The WTA certificate is a certification system created by the WTA (Wissenschaftlich-Technische Arbeitsgemeinschaft für Bauwerkserhaltung und Denkmalpflege). WTA is an international scientific and technical working community specializing in the sustainable preservation of buildings and the protection of monuments. The purpose of the WTA certificate is to ensure the quality, reliability and long-term performance of building materials and systems.

In order to obtain the certificate, the products must undergo strict tests and examinations, during which their physical, chemical and mechanical properties are checked. During these tests, special attention is paid to the products' durability, resilience and environmentally friendly properties. WTA-certified building materials meet the highest industry standards and guarantee the safety and durability of buildings.

The use of materials with such certification is particularly important when renovating historic buildings, as these materials contribute to the preservation of the buildings' original condition and long-term sustainability. The WTA certificate thus means a kind of quality assurance for both professionals and customers.