LAUSR

ABSTRACT The church of San Diego de Alcalá, located in Pitiquito, Sonora , in Mexico, lies on a missionary road founded by the Jesuit Eusebio F. Kino, which, with the expulsion of the Jesuit order in 1767, passed into the care of the Franciscans. It contains wallpaintings which presented deterioration problems whose cause was not easy to determine, since the damage appeared to be inconsistent with the techniques used and the environmental conditions. With an interdisciplinary team, a methodology was designed for a combined study of the environment of the church and its wallpaintings. Thermal imaging of the exterior and interior walls indicated that the building was made up of different materials, and the junctions between them explained the different deterioration pathologies between one zone and another. Hydrological maps for groundwater in the locality were studied, to elucidate the presence of water in a desert zone; abundant sources of water in the subsoil were identified, which, because of overexploitation of the land, have been diminishing over time. This allowed the elaboration of a plan for site management, through the identification of those deterioration factors that can be mitigated by simple maintenance actions that are inherent to the environment and the materials, which enabled a scheduled maintenance scheme to be implemented. This improved the condition of the building and its wallpaintings, while reducing the resource invested to achieve this goal.