The limestone used in the construction of much of the 8-1 ith century Maya structures at Xunantunich, Belize is mechanically weak. Active microfloral growth, cyclic changes in humidity and temperature, and exposure to the erosive effects of wind and rain have resulted in deterioration of the stone used at the site. Limestone samples were consolidated using water-compatible and other consolidants and were exposed to both sunny and shaded tropical environments for one year. Data-logging meteorological stations were used to monitor the temperature, relative humidity, rainfall, wind conditions and solar irradiance during the exposures. Accelerated aging tests on similarly treated specimens were performed in the laboratory. Dilute epoxy and acrylic resin systems in hydrophilic solvents were found to penetrate and consolidate weak limestone. Several biocides applied in dilute aqueous solution were effective in preventing microfloral growth on new limestone and for controlling in situ growth on historic limestone.