The products are made by soaking the base in bituminous or thermo plasticity elastomer(such an styrene butadiene styrenef¼SBS),or thermoplastics(such as atactic Polypropylene---APP,APAO,APL)modified bitumenous, then covering double faces with elastomer(SBS)or thermoplastics(APP,APAO,APL)modified bitumenous, and last finishing the upward face with fine sands, mineral slates(or grains)or polythene membrane while downward face with fine sands or polythene membrane. good self heating, easy application, and long service, etc.
