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

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

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-07-2012, 03:51 PM   #1
Member
 
Join Date: Aug 2011
Location: SE Michigan
Posts: 100
Share |
Default

Can I use ductwork insulation to keep cellulose off attic pipes/vents?


About to blow in cellulose insulation. There's no insulation right now, because I removed it for several reasons. I know I need to prevent the cellulose insulation from resting against the under microwave range exhaust coming from down below up through the roof. (EDIT: Removed "and other pipes" after joecaption's comment.)

I saw in quite a few guides to create an air barrier around these pipes, by fixing a larger sized pipe in place around it, high enough so it would be higher than the insulation. Also making sure the bottom and top of the new pipe were closed off, so insulation wouldn't blow in there.

Instead of doing that, would a foil faced fiberglass R-6 ductwork insulation sleeve do the trick? It's a lot cheaper, and would be a lot easier!


Last edited by darlingm; 01-07-2012 at 04:41 PM. Reason: Removed "and other pipes" after joecaption's comment.
darlingm is offline   Reply With Quote
Old 01-07-2012, 04:06 PM   #2
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 26,166
Default

Can I use ductwork insulation to keep cellulose off attic pipes/vents?


Not sure where you got that info.
Insulation around duct work, and soil pipe vents will do no harm.
If there's big holes around the pipes where they just made the holes to big they should be sealed with expanding foam insulation, in fact before you start blowing it's good policy to seal up any holes in the ceiling before the insulating. If you can see light coming from below such as a round a light fixture or ceiling fan seal it up or there's still going to be an air leak.

joecaption is offline   Reply With Quote
Old 01-07-2012, 04:45 PM   #3
Member
 
Join Date: Aug 2011
Location: SE Michigan
Posts: 100
Default

Can I use ductwork insulation to keep cellulose off attic pipes/vents?


Quote:
Originally Posted by joecaption View Post
Not sure where you got that info.
Insulation around duct work, and soil pipe vents will do no harm.
If there's big holes around the pipes where they just made the holes to big they should be sealed with expanding foam insulation, in fact before you start blowing it's good policy to seal up any holes in the ceiling before the insulating. If you can see light coming from below such as a round a light fixture or ceiling fan seal it up or there's still going to be an air leak.
You know, I'm not sure why I was saying and other pipes too. Guess I've just had too much on my mind, and I'm exhausted.

As far as the under microwave range exhaust goes, however, I've seen many guides say that you have to keep the insulation from touching it. Below is a page from one of the guides that I've seen say this, although I've seen it in others.

I haven't done this before, and certainly can't speak myself as to whether it's necessary.

buildingscience.com Guide to Attic Air Sealing, pg 38:

darlingm is offline   Reply With Quote
Old 01-07-2012, 05:05 PM   #4
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 26,166
Default

Can I use ductwork insulation to keep cellulose off attic pipes/vents?


That's for a pipe for a vent for a gas fireplace or hot water heater.
Any pipe that does not prduce heat can be insulated right up againt it.
Sewer vents, range hood vents, main power pole that goes through the roof, can be insulated direct contact.
If it's PVC or cast iron, steel pipe it's safe.
joecaption is offline   Reply With Quote
Old 01-07-2012, 05:22 PM   #5
Member
 
Join Date: Aug 2011
Location: SE Michigan
Posts: 100
Default

Can I use ductwork insulation to keep cellulose off attic pipes/vents?


Quote:
Originally Posted by joecaption View Post
That's for a pipe for a vent for a gas fireplace or hot water heater.
Any pipe that does not prduce heat can be insulated right up againt it.
Sewer vents, range hood vents, main power pole that goes through the roof, can be insulated direct contact.
If it's PVC or cast iron, steel pipe it's safe.
Ahh, OK, thanks! I figured the range hood vent would be in the same category, figuring it could get pretty hot sometime. Thanks again!
darlingm is offline   Reply With Quote
Old 01-07-2012, 09:16 PM   #6
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Can I use ductwork insulation to keep cellulose off attic pipes/vents?


It probably wouldn't get hot enough to catch insulation on fire, but I would wrap it with some better R-value than 6 (Code minimum, like a "D" in school) for your location. Picture warm moist air (grease from cooking or boiling water) going through a cold (attic temperature) pipe to condense on the inside walls as it streams past. Foil tape or mastic the seams when going through unconditioned spaces (attics) as the BSC article said. Much better to fully insulate (as if it was a wall) the pipe for your location, then to just add the cellulose around it. The pipe insulation will help stop the convection to the roof-top termination hood connected to the pipe in the attic, as well.

Gary

__________________
If any ads are present in my answer above, I do not condone/support/use the product or services listed, they are there against my permission.
Gary in WA is offline   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
Help with complicated insulation project in attic OhmZoned Insulation 12 11-19-2011 08:49 AM
I want more storage in the attic, have loose insulation, is it good? Flooring over? kaitala Insulation 7 11-04-2011 05:11 PM
AC Flex Duct - Suspend above attic insulation or lay it on top? fritzycat1 HVAC 13 08-17-2011 10:19 PM
I'm finding chunks of (cellulose) attic insulation in the A/C registers.... AnotherGuy HVAC 2 04-09-2011 09:34 PM
Attic Foam Board Insulation JasonCA Roofing/Siding 3 10-07-2010 12:56 AM




Top of Page | View New Posts

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