About us
Greentherm Developments Ltd is a well established South Yorkshire Building Company providing a full range of building and installation services.
Our company has extensive experience in the building industry and employ highly qualified staff.  Much of our work is gained through recommendations as we provide an excellent quality of service and workmanship whilst maintaining a fair price. 
Greentherm provide full project management to deliver projects that are completed on time, in a safe environment, within authorised budgets and to required quality standards. 
Our friendly and reliable staff are here to ensure you receive the best possible service from start to finish. 
We can take care of architectural plans by assisting in obtaining the necessarfy documents and permits.
Works Undertaken
Extensions and Roofing.
New Builds.
Loft and Basement Conversions.
Renovations/ Refurbishments.  
Facility Installations, Bathrooms/ Kitchens.
General Building Works.
Why choose us?
Free, no obligation quote, estimate and advice to all our customers.
Full building control approval and permits.
Professional service, speedy build and high standards.
Single point of contact and management.
All works are insured and guaranteed.

Trades offered

Commercial builder
Agricultural/Farm Building
Builder general
Basement/Cellar conversions
General extension
Loft conversions
Bathroom fitter
Carpenter and Joiner
General carpentry
Roofing general
House Builder
New build
Central Heating
Central Heating
General plumbing

Case studies

Kitching and Dining area

  • 02 Jan 2021
  • Sheffield

Rear extension and re-roof

  • 04 May 2018

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Customer testimonials

09 May 2018

We've employed Greentherm Developments Ltd to do two major renovation projects on our home: a hip-to-gable loft conversion plus a cellar conversion. Although we were nervous about the disruptive impact such major projects could have on our home and family life, we couldn't have been in safer hands. Dave and his team were fantastic about doing the job and keeping disruption to a minimum; Greentherm have an impeccable, perfectionist's eye for detail and insist on the very highest standards of customer care. Dave would debrief me on developments on the job each and every day; he always saw potential issues on the build before they turned into problems. We couldn't be happier with the work they've done for us and wouldn't hesitate to recommend them to potential customers. - MN


02 May 2018

We were introduced to David and his company, Greentherm Developments through a friend who had previously enlisted their services and they came highly recommended. In the last two months Greentherm converted our garage into a utility room and a shower room, which were both delivered to the highest of standards. David and his team have proven to be a trustworthy company with excellent work ethics. Throughout the project, David was very considerate and always ensured we were given the space and convenience that we required. He was also helpful in giving advice and suggestions, even when it was outside the scope of our original agreement. As a team they were polite, friendly and respectful. Importantly they always kept the work area neat and clean at the end of the day. David was also thoughtful in managing the work such that it did not affect our neighbours. In conclusion David and his team have proven themselves to be excellent builders and with his Knowledge and management skills, I would definitely use their services again and would highly recommend them for their efforts. - Dr Tee


30 Apr 2018

I recently engaged David and his team to fit a new kitchen, with new appliances, flooring etc. This was the second time I had asked David to carry out work, previously it had been a bathroom at my last property, I was highly satisfied with his workmanship and the clean efficient way he and his team carried out the work, I never had to call him back as all worked well for the rest of the time we lived there. I had no hesitation in asking him to complete the kitchen at our new home. They carried out the task to our full satisfaction showing flexibility, good problem solving and alternative ideas to suit our needs. His team were trustworthy, polite, respectful and always cleaned up . In due course I shall be asking him to carry out other projects. - Peter


30 Apr 2018

I would like to thank David Mah, Greentherm Developments Ltd for my amazing loft conversion. Every space possible has been converted to superb living space, an incredible en-suite and lots of efficient storage, all at an extremely high standard. His ideas were brilliant and I was given regular updates of progress with any new-found problems being discussed, costed and put right when agreed. His work was top class, his team were quality and they completed on time with no mess left. I am so pleased we were recommended Greentherm Developments Ltd for my loft conversion and will definitely ask him back to do our kitchen. I have no hesitation to recommend Greentherm Developments Ltd to others so they can experience a truly beautiful build’ - M-A


30 Apr 2018

Greentherm Developments have carried out our most recent project on our residential property, which comprised of multiple extensions, full re-roof and numerous installations. I have found their approach both dynamic and innovative, always ready to help with new ideas and a hands-on philosophy. They provide continuous updates with a focus on customer service ensuring dialogue exists at all times. During the project Greentherm Developments endeavoured from day one to get the job finished, this was extremely important when dealing with our deadlines and our expectations. The quality of the workmanship is of a very high standard and it is clear to see they only use the very best tradesman. I have no hesitation in recommending Greentherm Developments and will continue to use their wide ranging services - Mr B


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