Televised some underground duct work for a customer that was getting a lot of dust/dirt in the house coming up from the duct work. The metal duct work was heavily rusted out, some areas there was no pipe left at all! We were able to clean all the ducts, apply our spin cast mortar to restructure and even create a new pipe where the old pipe was completely rotted away. After creating a new solid pipe to work with we were able to seal the ducts with our duct armor product leaving a clean air flow.