In this study, fluorinated phosphoric esters are evaluated as protective material for limestone from water-driven alteration processes. Hypotheses as to their molecular arrangement are also provided. The surface composition of limestone after treatment with a commercially available fluorinated phosphoric ester material was evaluated by X-ray photoelectron spectroscopy (XPS). Results were then compared with those obtained for the treated limestone after accelerated aging tests. In the limestone that had not been subjected to the aging processes an XPS determined thickness of the protective coating equivalent to 95±18Å was observed. This fell to 49±10Å in the limestone examined after intensive aging tests. However, low surface wettability ( =135 ±4) was seen to be maintained.