[Default] On Sat, 1 Dec 2012 12:49:00 -0800 (PST), a certain
chimpanzee, , randomly hit the keyboard and wrote:

U values... I thought brick/cavity/brick wall was 1.73?

I get something quite different...
Brick Commons - 102mm --- 0.132
Air Cavity - 50mm ------- 0.180
Brick - 102mm ----------- 0.132
Plaster - 6mm ----------- 0.025

Total R Value = 0.469 where U = 1/R = 2.132

You haven't included internal and external surface resistances, which
IIRC add 0.13 & 0.04 m^2K/W respectively to the resistance. There's
also different R-values for the brick on the inner & outer leaves (the
outer is lower due to moisture). Don't know the figure for sure off
the top of my head, but 0.12 m^2K/W springs to mind.
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