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Diagnosis is the first and most crucial step in the process of monument protection. Diagnosis demands a variety of information and can be a complicated procedure especially when dealing with historical buildings and the limitations that these induce; nevertheless when the correct methodology is followed, diagnosis can be carried out whilst minimizing the amount of samples needed, as important features are already revealed and representative samples can be located. This is achieved through a thorough and organized survey of the historical building and the implementation of various non-destructive techniques (NDTs). The in-situ optical inspection of a historical building can offer valuable information regarding the preservation state of the building as well as utility problems which might create problems for the masonry, such as humidity problems due to the movement of rainwater. Following the optical inspection, the researchers can apply NDTs on the structure as a whole, focusing however on problematic areas or areas of interest. In this study NDTs were employed in order to investigate the type of masonry structure followed by the original masonry workers, the original building materials, the different construction phases and materials, as well as non-documented conservation interventions. However, the use of one NDT alone cannot offer the required information; a combination of various NDTs is necessary in order to extract meaningful and useful results. In the case of Kaisariani monastery, presented here, after a thorough in-situ optical inspection, a variety of NDTs were applied: Ground-penetrating Radar (GRP), Infrared Thermography (IR), Fiber Optics Microscopy (FOM) and Schmidt rebound hammer. The results were analyzed and combined in order to extract results regarding the original building materials, the type of masonry construction, the preservation state of the building materials, as well as information regarding non-documented different construction phases and conservation interventions.

Four different organic systems, containing either vinyl acetate resins or epoxy resins were applied on steel pretreated specimens exposed to deionized and deaerated water taken from the installations of the Public Greek Electricity Company. Electrochemical Impedance Spectroscopy, potentiodynamic polarization measurements, dielectric measurements and visual observations after salt spray test were performed for monitoring the changes of the organic systems characteristics at predetermined exposure time in the deionized – deaerated water. All four coating systems found providing protection on steel surfaces. The classification of their performance depends mainly on the composition of the primer, as well as, on the intrinsic characteristics of the other layers. Thus the system consisting of epoxy primer with zinc dust, epoxy high build layer and a two component epoxy paint with iron oxide is the one exhibiting the highest protection efficiency.

Abstract. Monuments and historical buildings are degraded as time passes due to natural