Summaries of 2018 Foam Plastics Code Change Proposals

by Jay Crandell, P.E.


The following code change proposals support safe, durable and energy efficient construction. These 2018 International Building Code (IBC) changes have been submitted by various foam plastic insulation associations, including the Foam Sheathing Committee (FSC) of the American Chemistry Council (ACC), XPSA, PIMA, and CPI.  The proposals addressed below are published in the ICC Group A hearing agenda available at (individual proposals have been extracted and are linked to in the summaries below).   

Collectively, these proposals provide for the appropriate use of foam plastic insulation materials on building envelopes and, in general, help to ensure coordination between the energy code and building code for safe, durable, and energy efficient construction. 

  • G6-18 (XPSA) – Adds the definition for “insulating sheathing” to IBC to address various applications to walls, floors, roofs, and foundations for buildings constructed within the scope of the IBC.
  • FS93-18 (FSC) – Adds “enhanced weather protection” provisions for walls in Chapter 14 of the IBC to addresses two significant moisture-durability factors:  (1) regions with high wind-driven rain hazards and (2) inward vapor drives with claddings that tend to “store” rain water (e.g., stucco, adhered veneer, etc.) 
  • FS106-18 (FSC) – Coordinates IBC and IRC water-resistive barrier requirements, particularly in regard to installation requirements for traditional No.15 asphalt felt which is the only WRB material specifically recognized in Section 1403.2 of the IBC.
  • FS107-18 (XPSA) – Adds language to ensure that “other approved” (i.e., alternatives to No. 15 felt) water-resistive barriers are installed in accordance with the manufacturer’s installation instructions which will vary by product type and approved methods for resisting rain water intrusion.
  • FS113-18 (FSC) – Adds a reference in Chapter 14 of the IBC to additional cladding connection requirements that are found in Chapter 26. This will aid in providing attachment considerations and options for various types of claddings installed over FPIS.
  • FS117-18 (FSC) – Re-formats vapor retarder provisions in Section 1404.3 of the IBC to make code-compliant vapor retarder selections more transparent and user-friendly by use of simple “look-up” tables based on climate zone and vapor retarder classes.
  • FS120-18 (FSC) – Co-sponsored by Home Innovation Research Lab and based on research for DOE’s Building America program, this proposal provides guidance to ensure appropriate use of continuous insulation with Class II vapor retarders to ensure proper moisture management of walls and to better coordinate with insulation requirements of International Energy Conservation Code (IECC).
  • FS121-18 (PIMA) –  Corrects (deletes) a provision recently added to the code that inappropriately limits vapor retarder options with continuous insulation and, consequently, has caused conflict with the IECC insulation requirements and successful water vapor control design practices for assemblies with continuous insulation (e.g., see FS120-18).  
  • FS122-18 (CPI) – Clarifies a lengthy footnote in Table 1404.3 for Class III vapor retarders by moving it into the text of the code to more transparently address use of spray foam for moisture control. It also acknowledges the common and successful practice of using spray foam in cavities in combination with exterior continuous insulation to control moisture per Table 1404.3.2 of the IBC. This also satisfies insulation and air barrier provisions of the IECC.  Also see FS129-18, which is a similar proposal by CPI.
  • FS123-18 (FSC) – Clarifies that use of Class III vapor retarders are permitted in Climate Zones 1-3 as intended, but not explicitly stated in the code or Table 1404.3.2, which only addresses colder climate zone applications.
  • FS125-18 (FSC) – Expands application of Table 1404.3.2 Class III vapor retarders to include all of Climate Zone 4, not just Marine 4 as also proposed by others in proposal FS126-18 (Conner & Lstiburek).  This will ensure consistent performance and water vapor control across all of Climate Zone 4 in cases where a Class III vapor retarder is used.
  • FS127-18 (FSC) – Makes a correction to Table 1404.3.2 Class III vapor retarders to separate requirements for Climate Zone 8 from combined Climate Zone 7/8 to ensure adequate water vapor control and moisture management in the more severe cold conditions of Climate Zone 8.  Also consistent with another proposal, FS128-18 (Conner & Lstiburek).
  • FS130-18 (CPI) –  Clarifies the footnote to Table 1404.3.2 Class III vapor retarders such that combining spray foam (cavity insulation) and continuous insulation R-values is permitted only for compliance with the moisture control purpose of the table, not for determining R-values for energy code compliance.
  • FS131-18 (XPSA) – Ensures that paints used as vapor retarders per Section 1404.3.3 comply with requirements for the vapor retarder class and are applied in accordance with the manufacturer’s installation instructions.
  • FS133-18 (PIMA) – Coordinates IBC and IRC flashing requirements by permitting flashing to the surface of the water-resistive barrier for drainage as necessary and not just to the exterior of the cladding.
  • FS157-18 (XPSA) – Re-organizes and clarifies fire-safety requirements in Section 2603.5 for foam plastics used in exterior wall assemblies of Type I, II, III, and IV construction.  This proposal will help promote enforcement and compliance with important fire-safety requirements. Overall, the fire-safety requirements of Chapter 26 ensure appropriate and safe use of foam plastics and are known to be some of the most thorough and effective provisions controlling the use of any combustible building material.      

So, if you’re planning to attend the ICC Group A code hearings in Columbus, OH on April 15-23 or planning to vote on-line following the hearing, you might want to consider supporting these proposals to improve and strengthen the IBC.  

PDF icon g6-18.pdf26.96 KB
PDF icon fs93-18.pdf87.56 KB
PDF icon fs106-18.pdf32.97 KB
PDF icon fs107-18.pdf31.72 KB
PDF icon fs113-18.pdf27.05 KB
PDF icon fs117-18.pdf91.26 KB
PDF icon fs120-18.pdf56.76 KB
PDF icon fs121-18.pdf28.83 KB
PDF icon fs122-18.pdf59.59 KB
PDF icon fs123-18.pdf26.54 KB
PDF icon fs125-18.pdf37.86 KB
PDF icon fs127-18.pdf65.92 KB
PDF icon fs130-18.pdf58.38 KB
PDF icon fs131-18.pdf32.58 KB
PDF icon fs133-18.pdf32.27 KB
PDF icon fs157-18.pdf50.54 KB