What is the R Value of a 2x6 dense packed cellulose wall?

I am reviewing the requirements of the new Maine Uniform Building and Energy Code that goes into effect 12/1/2010.  The required R value for a wood framed wall is R20. If I assume the Dense Packed Cellulose has an R value of 3.4 per inch and a 2x6 is really only 5.5" deep, then 5.5" of cellulose is only R18.7 which doesn't quite meet the standard.

I could put in R21 fiberglass and meet the standard, but I am sure the cellulose would out perform the glass in the real world.

How does everyone else view this subject?

Views: 3642

Reply to This

Replies to This Discussion

According to National Fiber's website a 2 x 6 wall at 5.5 " thick has an R value of R20 when dense packed at 3.5 lbs per cubic foot. The reason the Code has a minimum wall insulation requirement of R20 is because thats as good as it gets with celluloce, if the cellulose manufacturers hadn't been allowed their input the minimum would be R21 (fiberglass batts).
Thanks for the reply Scott. I found that on the National Fiber site after I posted the message.

What approach do you plan to take to get R49 in a cathedral ceiling where the slope area is greater than 500 ft2 or 20% of the total ceiling area?

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Michael Dunseith posted a status
2 minutes ago
Rob Madden, Solar Home Broker posted a blog post

Phoenix 3rd Quarter Solar Resale Statistics Continue to Impress

Phoenix solar home sales were up during the third quarter of 2014, including the resale of homes…See More
16 hours ago
Everblue posted a status
"Green job alert! Energy Auditor in Baltimore, MD with Advanced Green Home Solutions. Check it out: http://bit.ly/1xhQuXO"
17 hours ago
Chris Clay replied to Isaiah Borel's discussion Blown Cellulose VS Blown Fiberglass in the Attic
"The Cold Climate Housing Research Center in Fairbanks, AK has alot of information about this…"
18 hours ago
Richard L. Sanderson replied to Bud Poll's discussion Inconsistant Local Authority
"Bud: I like the idea of a third party review board. My own experience in local government is that…"
yesterday
Matthew Lutz commented on Kaplan Clean Tech's blog post The Difference Between Home Inspection and Energy Auditing [Infographic]
"I would have to agree with Steve on this.  I am a Certified Energy Manager and have performed…"
yesterday
Matthew Lutz joined Diane Chojnowski's group
Thumbnail

Hall of Shame

In this group, members share an array of images from the field, showing the kinds of issues…See More
yesterday
Matthew Lutz replied to Kari Sauder's discussion Easy Water Heater Venting in the group Hall of Shame
"I have been in the HVAC trade since 1986. I have recently completed a Home or Real Estate…"
yesterday

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service