Single Storey Extensions
If you’re struggling for space in your South Wales or South West home, adding a single storey extension is definitely the way forward. Moving home causes so much upheaval and is massively costly, while extending your existing home can actually save money over the long term. What’s more, you can tailor your extension so it’s geared exactly towards meeting your needs.

Why choose single storey extensions from Thermotech UPVC Products Ltd?
We’re the experts when it comes to single storey extensions in Wales and the South West, and we’re so proud of our 100% satisfaction record. That’s because we’re a family-run business, and take the time to ensure all team members are fully trained and supported in their roles. What’s more, we only supply the highest quality products, and all our building work is backed by cast-iron guarantees.
More about our single storey extensions
We typically build single storey extensions at the side or back of properties, as this often means there’s no need for complex planning negotiations with councils. However, we’re committed to providing 100% customer satisfaction, so if you’re considering any type of single storey extension to your home, we’ll talk you through all the details.
Single storey extensions can be the best solution for growing families, and are a fantastic way to create links between the home and exterior living spaces. That’s another reason they’re increasingly popular.


And, finally, our single storey extensions maximise the amount of available light in any home. We’ll always incorporate our top quality UPVC doors and windows into extension designs, ensuring you benefit from significant levels of light throughout the day, no matter what the season.
Browse our online gallery to learn more about the high-quality windows, doors, and extensions offered by Thermotech, or give us a call to discuss your requirements in detail. We give 100% to each and every job, and that’s one of the reasons our customers praise us so highly.
Become our next satisfied customer

Expert Fitting
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Family Run
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A Rated Windows
as Standard

10 Year Guarantee of
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Latest reviews
I spent a lot of time researching window companies that were both good value,supplied good quality products and had good reviews for their customer service and fitting. I'm glad to say that from that from the time of placing the order to the completion of the installation of our beautiful new windows everything was done as expected and on time. We were informed when the windows would be fitted and the fitters were there on time . They take great pride in their work and left us with quality windows that make a huge difference to our house. I would not hesitate to Recommend Thermotech products who are a local family business.
michael simms
March 3, 2023Absolutely brilliant from start to end. Very professional, polite and not an issue having any of the builders in your home, nothing is too much trouble and every last job finished to an excellent standard. Would highly recommend.
Karon Edkins
March 3, 2023🌟🌟🌟🌟🌟 Definitely a five star rating Absolutely delighted with the new front door! From the initial ordering process to the final fitting, the customer service was outstanding. The Thermotech team was incredibly helpful making the entire experience smooth and stress-free. The quality of the product exceeded my expectations, with exceptional attention to detail.The fitting was done with great precision, and the installers were professional and efficient. I couldn't be happier with the result. Highly recommend Thermotech to anyone.
Carla Higgins
January 3, 2025Professional service from start to finish. Attention to detail and quality is Brilliant. Love my new front door. Thank you
Shannon Ryder
September 3, 2024They fitted us in quickly to replace some patio doors, and the man who came to fit them was so friendly and knowledgeable. They look fantastic, really smart, we're very happy with them. Will definitely use them again in the future if needed.
Harriet Challoner
October 3, 2024Following a friends recommendation we contacted Karl to get a quote to replace our conservatory polycarbonate roof with glass. He gave excellent advice on the selection of the best grey glass and a good quote for the job, which we accepted. The installation was undertaken by Steve and Andy. They worked hard to complete the job in a day and a half in a tidy and efficient manner. They were polite and considerate all the way through. We now have a new roof which makes the conservatory look modern and up-to-date. It is wonderful to enjoy the conservatory even more than before with a lovely view of the sky, trees and birds. Thanks to Karl, who kept us well advised on the project, and his hard working team, all of whom we can sincerely recommend to do a great job. Looking forward to enjoying what we hope will be a wonderful summer in the comfortable conservatory.
alan Lloyd
March 3, 2023Absolutely superb, nothing was too much trouble; they went above and beyond to give us exactly what we wanted. They gave me the 'boot room' I wanted, storage for shoes, dogs stuff and loads more. Warm, cosy and dry. Would definitely recommend to anybody, we will certainly be using them again. Can't thank Thermotech enough x
Wendy Dix
August 3, 2024Recently had a single storey extension completed by Thermotech. Very professional and helpful throughout the project. Big thanks to Steve for all his hard work. Pleased with the overall finish. Would recommend this company.
Andrea Clements
March 3, 2024Amazing service!! Came out and measured up after a break in into our showroom, made it secure. Then came within Two days and fitted new glass. Even cleaned up all the mess from the break in. Would recommend to anyone
marc potter
March 3, 2024
🌟🌟🌟🌟🌟 Definitely a five star rating Absolutely delighted with the new front door! From the initial ordering process to the final fitting, the customer service was outstanding. The Thermotech team was incredibly helpful making the entire experience smooth and stress-free. The quality of the product exceeded my expectations, with exceptional attention to detail.The fitting was done with great precision, and the installers were professional and efficient. I couldn't be happier with the result. Highly recommend Thermotech to anyone.
Carla Higgins
January 3, 2025They fitted us in quickly to replace some patio doors, and the man who came to fit them was so friendly and knowledgeable. They look fantastic, really smart, we're very happy with them. Will definitely use them again in the future if needed.
Harriet Challoner
October 3, 2024We have used thermotech on two occasions .the service we recieved from ordering to installation was excellent, Carl and Steve went out of their way to ensure a friendly and helpful experience we would highly recommend them to anyone thinking of having work done 5 star company phil&rose thompson
Phil Thompson
October 3, 2024I would highly recommend Thermotech. I am so pleased with my new extension and windows. I found them experienced and professional from start to finish, with a high skill level in all areas.
Lorraine Bright
October 3, 2024Professional service from start to finish. Attention to detail and quality is Brilliant. Love my new front door. Thank you
Shannon Ryder
September 3, 2024Absolutely superb, nothing was too much trouble; they went above and beyond to give us exactly what we wanted. They gave me the 'boot room' I wanted, storage for shoes, dogs stuff and loads more. Warm, cosy and dry. Would definitely recommend to anybody, we will certainly be using them again. Can't thank Thermotech enough x
Wendy Dix
August 3, 2024Thermotech brilliant yet again! Required some house roof advice and Thermotech called straight over. They arrive on time, never let anyone down and are just amazing. Thermotech are so trustworthy, professional and produce work of a very high quality. I wholeheartedly recommend them to everyone! Thank you ever so much Thermotech for always being so wonderful.
rhian
March 3, 2024Amazing service!! Came out and measured up after a break in into our showroom, made it secure. Then came within Two days and fitted new glass. Even cleaned up all the mess from the break in. Would recommend to anyone
marc potter
March 3, 2024Cannot recommend highly enough - excellent. Karl responded to queries straightaway - great customer service, extremely knowledgeable. A fantastic installation experience. Steve is a highly skilled professional fitter with amazing attention to detail and exceptional quality of work. Everything was cleared up and left immaculate afterwards. Nothing is too much trouble. A huge thank-you to both.
Duncan Kew
March 3, 2024Recently had a single storey extension completed by Thermotech. Very professional and helpful throughout the project. Big thanks to Steve for all his hard work. Pleased with the overall finish. Would recommend this company.
Andrea Clements
March 3, 2024
Contact us
It’s easy to contact us via phone, email or this online form.