Thread: Help Identify duct deterioation

Inspecting a house with 2 split systems. I found this deterioration on one duct but not the other. Please help me identify what it is and what is causing it.

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It looks like 1" ductboard duct. It has a foil face on the outside of the fiberglass board. It may only be that the installer waved his torch across the foil face when he did the A/C line set. I don't think there is any damage to the fiberglass board from what I can see in the picture.

Originally Posted by Rick Hill

It looks like 1" ductboard duct. It has a foil face on the outside of the fiberglass board. It may only be that the installer waved his torch across the foil face when he did the A/C line set. I don't think there is any damage to the fiberglass board from what I can see in the picture.

It is just the foil that seems damaged, but it felt moist. Is there any way that it coul have gotten wet from the inside?

The foil is the air barrier, if the foil is damaged in any way then it needs to be repaired (properly taped over is a suitable repair, and that does not mean just a small piece of foil duct tape stuck over it like a Band-Aid bandage).

With the air barrier torn that badly, there could be condensation in the insulation, or could it be from a leak above?

In the first photograph, which way is "up" as in where is the sky...and which way is down...as in what "faces" the ground.

What's that under the black tape peaking out from the insulation for the refrigerant line?

Looks like a something has leaked on the fiber duct for quite some time causing the deterioration. The stuff under the black tape looks like silver duct tape.

Originally Posted by H.G. Watson, Sr.

In the first photograph, which way is "up" as in where is the sky...and which way is down...as in what "faces" the ground.

What's that under the black tape peaking out from the insulation for the refrigerant line?

For the life of me, I can't figure out why that would ever matter in this instance.

Do you understand what is depicted in the photo?

I can tell you I have seen this lots of times it is caused by what Rick Hill said by a torch. The moisture you feel is from the duct sweating under the insulation. This is just duct wrap that is used to prevent the duct from sweating in unconditions spaces. Your best bet is to have the home owner see a HVAC contractor and pick up a small piece of duct insulation. Have them get enough to cover the area by a couple inches on each side and cover the damaged area. Use duct foil tape to hold new piece in place.