Interpretation #6998

Section R4409.5.1.1 allows the studs in exterior walls to be less than 2 x 6 only if designed by rational analysis by a licensed professional engineer or architect proficient in structural design. Rational analysis must demonstrate compliance with the structural requirements of R4403. Minimum sizes may not be sufficient in all cases; therefore, a rational analysis is required to ensure design loads are complied with. Compliance with R4403, R4409 and all of the other conditions contained in section R4403.16.4 (2) is the means to obtain an exemption from the testing requirements of section R4403.16.1.