The renovation of a significant segment of housing sector in Budapest, Hungary is overdue. Besides other causes, the absence of any effective tool that may support the decisions of the ownership communities in determining the technically verified steps and solutions in repair processes hinders the improvement of the physical condition of old residential houses. In this paper we propose a new formal method and approach for generating such tool that considers the costs and feasibilities of alternative renovation processes with professional data obtained from building diagnostics surveys, technical reports and contractors’ billing database. As a case study, a comprehensive renovation chain of the roof structure of a pre-war residential house will be evaluated.