In networked control systems the controller of a physicallydistributed plant is implemented as a collection of tightlyinteracting, concurrent processes running on a distributed execution platform. The execution platform consists of a set of heterogeneous components (sensors, actuators, and controllers) that interact through a hierarchical communication network. We propose a methodology and a framework for design exploration and automatic synthesis of the communication network. We present how our approach can be applied to the design of control systems for intelligent buildings. The input specification of the control system includes (i) the constraints on the location of its components, which are imposed by the plant, (ii) the communication requirements among the components, and (iii) an estimation of the real-time constraints for the correct behavior of the algorithms implementing the control law. The output produces an implementation of the control networks that is obtained by combining elements from a pre-defined library of communication links, protocols, interfaces, and switches. The implementation is optimal in the sense that it satisfies the given specification while minimizing an objective function that captures the overall cost of the network implementation.