Televised ducts under slab floor. Ducts are pvc ducts with metal fittings. Metal fittings and plenum are extremely rusted. There was no standing g water in the ducts at the time of the inspection but the house does have a higher than normal humidity level. It is suggested that all downspouts around the building be extended away to help reduce the amount of ground water that may be raising up into the ducts. After the water issue is resolved the ducts should be spin cast mortared on the connections to restore the structure then the entire system spray lined with Duct Armor duct lining material.