Insulation, Radiant and Vapor Barriers - Calculate R value?

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DavidJ
10-15-03, 02:42 PM
Can anyone let me know what the R value is of my existing walls?

They consist of (from the outside):

2.5" wide brick
1" air space
vapor barrier
3/4" sheeting (ship lap)
3.5" stud space (no insullation)
1" gypsum wall board

I am trying to determine if it is worth it to blow in insullation. House is in Seattle with moderate winter temps.

Thanks

David J

chfite
10-15-03, 06:32 PM
I don't know what an energy use survey costs out there but evaluation of where and how much heat is lost might be valuable. Your local utility company may have some data on the effectiveness of certain types of insulation for your local.

Here are some tables and studies that may help.

http://coloradoenergy.org/procorner/stuff/r-values.htm

http://hem.dis.anl.gov/eehem/99/991110.html

http://hem.dis.anl.gov/eehem/95/950303.html

Hope this helps.
brickeyee
10-16-03, 07:29 AM
Around R 4.5. The structure without the 1 inch air gap is 3.7, and you gain about 0.8 for the 1 inch air gap.