KÖSTER Polysil TG 500 and the KÖSTER NB 4000 (by spraying) were applied as a positive side waterproofing after the masonry was excavated. Before that, the KÖSTER Repair Mortar NC was taken to level out irregularities of the substrate. Additionally a post-installed horizontal barrier was considered with the KÖSTER Injection Gel G4. Finally, in order to protect the applied waterproofing layer from mechanical damages, especially during backfilling, the KÖSTER SD Protection and Drainage Sheet 3-250 was used.