my problem one little bit. He was polite and friendly throughout the whole job, turned up whenever he said he would, and kept in constant contact. Really honest (I happily left him unattended in my property). Customer service was excellent, nothing was too much trouble. 10/10 would recommend.
Sc brickwork
No reviews yet
Extension Builder in Harrow
Extension landscaping brickwork and all building work undertaking
Get in touch
Darktolight
Rating: 4.5 out of 5
Extension Builder in Harrow
WELCOME to DARK 2 LIGHT CONSTRUCTION LTD. We are team of builders and electricians and all the trades . Our website is available to get more information ! Our team is made up of qualified, trusted and experienced workers . No job is too small or too big, we offer a big range of services . Call now to get a free quote !
Get in touch
Latest review:
Extensions- 14 Jun 2023
⭐️⭐️⭐️⭐️Excellent Builders.👍👍⭐️⭐️⭐️ I used different types of builders for the past 10yrs for various type of job. But I would tell DARKTOLIGHT are THE BEST of all. They are skilful, honest, punctual, friendly, economical, and very professional. They always consider your financial situation and help your building/repair needs accordingly. They complete the job with the fullest satisfaction on time. I have already booked for more of my other jobs. Highly recommend.10/10.
Shivprem Ltd
No reviews yet
Extension Builder in Harrow
10 Years experience. Experienced in new builds, refurbishments.
Get in touch
Leka constriction
No reviews yet
Extension Builder in Harrow
Hello.. im Leka construction ltd My services are: new building,extensions,tiles,bathrooms,painting and decoration,refurbishment etc
Get in touch
NW7 construction
No reviews yet
Extension Builder in Harrow
Hi, my name is Ivan. I live in UK 24 years. I always been at in construction business
Get in touch
H S CONSTRUCTION LONDON LTD
Rating: 5 out of 5
Extension Builder in Harrow
HS construction is a reliable business based in Berkshire/West London covering all aspects of building work. Established since 2009, HSC has worked with many homeowners and architects to deliver high-quality structures across London and home counties . HSC are a registered and fully insured business ready to take on projects no matter how big or small . We offer a free no obligation quote and a site visit prior to quotation as well as having many links with experienced architects .
Get in touch
Latest review:
I have been using HS Construction London for many years ranging from a full house refurbishment to smaller unexpected issues. I have always found them to be reliable and genuine. There are never any hidden surprises in the end. Sunny listens to his customers and also gives decent advice where needed. Their work is of quality and has a long life. I particularly impressed with how they complete the job in a timely manner. All the materials that have been used are of great quality; and it shows. In addition, HSC has many contacts such as architects, suppliers etc which has made my life so much easier. Reasonably priced and with great knowledge, i would certainly use them again.
Luxatti homes ltd
No reviews yet
Extension Builder in Harrow
Building Luxury, Perfecting Detail At Luxatti Homes Ltd, we bring over 15 years of experience delivering high-end residential construction, bespoke new builds, extensions, and full refurbishments across London and the Home Counties. Led by Satwinder (Sunny) Johar, our team combines craftsmanship, innovation, and reliability — treating every home as if it were our own. We cover West London, Buckinghamshire, Berkshire, Surrey, and Middlesex, including Gerrards Cross, Beaconsfield, Maidenhead, Wimbledon, Uxbridge, Hayes, and surrounding areas. Our expertise includes luxury new builds, loft conversions, kitchen and bathroom installations, glazing, roofing, underfloor heating, and complete project management under JCT standards. Clients choose Luxatti Homes for our attention to detail, transparent communication, and flawless delivery. Every project reflects our belief that true luxury lies in precision, honesty, and pride in workmanship. No shortcuts. No compromises. Just exceptional homes.
Get in touch
Onyx Construct Limited
Rating: 5 out of 5
Extension Builder in Harrow
We are a multi-trade construction company operated in domestic sector and we are able to full-fill any building requirement. The scope of projects we have delivered in the past spans from smallest jobs like kitchen or bathroom fitting to extensions, house refurbishments or loft conversions.The majority of our previous clients were extremely satisfied with high standard and quality of work. If you are looking for professionals builders with reasonable prices - you are on the right profile !
Get in touch
Latest review:
Extensions- 29 Nov 2023
We had the most fantastic experience with Sarunas. He was highly professional from start to finish and completed the work to the highest standard. We extended our project significantly once we realised how excellent he was and he has now renovated our whole home over an 18 month period. He was able to guide us through the process and help us make key decisions which made the experience smooth and efficient. He is extremely skilled in all aspects of building, has high attention to detail and is a pleasure to have in your home! I couldn't recommend him higher and look forward to having him back in future to convert our loft!
IGL Services Limited
No reviews yet
Extension Builder in Harrow
I am a builder with over 10 years of experience in the construction industry, specialising in loft conversions, house extensions and carpentry. Together with my skilled team, we deliver projects across London with a focus on quality, reliability and completing on time. We have successfully completed lofts, extensions and full refurbishments, helping homeowners transform their properties. Based in Greenford, we cover Greater London and surrounding areas. If you are looking for a reliable and experienced builder for both large and small projects, I would be happy to discuss your plans.
Get in touch
Leonard goli
Rating: 4.7 out of 5
Extension Builder in Harrow
Highty skilled construction with 10 years experience. Expertise in planning construction projects,defining scopes of work and labord costs. With plenty of experience in all aspencts of loft convention extensions barhrooms,kitchens,tiles,floor etc
Get in touch
Latest review:
Decking- 1 Jun 2026
Extremely helpful and professional. Thank you
Doherty Builders (Tedd) Limited
Rating: 5 out of 5
Extension Builder in Harrow
An honest good quality, reasonably priced family builders. Over 30 years experience. We take pride in working to a high standard and get great satisfaction knowing clients are happy with our work, many return to us. Once starting we never leave until the job is finished
Get in touch
Latest review:
Extensions- 30 Jan 2022
Christian was great to work with - communicated clearly at every step of the project, was flexible with plans as they changed a bit during the build, and completed the work on time. He managed the sub-contractors (electrician) which made it very easy for us. Highly recommend him!

3.7

Top rated Extension Builders

Our Extension Builders in Harrow, 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 Harrow?

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

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

What are the hourly rates of extension builders in Harrow?

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

Find extension builders in Harrow with MyBuilder

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

Step 2: Compare different extension builders in Harrow

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

Step 3: Hire Harrow extension builders with confidence

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

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

What to ask a Harrow extension builder before hiring?

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

An extension builder in Harrow 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 Harrow 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 Harrow?

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 Harrow 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 Harrow 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 Harrow

Can an extension builder in Harrow help with planning permission?

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

Many Harrow 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 Harrow help with materials and finishes?

Yes, most extension builders in Harrow 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.