Should the internals of a register where connections are made have gray duct sealant?
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where is the duct sealant in the picture? – jsotola Jul 25 '22 at 01:47
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I’m sorry, I’m asking whether it should have it. There isn’t any in the photo. – Envieddesigns Jul 25 '22 at 02:12
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are you asking about duct tape? – jsotola Jul 25 '22 at 03:30
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Are you asking if code requires it? If so, then you'll have to tell us where you live and when it was built. Are you asking if it's a good idea to apply it? Then please clarify that. In either case, please [edit] the info into your question – FreeMan Jul 25 '22 at 12:12
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Is there duct sealant on other connections in the system? – Steve Wellens Jul 25 '22 at 12:52
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I sure hope that is a return and not a supply. Unless that is some odd square register opening. – Glen Yates Jul 25 '22 at 22:50
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It is a supply register in a bedroom. It’s square shaped. If I have a duct leaking cold air in the attic where it connects to the trunk, I’d like to correct that, is there anywhere I can get specific instruction on doing so. I know there is a nylon zip tie on there do you just snip that off I’m also going to inspect that duct from the inside if I can disconnect it from the trunk. There’s a crap load of foil tape there an still feel air. Not happy with that. – Envieddesigns Jul 26 '22 at 13:01
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@Envieddesigns It sounds like the installers did a $hit job with the flex duct in your attic. Google "connect flex duct to collar" to get started. – MonkeyZeus Jul 26 '22 at 13:58
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When we built in 1994 the sealant on metal duct connections was part of a series of steps to make new construction more energy efficient. This program was promoted by the power company as "best practice" and if you did all the steps, they gave you a cash credit on your bill.
Using duct sealant was not a requirement by code at that time in our area.
So, your question could read two different ways:
Should my ducts have sealant (as in, would they be more efficient)? My power company says yes.
Should my ducts have sealant (as in, was somebody negligent in complying with the code)? Maybe, depending what the code said when your house was built.
RetiredATC
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And there are other ways to seal ducts to prevent air exfiltration than with a mastic type material. – SteveSh Jul 25 '22 at 14:37
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Should the internals of a register where connections are made have gray duct sealant?
Not typically, no.
Duct sealant, or mastic, is applied to the exterior of the joints. You don't want it on the inside because its texture would have a tendency to trap dust and introduces turbulence which reduces airflow.
If you must apply mastic to the inside due to accessibility issues then read the label and make sure it's non-toxic. It will smell for a few days until it fully cures.
MonkeyZeus
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My power company recommended that I take a bucket of mastic and a cheap work glove and smear it around the inside of the duct/register junction. I guess there are different recommendations from different folks. – RetiredATC Jul 25 '22 at 17:06
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I guess you would have to ask them. Perhaps the techniques have changed. I did post that it was in 1994. – RetiredATC Jul 25 '22 at 22:12
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@RetiredATC Sure, what's their number? Also, you wouldn't happen to have an operational 1982 DeLorean kicking around, would you? – MonkeyZeus Jul 26 '22 at 20:02