Architectural design and design decisions are the key components of architectural knowledge. However, concerns, rationales, and risks should be also captured to prevent knowledge vaporization. So, how to deal with architectural knowledge in incremental knowledge refinement? We believe that usage of the knowledge repository system can support architecture evolution. In this paper, a model of knowledge repository is presented. In this model, the decision-centric approach is complemented with the architectural views to support indirect interrelations between design decisions. Support for agile development was one of the key aspects of the model design, therefore knowledge vaporisation might be reduced.