The process of generating optimized schedules for construction projects is a very time-consuming. For each construction task several execution restrictions, conditions and requirements such as technological dependencies or resource availabilities have to be considered. This leads to a multitude of possible execution orders and consequently to a hard optimization problem. Within this paper the integration of a flexible Simulated Annealing metaheuristic into a constraint-based simulation concept is presented to determine optimized construction schedules. Simulated Annealing approximates the optimized solution by defined temperatures and cooling rates. Both parameters help to define the search process and respectively help to escape from local minima. In the following the Simulated Annealing approach and its implementation are described in detail. Furthermore, the application of Simulated Annealing is demonstrated using an example from construction scheduling.