The Cathedral of St. Peter in Schleswig is exposed to harsh climatic conditions and so the west tower has been refurbished. On many days throughout the year, the force of the strong winds causes the rainwater to be pressed against the clay brickwork. The facing brickwork of the outer leaf of the west tower cannot resist this pressure indefinitely. Water ingress via the joints had led to such severe damage that the outer leaf had to be extensively repaired and in some places completely rebuilt. To prevent separation between the mortar of the joints and the brickwork, a pointing mortar with good adhesion was crucial for this refurbishment concept.
The wibbeke denkmalpflege company was appointed to supervise and carry out all the works for making good or replacing the masonry. To find the right pointing mortar, the company prepared a number of sample mortar panels beforehand and had these tested in a laboratory to assess their suitability. A trass-lime pointing mortar specially formulated to suit the existing brickwork and the local conditions proved to be the best choice. The workability properties were also extremely important, because only when the mortar can be applied properly to the side of each joint is a consistently high standard of work possible.