According to the city, various factors led to the delay of several weeks. First, so-called polycyclic aromatic hydrocarbons (PAH) were detected in exposed old sealing membranes. The material, often referred to as "tar", was used in road construction until the 1970s, but has since been banned because it is considered carcinogenic, explains the Bonn press office. "Since the handling of PAHs is subject to strict rules, a specialised company had to plan and supervise the further procedure. As a result, the construction site was shut down for a fortnight," the statement reads.

In addition, the construction company was affected by Corona, it said. According to the city, the entire construction crew was infected with the Corona virus. This had led to a construction standstill of one week. "Then during the removal of a ceiling section, the brick centre wall below the ceiling section was destroyed and two old chimneys were found that were not shown on the plans. The chimneys have to be backfilled and the wall rebuilt," the municipality further explains.

In addition, a load distribution beam has to be concreted on top of the wall, for which the statics have to be calculated beforehand. Before the concrete can be poured, however, reinforcing steel has to be ordered, delivered and installed. The bottom line is that all this will lead to a delay of another four weeks.

(Original text: ga; Translation: Mareike Graepel)