If your home is built on a slab rather than over a foundation then the HVAC ducting will be buried underground. Anything that is underground will be exposed to the elements, including moisture. The majority of sir ducts are made from galvanized sheet metal which stand up to moisture will for some time but eventually it will begin to rust. Rust in itself is a problem but as rust indicates the presence of moisture, it is also a place that will harbor harmful mold. As time goes by and the rust continues to eat away at the ducts, they will eventually collapse.
If rust in air ducts reaches the point where the ducts collapse the traditional solution has been to abandon them and convert the system into overhead ducting. Although this is a solution, it is one that is going to cost a great deal of money and take considerable time to complete. Installing an overhead system also makes it harder to heat the home in winter and can reduce the value of the property if not done well.
The new alternative:
Thanks to new technology and materials it is now possible to encapsulate the existing air ducts in a rubber membrane. This material, when applied to duct work solves numerous problems; of course it seals areas that were damaged by rust but the process also seals the ducts from intrusion by dust and debris, eliminates insect and rodent problems and seals the surfaces which eliminate any potential problems with mold.
Once the technicians have run a video camera through the ducting system they will be able to identify the problems and their location. Once the ducts have been cleaned of all dirt, debris, insect casing, rodent droppings etc the interior of the duct is lined with a spray on rubberized material. It is quick and easy to apply and as there are no harmful chemicals in the product, there is no reason to leave your home while the technicians are working. For more information visit Duct Armor.