Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-24-2012, 12:40 PM   #1
Member
 
Join Date: Aug 2012
Posts: 44
Share |
Default

Repairing a few leaks on start collar - Foil Tape or Mastic?


I am up in the attic looking to repair a few leaks in my HVAC ducting. The system is 8 years old and it looks to be in pretty good condition. All the supply ducts are fully wrapped with R4.2 (yes I know it should probably be R6 or R8 these days) with no noticeable leaks (hand test with piece of toilet paper). I am doing this ahead of a contractor coming to do air sealing and cellulose in the attic.

The primary leak I can see is where someone stepped on the supply duct exiting the main rectangular supply trunk, and the round "collar" has basically dislodged by about 3/4 of an inch. Nice gush of A/C air helping to cool my attic!

It looks like I can physically re-insert the collar and then maybe put a 2/4 or something under the duct so it has less chance of being pulled down again. But for sealing that whole collar.....should I cut away the foil/fiberglass insulation in that area then use foil tape to seal it up? Or mastic/mesh tape?

Everything I've read seems to say mastic/mesh is the "gold standard" but I'm thinking that foil tape might actually be better at helping the joint to resist pulling apart again in the future? I've never worked with mastic before but I sort of envision it not having structural strength and just splitting open, or sliding off one piece, if the duct was ever stressed again.

From a neatness standpoint I'd prefer the foil tape if you think it would hold well and stay sealed. I was thinking of going over it in both directions including a longer piece to hopefully add strength to the joint to prevent it from being pulled out again. I don't see where I can really use sheet metal screws to keep the thing attached to the trunk.

Hogan773 is offline   Reply With Quote
Old 08-24-2012, 04:40 PM   #2
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,630
Default

Repairing a few leaks on start collar - Foil Tape or Mastic?


need to check 360 degrees around the duct connected to the unit .mastic brush on sealer i the way to go forget duct tape...you need all the supply air to be delivered to the spac with no leakage in the dut run out in the attic..and heck that return duct need to suck/return space air not attic air at 85F

biggles is offline   Reply With Quote
Old 08-24-2012, 05:22 PM   #3
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,814
Default

Repairing a few leaks on start collar - Foil Tape or Mastic?


Use mastic tape.
beenthere is offline   Reply With Quote
Old 08-25-2012, 08:19 AM   #4
Member
 
Join Date: Aug 2012
Posts: 44
Default

Repairing a few leaks on start collar - Foil Tape or Mastic?


Thanks for the replies. I didnt see mastic tape at my Menards. Maybe they only sell it at contractor suppliers.

I bought some FOIL TAPE (no, I wasn't going to use regular duct tape). The contractor used foil tape in our basement (finished) and it is still holding up after 8 years. I know plain old duck tape sux (people should not call it duct tape...too misleading)

I also bought some mastic but I forgot to get some fiberglass mesh tape to embed in it....I assume that is another way of making "mastic tape"
Hogan773 is offline   Reply With Quote
Old 08-25-2012, 08:39 AM   #5
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,814
Default

Repairing a few leaks on start collar - Foil Tape or Mastic?


http://www.mhparts.com/proddetail.php?prod=H-1038-52

The above is just one brand of it.
beenthere is offline   Reply With Quote
Old 08-25-2012, 09:48 AM   #6
I'm Your Huckleberry
 
Join Date: Mar 2011
Posts: 5,663
Default

Repairing a few leaks on start collar - Foil Tape or Mastic?


Duct tape is for repairing/extending duct and works very well for it's designed purpose. The inner liner of the duct should be duct taped to the collar. Foil tape/mastik is used to seal the collar to the box.
__________________
Thanks.
Doc Holliday is online now   Reply With Quote
Old 08-25-2012, 09:50 AM   #7
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,814
Default

Repairing a few leaks on start collar - Foil Tape or Mastic?


"Duct" tape was never intended to be used on duct work.
beenthere is offline   Reply With Quote
Old 08-25-2012, 09:55 AM   #8
I'm Your Huckleberry
 
Join Date: Mar 2011
Posts: 5,663
Default

Repairing a few leaks on start collar - Foil Tape or Mastic?


Nor is any common ducK tape that is not UL listed.

__________________
Thanks.
Doc Holliday is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
First time taping - Tape has air under it theedudenator Drywall & Plaster 16 04-21-2010 11:13 PM
Frozen Hot Water Pipes TravisW Plumbing 11 12-10-2009 05:26 PM
Repairing drywall tape bcouch Drywall & Plaster 2 09-08-2009 03:19 PM
Regular Foil Ducting Tape handy man88 HVAC 7 07-17-2009 03:39 PM
Repairing where paint peeled off with masking tape? Doug Crf Painting 4 04-29-2006 10:47 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.