Inspection of under-slab ducts via televised survey revealed concrete ducts with metal fittings showing slight rust. To address this, we recommend a two-step solution: Spin casting of metal fittings: This process will restore and protect the rusted metal components. Spray lining with Duct Armor: After spin casting, we'll apply Duct Armor duct lining material throughout the system. This comprehensive approach will seal leaks, prevent further corrosion, and improve overall HVAC efficiency, extending the lifespan of your under-slab ductwork.