The project involved the rehabilitation of around 3,500 m² of tunnel wall surfaces in the Wihalden Tunnel in Kirchberg, Canton of St. Gallen. The aim was to replace the existing coating in order to ensure long-term surface protection and maintain visibility conditions as well as the operational safety of the tunnel.

Nighttime rehabilitation within a narrow time window

The coating work was carried out within a tight schedule from 6 to 13 October 2025, each night from 7:30 p.m. to 5:00 a.m. During this period, the tunnel was completely closed to general road traffic. The work was performed by the experienced specialist contractor Hydrojet AG. The client was the Civil Engineering Office of St. Gallen.

In addition to the regular tunnel wall surfaces, safety-relevant areas were highlighted in colour: emergency exits were coated in RAL 6029 (mint green), while the SOS niches were finished in RAL 2004 (pure orange).

Safe execution under autumn weather conditions

The greatest challenge was the time of year. The work was carried out under autumn conditions, with low nighttime temperatures between 3 and 7 °C and high humidity. These boundary conditions are particularly demanding for tunnel coating work, as they can affect both the application and curing of the materials. Added to this was the high time pressure caused by the narrow nighttime working window: every step had to be carried out precisely in order to keep the project on schedule without delays.

The Civil Engineering Office of St. Gallen had already defined a clear system specification in the tender documents. Based on very positive experience from previous projects, particularly under comparable climatic conditions, MC-DUR 2496 CTP was selected. The responsible project manager was familiar with the product from earlier works and considered it ideally suited to the expected weather conditions.