Updated August 2024
We’re committed to providing some of the longest guarantees in the timber window and door industry. But how can we be sure that a product will last 10 or more years without actually waiting that long? The answer lies in accelerated testing methods, such as QUV testing.
QUV (or Q-UV) testing is a laboratory process that simulates the effects of long-term weather exposure in a condensed time frame. By placing coated timber samples in a controlled environment that cycles through UV light, heat, and moisture, we can replicate years of weathering in just a few months.
For our products, we worked with a new supplier based in Venice, Italy, beginning in 2013. While we were already confident in the general durability of water-based paints over 12 years of real-world use, we needed to be sure that the updated system would live up to its claims.
Over just four months of QUV exposure, our painted timber samples went through conditions equivalent to 10 years of UK weather. Because the testing was conducted in Italy, where UV exposure is more intense, we believe this test realistically equates to 12–15 years of regular UK service.
The samples were finished using our agreed paint specification and process, then sent through the test cycle. When assessed under the correct lighting, only minor erosion and sheen loss were visible where coatings had been intentionally exposed. In practical terms, this confirms that the coating maintains its protection well beyond our 10-year guarantee.
The British Woodworking Federation (BWF) conducted an 18-year live test of timber coatings through its Servowood project. They then ran QUV tests on matching samples and compared the results. The outcome confirmed QUV as a reliable method for predicting long-term coating performance.
The BWF recommends a minimum coating build-up of 140 microns. In contrast, Gowercroft applies between 210 and 250 microns of paint thickness. This significant increase ensures better protection and longevity for your timber windows and doors.
Thanks to our testing and product development, we can confidently offer a 10-year no-maintenance guarantee on our timber window coatings. This includes our Accoya and engineered Red Grandis products, finished with Sirca water-based microporous paint. After the initial 10 years, future recoating is straightforward and only required every seven years.
If you’re looking for complete peace of mind, we also offer TimbaCare — a unique serviced maintenance programme that extends your warranty indefinitely.
Yes. We’re currently running additional QUV tests specifically for coatings applied to Accoya, with the goal of offering an unprecedented 15-year no-maintenance guarantee. This would represent a new industry benchmark and reinforce Gowercroft’s position at the forefront of timber window technology.
If you have any questions about QUV testing, coating performance, or our guarantees, contact our team. We’d be happy to talk you through the science behind our long-term durability and help you choose the best timber windows and doors for your project.