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Community and Q&A

Installing Duct in a Tight Spot

PLIERS | Posted in General Questions on

Hi hope all is well. I have a flexible hvac duct that is crossing over under a joist. On top of it looking terrible, it feels wet to touch in area it looks like has been taped. I’m wondering if I can convert into something that won’t dip down so low and fit better in ceiling ( picture attached). I would rather not cut a hole in joist. Moving it over a joist from start is also complicated.

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  1. Expert Member
    BILL WICHERS | | #1

    The best way to do this is probably a short section of rigid ducting with appropriate bends and transition fittings. Rigid duct pretty much guarantees a cleaner installation compared to flex duct, but rigid duct is a lot less forgiving in terms of alignment and routing. You can get the parts to try this at any of the box stores, along with tin snips and related tools.

    I recommend wearing gloves while doing the sheet metal work. It's easy to get cut, and the cuts can go pretty deep if you're not careful. Stabs are another problem, since you usually end up with some pointy shard-like spots while cutting the metal. You'll want some mastic (best) or foil tape (close second) to seal things.


  2. PLIERS | | #2

    Thanks Bill I’m going to give it a try. I tried to find some information online walking through the process but it actually very hard to find. I’m thinking of cutting the flex duct with a straight cut and then finishing off that spot with round rigid duct. Anyone know that conversion piece I need to go from flex to rigid?

    1. Expert Member
      BILL WICHERS | | #3

      It's a coupler with some straps, basically. Nothing fancy. You can probably find the fittings in the box stores.


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