When only the best will do – the story of a Finnish roofing screw.
Kingi was born from the observation that even the best metal roof will not last if its fasteners rust or leak. There was no roofing screw on the market that could genuinely withstand harsh weather conditions while meeting the needs of both builders and customers and regulatory requirements.
We wanted to develop a screw whose corrosion resistance matches the level of the best roofing sheets and whose service life is as long as the roof itself. We took on the task of saving Finnish metal roofs, one screw at a time.
The world’s first three-layer-coated roofing screw
A great innovation was born from a small observation
In the 1990s, Master of Science in Engineering Jorma Kinnunen developed the premium-class Pural® coating for steel roofs. Soon, however, a critical contradiction was noticed: although the roofing material was top quality, the single-layer-painted screws used to fasten it rusted and leaked.
The weakest link in the roof was the fastening.
As a solution, we developed the patented Durabl3 three-layer coating, which gives the screw exceptional protection against mechanical stress and corrosion caused by weather conditions. The difference between ordinary single-layer-painted roofing screws and KINGI® is a class difference, not a difference in nuance.
At the same time, we refined the screw design to perfection. We developed the design-protected CrownD crown head, which directs water away from the screw surface, as well as the FastFX quick tip, which makes installation exceptionally fast and safe. Three innovations, one goal: a screw that lasts as long as the roof itself.
A ten-year battle – the world’s first C4-approved carbon steel screw
When talking did not resolve the market’s shortcoming, we set out to fix it
When we entered the market, we noticed a serious shortcoming in the industry. The old European assessment document (EAD) allowed only roofing screws made of stainless steel for outdoor use. Despite this, painted carbon steel screws have been and still are sold on the market for outdoor use with misleading CE marks and documentation.
At Kingi, we refused to play this game. A carbon steel screw can be just as durable as stainless steel if its coating is made correctly. The problem was not the material, but the fact that the industry standard did not recognise this possibility. We wanted to change the standard, not adapt to inadequate regulations.
We fought for ten years, all the way to the European Commission, to have the industry standards changed to be based on actual corrosion testing – not assumptions.
The work was not easy. Changing a standard requires long-term advocacy, thorough research and the ability to prove claims with independent tests. We subjected our screws to the toughest tests at the HAMK Thin Sheet Centre, obtained Qualisteelcoat approval for the coating material and submitted the results to European standardisation bodies.
The uncompromising work was rewarded. In 2025, a new assessment document (EAD 330046-02-0602) was published, and KINGI® became the world’s first painted carbon steel screw to receive ETA-25/0267 approval for the severe C4 atmospheric corrosivity category.
We did not just meet the standard. We helped change it.
Designed, coated and tested in Finland
A Key Flag product that creates jobs and more sustainable construction
KINGI® roofing screw is a Key Flag product. This means that the product is owned by a Finnish company, a significant part of its added value is generated in Finland, and its degree of domestic content is over 50 per cent.
The screws are coated at Kingi Oy’s own production facility in Nurmijärvi. From foreign suppliers, we procure only those semi-finished products and raw materials that are not available in Finland, and we monitor their quality just as strictly as the quality of our own production, through internal audits.
This is not just a marketing story. It is a practical choice: when the coating process is under our own control, we can ensure the quality of every screw. And when the component chain runs mainly within Finland’s borders, every installed KINGI® supports Finnish work and more sustainable construction.
Would you like to hear more?
Our story continues on every roof where a KINGI® screw is installed. Whether you want to discuss fastener choices for a design project, order a screw sample or simply better understand why KINGI® has been built the way it has, get in touch.