Similar to standard masonry structures, masonry tunnels built with natural stone or brick can also be injected. The injection material is injected with the designated pressure through a grid of drill holes. The goal is to waterproof the water bearing areas in the building element in order to later apply negative side waterproofing.
Hollow spaces behind masonry components require special attention. Here air-filled joints as well as large voids which are more or less filled with water-saturated material (such as earth, sand, gravel, or rubble) can be found. In many cases, it is important to ensure that no structural bonding with the surrounding rock layers takes place.