We are repairing all of the heavily deteriorated underground air ducts with our Trenchless cast mortar process. This process involves spraying a mortar slurry on to the rusted elbows and connections to give them a strong structure. We will then apply two applications of our rubberized duct lining material to all of the underground air ducts. This will completely encapsulate them and sand will no longer blow out of the air vents.