Surface preparation is an important element of the repair process, both with shotcrete and cast-in-place concrete. It covers a large scope, including concrete removal, saturation of the substrate, the use of bonding agents (rare with shotcrete), and cleaning of the surface. These operations are influenced by the local conditions (surface position: vertical or overhead, the presence of reinforcement) and are very important for both the short- and long-term bond strength and, thus, the repair integrity. When all steps involved in surface preparation are considered, it is obvious that these operations represent a large part of the repair cost and may reach up to 50% of the total repair cost. For this reason, it is important not to neglect surface preparation.