Page 10 - Green Builder Magazine June 2015 Issue

R-Value Computation—Insulated Siding

An excerpt from ICC’s Significant Changes to the International Residential Code® (2015)

Significant Changes to the IrC 2015 Edition N1102.1.3 ■ R-Value Computation—Insulated Siding 211

ChANgE TypE: Modification N1102.1.3

ChANgE summAry: The code now allows insulated siding to be used R-Value Computation—
in the calculation for satisfying the wall insulation R-value. The labeled insulated siding
R-value for the siding must be reduced by R-0.6 for calculation purposes.

2015 CodE: N1102.1.3 (r402.1.3) R-value Computation. In- Significant Changes to the
sulation material used in layers, such as framing cavity insulation and International Residential Code®
insulating sheathing or continuous insulation, shall be summed to com- (2015) is a valuable tool for
pute the corresponding component R-value. The manufacturer’s settled transitioning to the new code.
R-value shall be used for blown insulation. Computed R-values shall not The book lists the Change
include an R-value for other building materials or air films. Where insu- Type, Change Summary and
lated siding is used for the purpose of complying with the continuous Change Significance for the
insulation requirements of Table N1102.1.2, the manufacturer’s labeled most important changes allowing
R-value for insulated siding shall be reduced by R-0.6. readers to save substantial time
learning new requirements. This
N1101.6 (r202) defined Terms. publication may be purchased by
visiting the ICC online store at
iNsuLATEd sidiNg. A type of continuous insulation with manufacturer- www.iccsafe.org/GBchanges.
installed insulating material as an integral part of the cladding product
having a minimum R-value of R-2.

N1102.1.3 continues

Siding

Min. R-2 rigid
insulation integral
with siding
material

© International Code Council

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# 153129 Cust: Cengage Au: IRC Pg. No. 211
Title: International Residential Code 2015 Edition