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 Washington Administrative Code (Last Updated: November 23, 2016)
 Title 51. Enterprise Services, Department of (Building Code Council)
 Chapter 51-11R. State Building Code adoption and amendment of the 2015 edition of the International Energy Conservation Code, Residential.

  Section 51-11R-40211. Table R402.1.1—Insulation and fenestration requirements by component.  

Latest version.
  • TABLE R402.1.1
    INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENTa
    For SI:
    1 foot = 304.8 mm, ci = continuous insulation, int = intermediate framing.
     
    a R-values are minimums. U-factors and SHGC are maximums. When insulation is installed in a cavity which is less than the label or design thickness of the insulation, the compressed R-value of the insulation from Appendix Table A101.4 shall not be less than the R-value specified in the table.
     
    b The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration.
     
    c "10/15/21+TB" means R-10 continuous insulation on the exterior of the wall, or R-15 on the continuous insulation on the interior of the wall, or R-21 cavity insulation plus a thermal break between the slab and the basement wall at the interior of the basement wall. "10/15/21+TB" shall be permitted to be met with R-13 cavity insulation on the interior of the basement wall plus R-5 continuous insulation on the interior or exterior of the wall. "10/13" means R-10 continuous insulation on the interior or exterior of the home or R-13 cavity insulation at the interior of the basement wall. "TB" means thermal break between floor slab and basement wall.
     
    d R-10 continuous insulation is required under heated slab on grade floors. See R402.2.9.1.
     
    e There are no SHGC requirements in the Marine Zone.
     
    f Reserved.
     
    g Reserved.
     
    h Reserved.
     
    i The second R-value applies when more than half the insulation is on the interior of the mass wall.
     
    j Reserved.
     
    k For single rafter- or joist-vaulted ceilings, the insulation may be reduced to R-38.
     
    l Reserved.
     
    m Int. (intermediate framing) denotes standard framing 16 inches on center with headers insulated with a minimum of R-10 insulation.
     
    n Log and solid timber walls with a minimum average thickness of 3.5 inches are exempt from this insulation requirement.
    [Statutory Authority: RCW 19.27A.020, 19.27A.045, 19.27A.160, and 19.27.074. WSR 16-02-127, § 51-11R-40211, filed 1/6/16, effective 7/1/16. Statutory Authority: RCW 19.27A.025, 19.27A.045, and 19.27.074. WSR 13-20-121, § 51-11R-40211, filed 10/1/13, effective 11/1/13. Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. WSR 13-04-055, § 51-11R-40211, filed 2/1/13, effective 7/1/13.]
RCW 19.27A.020, 19.27A.045, 19.27A.160, and 19.27.074. WSR 16-02-127, § 51-11R-40211, filed 1/6/16, effective 7/1/16. Statutory Authority: RCW 19.27A.025, 19.27A.045, and 19.27.074. WSR 13-20-121, § 51-11R-40211, filed 10/1/13, effective 11/1/13. Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. WSR 13-04-055, § 51-11R-40211, filed 2/1/13, effective 7/1/13.