A significant amount of public funds in Cyprus are allocated for civil infrastructure construction and maintenance. As technology progresses, coupled with the need to increase the general safety of structures and citizens, the civil infrastructure is required to become “smart” by incorporating sensing technologies. An essential parameter to assess the health condition in concrete structures is the internal moisture which is linked with the concrete deterioration mechanisms, such as carbonation, frost, corrosion and crack formation and can be measured indirectly by monitoring the relative humidity (RH). This paper is a review of the latest results regarding the project “ACOReS”. During the research project, we developed a novel monitoring system based on polymer optical fibre sensors embedded in concrete structures. The proposed polymer sensors used to measure essential quantities in concretes, such as relative humidity, temperature and strain for estimating the health condition of the building structures.