Growth of salt crystals within the pores of stone can cause serious damage. Salt may enter with ground water or be created by reaction of the minerals in the stone with atmospheric pollutants. As water evaporates from the pores of the stone, the salt concentration rises and the crystals grow until they approach the pore walls. If the salt came into direct contact with the stone, then growth would stop and there would be no stress. However, in most cases there is a repulsive force between the salt and mineral surfaces, so that they do not touch; instead, the salt remains surrounded by film of solution that encourages it to grow and exert pressure on the pore walls. The goal of this study was to develop a chemical treatment for limestone that would eliminate the repulsion, and thereby prevent salt from applying pressure on the pore walls. On the basis of screening tests, the polymer chosen for testing was polyacrylic acid with low molecular weight (~5000). Potassium hydroxide is used to raise the pH of the polymer solution to 7-8, and the solution is equilibrated with calcium carbonate before being introduced into the stone, where the polymer adsorbs on the pore walls. When crystals of sodium sulfate are induced to grow within the stone, the damage is strongly reduced by the coating in most cases. To date, there are problems of reproducibility with the treatment that are not fully understood. Possible explanations are discussed and additional research directions are proposed.