Climbing robots perform maintenance and inspection tasks on vertical structures that are difficult to access, preventing human operators from putting their physical integrity at risk when working in these scenarios. A common scenario where these tasks are performed are metallic truss structures, such as those present in power distribution towers, bridges or skeletons of industrial buildings. In order to move autonomously through such structures, they must be able to plan a trajectory to a specific point on the structure. They must do this while avoiding collisions with the environment and making transitions between the faces of the structure. This paper presents a hierarchical path planning algorithm. The proposed planner is based on the division of the global problem into several sub-levels, each one in charge of a part of the generation of the sequence of adhesion points that will allow the robot to reach the desired point autonomously.