Helpful? 0

How much air does dense-packed cellulose leak?

I've been thinking a lot about dense packed cellulose and reading up on it's various properties. I found an excellent discussion on this same message board: http://www.greenbuildingadvisor.com/community/forum/energy-efficiency-an....

What I've learned on this discussion is that desnse packed cellulose is not considered an air barrier because it does not meet the ASTM standard for an air barrier at 0.02 l/sec-m2 or 0.004 cfm/sf @75Pa. This makes sense to me. What I'm trying to find out is if there have been any studies published about how air permeable dense packed cellulose actually is. I'd like to see numbers, and especially numbers expressed in the same form as they are expressed when talking about actual air barriers. Any ideas?

Thanks

Josh Engle

Asked by Josh Engle
Posted Wed, 06/25/2014 - 07:46
Edited Wed, 06/25/2014 - 09:25

Tags:

2 Answers

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.
Helpful? 0

Josh,
Here is an article that address your question:

Don't Be Dense—Cellulose and Dense-Pack Insulation:

"Empty walls (a wood frame wall with plywood sheathing or a wood frame wall with board sheathing, building paper and interior gypsum board) vary [in air leakage rates] between 0.4 to 4 cfm/ft2 at 0.3 in. w.c. (2 to 20 L/s·m2 at 75 Pa) leakage. When we blow them with insulation (we dense pack them to around 3.5 lb/ft3 [56 kg/m3] density), the leakage drops to 0.04 to 0.2 cfm/ft2 at 0.3 in. w.c. (0.2 to 1.0 L/s·m2 at 75 P.5). This is unbelievably impressive.... As impressive as these numbers are, an order of magnitude reduction in leakage, we need to put these numbers into perspective. Dense pack cellulose and dense pack fiberglass are not air barrier materials, and they do not result in air barrier assemblies."

Answered by Martin Holladay, GBA Advisor
Posted Wed, 06/25/2014 - 09:04
Edited Wed, 06/25/2014 - 09:07.

2.
Helpful? 0

Thanks Martin, that helps a lot.

Answered by Josh Engle
Posted Thu, 06/26/2014 - 07:36

Other Questions in Green products and materials

Thermal energy storage

In Green building techniques | Asked by Jim Pancanke | Oct 21, 14

The Death Of Burberry Sale And How To Avoid It

In PassivHaus | Asked by Lonny Solly | Oct 21, 14

PERSIST vs REMOTE vs SIP ?

In Green building techniques | Asked by Walker Angell | Oct 21, 14

Curbless shower with a PVC liner -- how to terminate the liner at the floor?

In General questions | Asked by john walls | Oct 19, 14

Insulation in old home repair

In Energy efficiency and durability | Asked by Tom Ives | Oct 21, 14
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!