We propose in this paper an iterative method composed of three steps to derive architecture alternatives from quality requirements using a catalogue of patterns and styles. The solution candidates are chosen by answering a set of questions which reflects the requirements. We instantiate then the solution candidates using a UML- based enhancement of the problem frame approach. To ensure that the instantiated architectures fulfill the quality requirements, we evaluate them in the next step. A desired refinement of the software architectures is then achieved by iterating over the described steps.