Design activity is pervasive as it is increasingly expanding into all sectors and every day it is increasingly difficult to anticipate the often unpredictable changes resulting from new inventions and changes in technology, tools, methods and social customs using current design systems, and at the same time we need to preserve and store knowledge and experiences that can help facing aforementioned problems. The present paper illustrates an innovative Rule Layer overlying existing commercial software in order to model Reasoning and Performance verification Rules to be applied to design instances. The authors developed two different prototypes, one on BIM and one on CAD commercial software in order to validate the proposed approach. Results demonstrate the general system potentials opened up to further research development and deepening.