Core TradesQuestion 112 of 700
CALCULATION: A wall assembly has three layers with R-values of R-4 (sheathing), R-13 (cavity), and R-0.68 (interior finish). Ignoring air films, what is the total nominal R-value?
a.R-13
b.R-15
c.R-17.68
d.R-20
Explanation
For layers in series, R-values add: 4 + 13 + 0.68 = 17.68. Answer 13 counts only the cavity; 15 and 20 add incorrectly.
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