Grey and beige Polymer Sand is a unique blend of polymer binders and calibrated sand. When Polymer Sand comes into contact with water it becomes very solid and blocks the grout between the blocks, while maintaining the floor set in place. It helps prevent weed growth, damage caused by insects and erosion caused by rain. If applied on concrete surfaces, use only Non-Draining Polymer Sand. You should not use it on mega products (Via Veneto Series).