I need to remove a 2-foot section of ductwork that got flooded so that I can rip out the internal insulation, but I don't see an easy way to remove the drive cleat since there is only about a 3/4" of clearance, and the cleat foldover looks like about a 1.5" from what I can see. I can probably remove some of the drain pipes that is in the way but it would be a major task to remove the boiler that's already been set up with gas pipes and whatnot. This means that the cleat is crowded on both sides with a brick wall on one side and a furnace on the other side blocking the slip off.

Is there a way to pull the drive cleat off perpendicular to the duct with some prying, and get it back on with a lot of hammering, or is it a lost cause?

My plan B if I can't get this off is to cut an access hole and then use a duct insulation sealant like IAQ 8000 to seal the whole thing, but it seems like a pretty expensive sealant and would require spray equipment and some expertise.

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That's tight spot but you have good working space.

Maybe cut & pry off and replace with a handcrafted duct flange of two angle bars ("L" profile) screwed to the duct and then bolted to each other.

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Or hook new cleats on one side only and screw on to other? Since you have internal insulation there is plenty of margin for a screw head to pierce through.

Or cut an access hole and cover with new (larger) sheet. Would you consider replacing the internal insulation where damaged but replace with an external wrap at the new cover over the access hole?

Image https://www.rona.ca/en/angle-bar-solid-steel-3-4-x-4-x-1-8-black-13997775 and https://www.victordist.com/buy/product/Ductmate-Industries-D2510GA/2145

  • I’d be fine not replacing the internal insulation at all so could just leave it uninsulated after. If I did the access hole, should I do a rectangular or round cut? Do you think it’s easier to replace the duct or do the access hole and coating? Sep 18 '21 at 18:20
  • What is a T strip... is there a picture of it somewhere that I can look at to visualize? Sep 19 '21 at 1:48
  • @MonkeyBonkey sorry, wrong word. Edited. I meant an L-profile. Won't be easy because you have to get some sort of access all around, but it's perhaps something to consider. You could cleat the obstructed seams, flange the exposed ones, and seal off the corners with mastic duct sealant.
    – P2000
    Sep 19 '21 at 2:21
  • @MonkeyBonkey as for your cut question, cutting rectangular is easiest. Access holes are easier than complete replacement. So from my view it seems best to: 1. access hole, 2. remove insul. 3. cover with sheet metal (piece of HVAC stack&trunk or unrolled duct pipe is fine), attach with screws, seal with tape or mastic 4. optionally insulate on outside. Best to to tape off edge of exposed insulation on inside.
    – P2000
    Sep 19 '21 at 15:09

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