Full Renewal of the Wihalden Tunnel‘s Coating
The Wihalden Road Tunnel in the Swiss canton of St. Gallen is a key part of the regional transport infrastructure. In October 2025, the existing tunnel coating was completely renewed as part of a compact night-time repair project.
This project, commissioned by the St. Gallen Civil Engineering Office, involved the refurbishment of approximately 3500 m² of tunnel wall surface. The aim was to replace the existing coating to ensure long-term surface protection and good visibility within the tunnel.
Night-Time Refurbishment Within
a Tight Timeframe
The coating work was carried out within a tight timeframe of just one week, with work from 7.30 pm to 5.00 am each night. During these hours, the tunnel was completely closed to general road traffic. The work was carried out by the experienced specialist contractor Hydrojet AG, who applied the MC-DUR 2496 CTP tunnel coating from MC-Bauchemie.
In addition to the light-coloured coating applied to the standard tunnel wall surfaces, safety-critical areas were highlighted in colour: emergency exits were coated in RAL colour 6029 (mint green), whilst the SOS niches were finished in RAL colour 2004 (pure orange).
Safe Implementation in Autumnal
Weather Conditions
The work took place in autumnal conditions – with low night-time temperatures of between 3 and 7 °C and high humidity. These conditions present a considerable challenge for coating work in tunnels, as they can affect both the workability and the curing of the materials. Added to this was the significant time pressure caused by the narrow night-time working window: Every step of the process had to be carried out with precision to ensure the construction schedule could be maintained without delays.
The St. Gallen Civil Engineering Office had already defined clear system specifications in the tender. Based on very positive experiences from previous projects – particularly under comparable climatic conditions – the MC-DUR 2496 CTP coating was selected. The project manager in charge was familiar with the product from previous projects and assessed it as ideally suited to the expected weather conditions.
The coating was applied in two layers using an airless spraying method. According to the manufacturer, this tried-and-tested material is characterised by reliable application even at low temperatures and high humidity, as well as by a robust, uniform surface finish. The speed of application and curing were decisive advantages under the given conditions, and the refurbishment of the Wihalden Tunnel with new uniform and durable coating surface was thus completed within the specified timeframe.
