New School Roof Using Sika Sarnafil PVC in Kingsley, MI Written by dewardknapp on March 21, 2019. Posted in Replacement Roof. New PVC Roof Requires Removal of Previous Gravel Roof Special vacuum equipment allows removal of gravel used on the old roof.Heavy duty vacuum removes gravel prior to installation of the new PVC roof.The vacuum hopper drops the removed gravel directly into the dump truck. Previous Next