An allrounder for monument protection
The interior of the 16th century Willibrordi Cathedral in Wesel, Germany, has stood the test of time well. The exterior presents a different image, however: algae and lichens cover parts of the basalt base, and dirt and dust have blackened some of the window ledges. Like the Late Gothic cathedral, many other monuments have the same problem, and the cost of regular cleaning is often too high. But Evonik has developed a suitable active substance that erases the marks of time from old masonry and equips it to face the future.
Waterproof and breathable
TEGO® Phobe is the name of this miracle product. Its advantage is that it repels rainwater without sealing the stone. “The principle's the same as for a Gore-Tex jacket,” says Jürgen Kirchner, an Evonik engineer. Moist masonry is able to dry without fresh moisture penetrating from the outside. TEGO® Phobe is mixed into silicone resin paints or impregnations and can be very easily applied.
Defying dirt
Evonik's long experience in developing silicone resin paints is now being put to good use in monument protection. Various TEGO® Phobe formulations are currently being tested on stone samples. A special soiling machine has been developed specifically for this purpose, in which the samples are flushed with water, tar, and soot. “This allows us a quick simulation of the damage that might be caused over several years,” explains Kirchner. A number of different paints are being used to optimize each formulation.
No chance for algae and lichens
In protecting against moisture and discoloration, TEGO® Phobe deprives algae and lichens of water, which is essential for them to grow. The first parts of the cathedral’s facade will very soon be treated with Evonik formulations containing TEGO® Phobe—a true all-rounder for monument protection.
