Ducting Systems and Air Ventilation - any thoughts on the new duct sealing process?

I've been reading about a company that came up with a coating that is applied to your existing under slab ductwork to seal it and repair rust and corrosion issues. They camera inspect your ducts and then spray this coating, and you're good to go in a matter of hours. Does anyone know if this actually works, and is a good alternative to having new ductwork run in the attic? Thanks!

Nobody responded to my question about a company offering a new procedure that seals the inside of your ductwork with a patented material to restore it to good health. I can't seem to find anything on it other than the patent info, the web site of the patent holder, and one company out West that provides the service. Anyone on the boards have any info, either good or bad. On the one hand, it sounds like a logical and possibly good product. On the other hand, too good to be true?

We spray coating in duct system all the time and they work great. The problem you have with under ground duct is access. Even with are robots that we have getting a coating to them will be almost imposable. Under ground duct that has water problems is best to be abandoned filled with concrete and have new duct installed over head.

Thanks for the reply, airman! My place is only around 1000 sf, so I'm thinking it shouldn't be too difficult to get the sprayer where it needs to go. There are only 8 registers in the whole place. My bigger concern is that the ducts may be too corroded for the spray to work (just a guess at this point). I guess the only way to find out is with a video inspection. In your opinion, is the cost of a new furnace and new overhead ductwork ridiculously more than spraying the existing ducts?

Hard to say because I have never seen a coating for sealing underground duct. Let me ask you this How much is your health worth if the coating did not work and you have all the standing water? Mold, Bacteria ?????????????? Like I said before 100% effective is to get rid of the under ground.

Can't argue the logic there, my friend. Thanks!