Sealing Sheet Metal Duct

Old 02-10-10, 03:05 PM
Thread Starter
Join Date: Feb 2010
Posts: 18
Received 0 Votes on 0 Posts
Sealing Sheet Metal Duct

I'm in the process of finishing my basement of a 8 month old house. I have gas forced air with sheet metal duct all the way through. My question is about sealing the joints, which I would like to do before I drywall the ceilings. Also this is all for duct that runs in interior space.

Will aluminum foil tape work or do I need to use mastic? Most might say the mastic, but I've seen the aluminum foil tape hold on for many many years on other house for patch purposes and such. The tape would go faster and cheaper and less messy. Thanks
Old 02-10-10, 03:40 PM
Join Date: Oct 2008
Location: New England
Posts: 10,531
Received 42 Votes on 38 Posts
I'm one who always told people to use the duct mastic, until I got around to using some myself. Slow and messy. It also makes it hard to make changes. If the sealing is inside the heated envelope, it doesn't create as many problems as if it were in an attic or unheated crawl space. The tape will do a good job and like you said, I've seen some old foil tape still holding well.


Old 02-10-10, 04:43 PM
airman.1994's Avatar
Join Date: Dec 2005
Location: VA
Posts: 5,795
Received 8 Votes on 8 Posts
Using duct seal will be faster than using tape. Duct seal is so thick it would be hard to make a big mess. Duct seal and a chip brush $15 Foil tape $9 not real money savings. You would save that in the time.
Old 02-11-10, 07:58 PM
Jarredsdad's Avatar
Join Date: Oct 2002
Location: Troy, VA
Posts: 1,527
Received 0 Votes on 0 Posts
Overkill, but I like to seal tight with tape and then duct seal over that. Especially if it's going to be behind drywall. Call backs are a B****, even worse at your own house.
Old 02-14-10, 11:55 AM
Join Date: Jan 2010
Location: Bartow fl
Posts: 27
Received 0 Votes on 0 Posts
Tape then Mastic all the way.. Just dont mastic the doors on your unit lol...

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: