How to fix HVAC Duct Vapor Barrier

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Jan 14, 2013, 11:49 PM

mudgod

How to fix HVAC Duct Vapor Barrier

Hi
I wanted to find out how to patch sections of HVAC insulation where the vapor barrier has torn off. Should I just tape with Flex HVAC tape, get a Radiant barrier, add another layer of insulation w/vapor barrier

Thanks a bunch

Jan 15, 2013, 12:29 AM

joecaption

Confusing, HVAC lines do not use a vaper barrier.
Got a picture.
The ducts need foil tape.

Jan 15, 2013, 08:41 AM

Sparky617

quote:
Originally posted by joecaption:
Confusing, HVAC lines do not use a vaper barrier.
Got a picture.
The ducts need foil tape.

Most duct insulation I've seen has a foil or other covering on it that could be considered a vapor barrier. Here in NC a duct running through an unconditioned crawlspace the insulation would be soaked in the summer time as the moisture in the air condensed on the duct without this covering.

I'd use foil duct tape, definitely not DUCK Tape, a brand of the cloth tape sometimes referred to as duct tape, though it is really not intended for this purpose.

General Disclaimer

Any advice given here is general in nature and is not necessarily valid for your given area. If in doubt check with your local codes enforcement department for what is required when doing electrical, plumbing or structural work on your house. Permits may or may not be required in your area and home owners may not be able to DIY some tasks. I have no way of knowing if you have the skills needed to complete the tasks you are asking about, when in doubt seek professional assistance.

My advice may be worth exactly what you pay me for it. :-) For the record I did not stay in a Holiday Inn Express last night.

Jan 15, 2013, 09:36 AM

mudgod

@Sparky617: That's exactly it. I have ductwork in the attic (unconditioned space) similar to this and it has areas where the insulation is exposed that I wanted to repair.

There are 1 or 2 larger exposed areas, would getting an aluminum foil (similar to a radiant barrier product) to cover and then taping the edges work. I'm going to be using HVAC foil tape to do so

Jan 15, 2013, 10:05 AM

Jaybee

In most cases, you can simply pull the edges of the tear together and tape with foil tape. If larger areas of insulation is missing, then you can use sections of duct-wrap insulation (fiberglass insulation with a foil skin) to fill the holes. All this is held in with foil tape.

If you only have a few small areas, and since duct-wrap usually comes in larger, full rolls, you can get the same effect by patching with regular fiberglass and covering with foil tape.

Mar 12, 2013, 03:13 PM

mudgod

Hi
Just wanted to follow up that I got rolls of insulation for HVAC and cut them to the appropriate size. For smaller tears I just pulled the edges together and used foil tape to hold it all together.

Thanks again for all the help