Powerhouse also called a generator house is a place or space that is used to meet the operational needs of buildings, usually used as an installation space for electricity, water, air conditioning, and others. There are many cases of structural damage caused by human error or natural behavior. Structural damage can occur in the construction process or factors of the building itself or external factors. The shape and level of structural damage can occur from mild to severe. In choosing the method for repairing and strengthening concrete structures, several factors must be considered, namely the capacity of the structure, the environment in which the structure is located, the available equipment, the ability of the implementing staff and the limitations of the owner such as limited workspace, ease of implementation, implementation time and cost. Analytical Hierarchy Process is a support systems method in decision making, with real data and carefully studied can solve various multi-criteria decision-making problems, and can solve the problem of choosing the method of repair and reinforcement of concrete in the powerhouse building. The results of the decision making on the repair of concrete building structures can be decided to choose the alternative application of the Mortar Cement as the main choice with the highest value: 0.3485, as the best choice. Furthermore, to strengthen the concrete building structure, it was decided to choose the highest value: 0.3564, with the alternative application of Self Compacting Concrete as the main choice.