Recently Cortec provided a solution for the restoration of Zagreb Cathedral. Built in 1093, it is the tallest building in Croatia and attracts thousands of tourists worldwide. Since low-quality stone was used in the past due to economic reasons, it soon started to deteriorate, affected by weather and city pollution.
The final reconstruction started in 1990 and has been going on ever since by phases and priorities. During reconstruction work on the south tower, damaged steel bands were detected surrounding the tower approximately every three meters in height. The bands were covered with rust and in drainage areas, visual damage to the diameter of the bands were present.
Faculty of Mechanical Engineering examined the bands and performed experiments on the steel bars. They recommended removal of loose corrosion from the bands’ surfaces, enhancing the bands in the areas of damage and application of Cortec’s anti-corrosion protection product – CorrVerter.
CorrVerter is a water-based primer that converts rust into a protective layer and is capable of penetrating into the depths of corroded surfaces. It contains a novel chemical chelating agent that modifies surface rust into a hydrophobic passive layer. Two-layers of CorrVerter coating were brushed onto smaller surfaces and sprayed in larger areas directly onto the metal bands. The bands were then reinforced with steel fishplates that were welded on the bands and also protected with CorrVerter.