The manual's latest update

NRCA's latest roofing manual addresses flashings and condensation and air leakage control

In January, NRCA published The NRCA Roofing Manual: Architectural Metal Flashing and Condensation and Air Leakage Control—2018, its latest volume of The NRCA Roofing Manual. This volume revises, updates and supersedes the 2014 version. Following is a brief overview of some of the more significant changes in the new manual.

The changes

The most notable change between the 2014 and 2018 volumes is the elimination of the 2014 volume's Reroofing Section. Beginning with The NRCA Roofing Manual: Membrane Roof Systems—2015 and continuing with The NRCA Roofing Manual: Metal Panel and SPF Roof Systems—2016 and The NRCA Roofing Manual: Steep-slope Roof Systems—2017, roof system-specific reroofing guidelines are provided within each volume of the manual. For example, reroofing guidelines, including roof system removal and replacement and re-cover criteria applicable to membrane roof systems, is provided in Chapter 9-Reroofing of The NRCA Roofing Manual: Membrane Roof Systems—2015.

In the 2018 manual's Architectural Metal Flashings Section, there are minimal changes.

In Chapter 1-Guidelines Applicable to Metal, zinc-tin-coated steel (Terne II) has been moved to the historical metals section as it no longer is commonly produced; however, it still may be encountered in existing roof systems during repair or reroofing situations.

Figure 1-18-Fasteners Commonly Used with Sheet Metal and Figure 1-19-Guidelines for the Selection of Fasteners Based on Galvanic Action are revised and updated in the 2018 manual to reflect technology advancements.

In Chapter 4-Construction Details, Detail CF-2-Behind Cladding Receiver and Counterflashing and Detail EJ-1 (and EJ-1A)-Roof-to-wall Expansion Joint with T-type Cleat are revised to incorporate taller (4-inch minimum) upturned back legs.

In the Condensation and Air Leakage Control Section, references to code and standard text have been updated to the 2015 editions of the International Building Code,® International Residential Code® and International Energy Conservation Code®; ASHRAE 90.1-2016, "Energy Standard for Buildings Except Low-Rise Residential Buildings"; and ASHRAE 189.1-2014, "Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings."

In Chapter 1-Fundamentals of Condensation and Air Leakage Control, Section 1.2-Principles of Moisture Vapor Movement has been rewritten and new figures added to more clearly explain the principles.

In Chapter 2-Condensation Control for Low-slope Roof Systems and Chapter 3-Condensation Control and Ventilation for Steep-slope Roof Assemblies, step-by-step procedures for determining temperature gradients through low- and steep-slope roof assemblies, respectively, have been added. This information previously had been added to the 2014 volume with the January 2016 interim update.

In the Appendixes Section, Appendix 4-NRCA Technical Dictionary is significantly expanded from the Glossary in the 2014 volume. The new technical dictionary provides terms and definitions applicable to all NRCA technical publications. The previous glossary's terms and definitions only applied to The NRCA Roofing Manual. As a result, 88 new terms and definitions have been added to the 2018 manual, bringing the number of NRCA technical terms and definitions to 863.

A new appendix, Appendix 5-Considerations for Lightning Protection Systems, provides general information about lightning protection systems (LPSs) that sometimes interface with roof assemblies, descriptions of recognized certification programs for LPS installation and installers, and NRCA's recommendations for what to do when LPSs are encountered in roofing projects.

In addition, Appendix 6-History of Manual Updates has been added to the 2018 manual to provide a location for enumerating any upcoming interim updates to the manual.

Get it

I encourage you to get The NRCA Roofing Manual: Architectural Metal Flashing and Condensation and Air Leakage Control—2018 and begin to familiarize yourself with it.

NRCA members receive free access to electronic versions of The NRCA Roofing Manual series, including the new 2018 volume. Members can download the entire manual series as PDF documents at and access it through the NRCA app.

Print versions of all NRCA manuals are available for purchase at

Mark S. Graham is NRCA's vice president of technical services.

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