I had to remove the bottom foot of internal duct insulation touching the ground due to sewage backup.

Now that there is a frayed edge of internal insulation inside the ductwork with the remaining insulation continuing above the flood water line. Is there something I can use to prevent loose fiberglass fibers from this border from going into my return airflow?

I saw that there are some insulation edge sealing sprays, but in this case it's not at the end of a duct but in the middle. Can I tape down the edges with a mastic foil tape, or does that not work because it wouldn't stick to the insulation?

What's the easiest way to seal the frayed fiberglass insulation border in the inside of my return duct?

enter image description here enter image description here enter image description here enter image description here

  • Will stick to the insulation, but only to the fibres on the surface, very weak holding power. Can you place the tape on solid surfaces to cover open fibres?
    – crip659
    Sep 14 '21 at 12:14
  • it would only be half I suppose... i.e. 1/2 on the bare metal and 1/2 on the fiber ends Sep 14 '21 at 12:31
  • Your return air filter should be stopping the insulation from making it into your airflow. If a large chunk breaks off then you obviously need to remove it so that it doesn't impede air flow.
    – MonkeyZeus
    Sep 14 '21 at 12:32
  • 1
    Is this a follow-up to diy.stackexchange.com/q/234493/42053? If so, please provide a picture of the frayed insulation. I assume this is just some foil-faced stuff?
    – MonkeyZeus
    Sep 14 '21 at 12:33
  • Just one end of the tape on metal will just pull off the fibre in time, need both ends on metal/solid surface to last.
    – crip659
    Sep 14 '21 at 12:44

I would recommend cold weather foil tape. That stuff sticks to everything. You could also use epoxy resin tape (Tuck Tape) uses on Tyvek on exterior walls. Both stick to just about everything.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.