Foam Insulation In Rafters - Insulation - DIY Chatroom Home Improvement Forum


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

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

Reply
 
Thread Tools Display Modes
Old 03-29-2012, 03:55 PM   #1
Newbie
 
Join Date: Mar 2012
Posts: 3
Rewards Points: 10
Default

Foam Insulation in Rafters


I have 1/2lb foam insulation spayed on my attic roof rafters. Thickness is 6-7" since I cannot see my 2x6s. foam was also spayed on walls of attic space but my builder didnt put any blown in insulation or batt rolls on top celings joists. I live in south Texas where it gets bout 100-105 degrees outside. Will putting unfaced R30 benefit me in any way on energy bills. There is no ventilation on the attic.

Advertisement

marine02ss is offline   Reply With Quote
Old 03-29-2012, 05:53 PM   #2
Member
 
Join Date: Dec 2008
Location: Fairbanks, AK
Posts: 1,847
Rewards Points: 1,000
Default

Foam Insulation in Rafters


You apparently agreed to have a conditioned attic, which means it is living space, just like your living room. There is no point in adding insulation between conditioned rooms, unless you want to reduce noise a somewhat. If they used open cell foam, it probably needs to be painted w/ a vapor retarding paint. Talk to the contractor about which they used. If they said nothing, it is probably closed cell. Buildingscience.com, greenbuildingadvisor.com, and other places have good resources on this type of installation.

Advertisement

jklingel is offline   Reply With Quote
Old 03-29-2012, 07:27 PM   #3
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: Washington DC Metro Area (VA, MD, DC)
Posts: 7,101
Rewards Points: 3,258
Default

Foam Insulation in Rafters


6-7" of open cell probably isn't enough in this case.

You should have at least and R-30 across the roof or at least 8-9".

You could add insulation across the floor if you so desire and it would have some impact.

+1 on checking out building science.com
Windows on Wash is online now   Reply With Quote
Old 03-30-2012, 04:38 PM   #4
Newbie
 
Join Date: Mar 2012
Posts: 3
Rewards Points: 10
Default

Foam Insulation in Rafters


Are you saying to put batt insulation directly under the foam or on the ceiling joist where the sheetrock is? Another ? would I use unface batt or faced batt because I know the foam is already acting a a vapor barrier.
marine02ss is offline   Reply With Quote
Reply


Thread Tools
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
Insulating your attic Bob Mariani How To Guides 5 07-07-2013 09:49 PM
Basement Ext Wall - Will Rigid Insulation allow my wall to dry inward? COLORADOMTNMAN Insulation 10 01-15-2012 11:09 PM
Vapor sealing with open cell foam insulation PerpetuallyRepairing Insulation 6 12-17-2011 10:16 PM
Hybrid wall insulation consisting of 2" rigid foam + 2x4 fiberglass batts? TitaniumVT Building & Construction 15 09-14-2010 03:50 AM
Using rigid foil faced foam insulation Ronnie1a Remodeling 1 01-22-2008 02:23 PM




Top of Page | View New Posts