Some important problems of building maintenance is cleaning of walls, ceilings, and floors, cleaning of window glasses in high rise office buildings. The problem is specially advanced for application in nuclear power station halls, under ground stations etc. Robotic systems for these purposes consist of mobile robot having horizontal motion with wall climbing robot installed on its body. Each robot is supplied with cleaning instruments. Wall climbing robot has the possibility to be attached and detached with horizontal motion robot at full automatic mode. In addition to that it should be always insured that the climbing robot at its working zone is placed in the most stable posture so that the vacuum created inside the gripper will be minimum to avoid surface damage. In this paper a method has been addressed for finding most stable posture for the robot body for a particular gripping position. Also some results of testing and experimental investigations of the floor and wall cleaning robotic system have been presented.