| Posted By |
|
|
|
| | |
|
Peoria, Arizona
Posts: 131
Joined: Feb, 2004
|  offline
|
|
|
|
| |
 |
Lafayette, Louisiana
Posts: 3919
Joined: Nov, 2009
| offline
|
|
 Sprayed Foam Attic #3
[#2] Posted: 01/28/2012 - 7:42:39 PM |  |  |
|
According to Mason Knowles in a September 2010 JLC article, the R-value of SPF depends on the density of the foam and the blowing agent used. Low density foam in the 0.4 to 0.6 lb/cubic foot range typically has an R-value of 3.5 to 3.8 per inch. Densities of 1.5 to 2.0 lb/cubic foot yields R-values of 5.8 to 6.8.
So folk, git dat density and dat thickness and figure dem out.
Marc
PS: second paragraph ain't by Knowles, none.
|
"If Guam gets too overpopulated, it might tip over."
Congressman Hank Johnson (D) GA |
| |
|
|
| |
 |
Chicago, IL
Posts: 9553
Joined: Dec, 2003
| offline
|
|
Sprayed Foam Attic #3
[#3] Posted: 01/29/2012 - 10:38:50 AM | | |
|
Closed cell foam is hard, almost a shiny film on top. Very hard to tear off a chunk. It's Great Stuff without the can.
Open cell is kinda......open.....fluffy....you can dig at it with your fingernail and it'll come off in a chunk.
Open cell is about R3 or 4. Closed cell is about R6-ish to 7-ish.
Some of the pics look like closed, some look like open. The underside of the roof shot looks like closed cell.
But, don't go by my guessing @ a pic.
|
Kurt in Chicago
"If I smell it, it goes in the report".............Phillip Smith...2012
|
| |
|
| |
|
|
|
|
|
|
|
1A SF 11.JPG
1A SF 13.JPG
