The possibility of increasing the durability of coatings based on lime dry construction mix by introducing an additive containing synthetic aluminosilicates is substantiated. The regularities of the structure formation of the lime composite in the presence of an additive containing synthetic aluminosilicates, which additionally consists of a formation of calcium–sodium hydrosilicates and minerals of the zeolite group, an increase in the amount of chemically bound lime by 8.74%, are revealed. X-ray diffraction analysis and thermodynamic calculations have established that the mineralogical composition of the crystalline phase of the additive based on synthetic aluminosilicates is represented by thenardite, gibbsite, and the minerals of the zeolite group. It is shown that the content of the amorphous phase is 77.5%. It was found that the additive based on synthetic aluminosilicates is characterized by high activity, which is more than 350 mg/g. It was also found that the introduction of an additive based on synthetic aluminosilicates into the formulation of a lime dry mixture accelerates the curing of coatings and increases the compressive strength after 28 days of air-dry hardening by 1.9 times.