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 06-24-2012, 01:48 PM   #16
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Share |
Default

Insulation around skylight tunnel


Quote:
Originally Posted by sbkim View Post
Thank you! Great info but I am still dazed by all of the info... If you don't mind can I confirm a few takeaways from this post?

1. If I decide to use foam board, do I not use unfaced batt of R13 for 2x4 wall?---- correct.

2. R13 + R5 = R18 (foam board) < R21 ... I guess eliminating air movement is more important than just R value for this application? ----- correct. I just want to ensure no condensation along the shaft and to keep the cold/heat out as much as possible.------ the f.b. will warm the cavity condensation free.

3. If I decide to go with coated Kraft paper batt (R21) which sticks out a bit, can I still wrap it with Tyvek? I feel as though I might be "squeezing" the insulation while wrapping/taping...----- the minimal compressing, if you don't wrap it snug, will hardly lose more R-value than you are gaining by preventing wind-washing of the batts.

Thank you
My answers are in red, above.

Gary
P.S. FYI to all members; when a poster asks a question/s with a "quote" present from a previous post, proper forum etiquette is to wait on the member quoted to answer first, then cover anything pertainent with your answer. This is the primary use of the "quote" button/box- to direct it back to the original poster. Good manners are important everywhere, even on forums, otherwise it comes off as rude.

__________________
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
Old 06-25-2012, 07:11 AM   #17
Member
 
Join Date: Apr 2012
Posts: 153
Default

Insulation around skylight tunnel


You guys are amazing. I can't thank you enough for everyone's insight.
sbkim is offline   Reply With Quote
Old 06-25-2012, 07:53 AM   #18
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: VA, MD, DC
Posts: 5,659
Default

Insulation around skylight tunnel


Good luck.

Foam is the way to go at the end of the day and especially in these cases.
Windows on Wash is online now   Reply With Quote
Old 06-25-2012, 09:11 AM   #19
Member
 
Join Date: Apr 2012
Posts: 153
Default

Insulation around skylight tunnel


Thank you! Yes, it definitely sounds like foam is way to go. Unfortunately, it looks like Thermax is a bit hard to find. I am curious if Tuff-R will work just as well but am curious if I need to provide some fire proofing....

Quote:
Originally Posted by Windows on Wash View Post
Good luck.

Foam is the way to go at the end of the day and especially in these cases.
sbkim is offline   Reply With Quote
Old 06-25-2012, 09:28 AM   #20
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: VA, MD, DC
Posts: 5,659
Default

Insulation around skylight tunnel


Check with the code enforcement officer but any good XPS or PolyIso will work just fine.

Worst case scenario you will have to cover it with some drywall for an approved ignition barrier.

Most guys will also let fiberglass suffice.
Windows on Wash is online now   Reply With Quote
The Following User Says Thank You to Windows on Wash For This Useful Post:
sbkim (06-25-2012)
Old 06-26-2012, 12:11 AM   #21
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Insulation around skylight tunnel


As Windows said, check locally with AHJ. The foamboard may not need covering IF you meet the requirements: http://dow-styrofoam.custhelp.com/ap...KkNueDl5R2s%3D

4.4.2: http://www.icc-es.org/reports/pdf_fi...S/ESR-2670.pdf

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
The Following User Says Thank You to Gary in WA For This Useful Post:
sbkim (06-26-2012)
Old 06-26-2012, 02:19 PM   #22
Member
 
Join Date: Apr 2012
Posts: 153
Default

Insulation around skylight tunnel


Quick update. I have a good news and sort of bad news. Good news is builder agreed to increase framing to allow R21 (I am sure he will find a way to charge me for this) but the bad news is that insulation guy is saying I need vapor barrier on the warm side even with the foam board?! Is this accurate? I thought unfaced was recommended.

Thanks again!
sbkim is offline   Reply With Quote
Old 06-26-2012, 02:52 PM   #23
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Insulation around skylight tunnel


He needs to reboot..... In my post #11, under "are dew-point calcs..." last paragraph of link.http://www.greenbuildingadvisor.com/...ally-necessary

Put 2" f.b. and latex paint inside, your f.g.batts, you'll meet code requirements: http://www.buildingscience.com/docum...r-requirements

Further reading for him to up-date his databases: http://www.ecodes.biz/ecodes_support...e_Resource.pdf

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
Old 06-26-2012, 03:44 PM   #24
Member
 
Join Date: Apr 2012
Posts: 153
Default

Insulation around skylight tunnel


Hi Gary - thank you for the info. Are there any issues with using kraft faced with my setup but this time just going with 1" foam board... Sorry for so many questions!
sbkim is offline   Reply With Quote
Old 06-26-2012, 11:43 PM   #25
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Insulation around skylight tunnel


The paper faced is 1+ perms, the 1" f.b. (if Dow XPS) is 1.1, no problem. Here, if worried: under "Misconception of double-vapor barriers"; https://docs.google.com/viewer?a=v&q...4EyM707m0gPdXQ

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
Existing blow in insulation vs new insulation - Keep or redo? Jaxx Insulation 9 01-17-2014 08:26 AM
Several Insulation Quotes, Big Decisions to make knotquiteawake Insulation 2 05-04-2012 11:16 AM
Garage Insulation yamster Insulation 0 07-01-2011 01:30 PM
Rafter Vents and Insulation nofx1981 Roofing/Siding 15 03-10-2010 08:14 PM
Cold bathroom toeey1 Roofing/Siding 5 02-10-2010 07:29 PM




Top of Page | View New Posts

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