Twenty years after the transition to the market-based housing sector the overall physical condition of pre-war urban-type residential houses remained below standard in Hungary. Among other factors, the fragmented ownership structure (at present, the capital-scarce former tenants constitute the stakeholders' community), and the given physical condition of the residential houses has resulted in difficulties in maintenance and repair. The options in the renovation process are limited by financial capabilities, however, the essential problem with maintenance originates from the unprofessional approach in decision-making. Although several decision-support tools exist that may help the stakeholders' communities, some properties of these tools make them unsuitable, or, as in the case of the facility management systems, their application may result in oversized expenses with needless functions. As a combination of the fuzzy signature structure and the principles of finite-state machines a new formal method is proposed for generate a tool for the supporting stakeholders' decisions in the building rehabilitation process, concerning necessity, cost efficiency and quality. With the support of information obtained from building diagnostic surveys, technical guides and contractors' billing databases an optimized renovation protocol is proposed.