The objective of this work is to study the effect of synthetic polysaccharides on the structure formation and properties of lime coatings. Information on the effect of synthetic polysaccharides on the structure formation of lime coatings is presented. Additives of water-soluble modified polysaccharides Atren Cem HV and Atren Cem LV are considered. It is shown that due to the water-retaining effect of the additive, more favorable conditions are created for lime carbonation. It is shown that due to the adsorption of polysaccharides on the surface of lime particles Ca(OH)2, the rate of growth of the particle size of portlandite crystals slows down. The amount of calcite in the control samples is 87.4%, and in the samples prepared with the additive – 88.87%. Using X-ray phase and thermographic analysis, optical spectroscopy, the presence of inter- and intracrystalline organic compounds was established. It was found that a slight increase in the width of the CaCO3 peaks is observed in the diffraction patterns, which indicates the possible inclusion of organic molecules in calcite, which modify the (nano)structure of newly formed calcite crystals and increase the strength of lime coatings. The formation of a lime composite structure with inter- and intracrystalline organic molecules imparts higher deformation properties to the lime coating, helps reduce the modulus of elasticity and hardness of the coatings, which ensures higher crack resistance of the coatings during operation. Lime coatings containing the Atren Cem LV additive in the formulation withstood 35 cycles of alternating freezing and thawing.