Alpol AF 645 highly flexible acrylic paint is intended for capillary and shrinkage cracks of 1.2 mm in width, also on concrete surfaces. However, if the cracks are structurally conditioned (result from motions of the structure) and, more significantly, they are unstable (i.e. their number and width change in time), coating them will be ineffective, and what is worse, can be dangerous as the actual cause of cracking remains concealed. Whether the paint can be applied for masking structural cracks is to be determined by an expert.