Newbie Question, Mastic Or Aluminum Tape For Leaks? - HVAC - DIY Chatroom Home Improvement Forum

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Old 01-25-2016, 12:44 PM   #1
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Newbie Question, Mastic or Aluminum Tape for leaks?

I'm sure this question has been hashed out before.
I am noticing some leaks within my HVAC duct system in my attic.

My inspection report noticed a plenum leak as well.

I would like to seal some of this up.

In your opinion, does the alum tape or mastic work better?

Also, what's the best kind to get?
I've heard that Home Depot and Lowe's sells not so good stuff.



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Old 01-25-2016, 05:48 PM   #2
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Mastic is best.


When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
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Old 01-25-2016, 06:37 PM   #3
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If they're small simple leaks then I would go with tape (faster and cleaner). If it's a mess of leaks then the mastic would be better.
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Old 01-25-2016, 06:54 PM   #4
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Ayuh,.... 'n that's what I always thought Duct tape was for,.....
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Old 01-25-2016, 09:24 PM   #5
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Use both, whichever is most convenient. If you are working blind in spots you have to use the aluminum tape, like if you are sealing a 10" pipe already tight up in a joist bay. Junctions where pipe runs into plenum boxes are best done with mastic.

HD/Lowes sells two qualities of aluminum tape, the small paper-thin crap and the thicker good stuff with code writing on it.
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Old 01-25-2016, 09:38 PM   #6
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For us, it depends on what was written on the drawings. Sometimes we have to use tape, then duct sealant over it. (like mastic but dries rock hard in no time, with minimal smell)

99% of our ductwork is in conditioned space. Therefore we generally don't worry about it unless the engineer demands it.



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