This paper addresses maintenance planning in heritage buildings. Currently, social, economic, and environmental factors raise concerns about the durability and service life of buildings. This study on the service life of historical buildings in terms of functionality presents a complex analysis that has yet to be developed in great depth. In this sense, a new expert system based on fuzzy logic for the prognosis of the functional service life of buildings is established. The system developed intends to manage vulnerabilities and risk variables that affect a building’s performance. These parameters are involved in the building management and maintenance process and indicate durability in terms of serviceability as an output model parameter. The aim of this paper is to describe a new application of a fuzzy inference system based on expert knowledge. This approach discusses the serviceability of architectural heritage buildings using a Mamdani fuzzy model. In this methodology, the vulnerability and risk condition of nine theoretical case studies and five real buildings located in southern Spain are analyzed. In this case study, the application model is shown in a set of a five heritage buildings situated in southern Europe (Andalusia, Spain), which were only analyzed through in situ visual inspections. This system is able to give priorities relating to preventive conservation activities in homogeneous groups of heritage buildings. The approach gives useful information based on a functional criterion regarding the current state of the buildings. The fuzzy model aims to be an indicator for the future evolution of a building’s functionality.

The development of objective methodologies for the preventive conservation of historic buildings is extremely relevant to mitigate the deterioration of buildings and sites with exceptional cultural value. In this sense, there is a growing need to develop comprehensive, coherent plans to manage, preserve and protect heritage buildings in areas that are extremely susceptible to natural disasters, such as the case of the Pacific coast of South America. Two methodologies are presented in this study to assess the functional service life and protection level of cultural heritage in Chile. This research intends to establish a correlation between the functional performance of heritage buildings and the Chilean code related to the definition of the preservation of historic heritage buildings. This study applies both methodologies to 25 heritage buildings (timber housing) located in the city of Valdivia, Chile. A multiple linear regression analysis is applied in order to rank the influence of the variables used to define the protection level, according to the Chilean standard, in the functionality index of timber heritage constructions. The information obtained in this study is exceptionally relevant for the researchers and stakeholders responsible for the definition and implementation of maintenance programmes in building stocks.