Tricky Transitions in Commercial Roofing

Detailing the Differential
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Webinar On-Demand
Sponsored by GAF
Presented by Jennifer Keegan, AAIA, and Kristin Westover, PE

Learning Objectives:

  1. Discuss requirements to manage moisture, air, vapor and thermal continuity.
  2. Evaluate code requirements and how to achieve compliance.
  3. Discuss the “whys” behind the details for these tricky transitions.
  4. Review the importance of coordination and execution.


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A typical roof can be riddled with tricky transitions that require careful thought towards detailing. Transitions not only need to consider the integration of different materials, but also the continuity of the control layers—water, air, thermal and vapor. There are a few tricky transition areas that can be overlooked or improperly detailed in the design process, and are sometimes left for the contractor to “figure out.” Some of these overlooked and underappreciated details include: steep-slope to low-slope integration, rising walls, clerestories, parapets and drainage. This webinar will explore some of the considerations to properly detail these tricky transitions, including commentary on installation coordination and execution.

Detailing the Differential


Jennifer Keegan is the Director of Building & Roofing Science for GAF, focusing on overall roof system design and performance. Jennifer has over 20 years of experience as a building enclosure consultant specializing in building forensics, assessment, design and remediation of building enclosure systems. She provides technical leadership within the industry as the Chair of the ASTM D08.22 Roofing and Waterproofing Subcommittee, and the education chair for IIBEC; and as an advocate for women within the industry as an executive board member of National Women in Roofing and a board member of Women in Construction.


Kristin Westover, P.E., LEED AP O+M, is a Technical Manager for Specialty Installations for Low-slope Commercial Roofing Systems at GAF. She has experience with a wide variety of projects in the civil engineering consulting industry specializing in repair and restoration of existing buildings, primarily for commercial buildings and high rise residential structures. Kristin’s project expertise includes roofing, waterproofing, facades, parking garages, and pavements. She has performed assessments, written specification and design documents, provided bidding services oversight, and performed construction contract administration. Kristin also has experience in arbitration and litigation support as well as LEED O+M certification for existing buildings.


GAF | Siplast The Building and Roofing Science team offers regional expert building enclosure collaboration through design, specification, and educational support for customers of GAF and Siplast, both Standard Industries companies. GAF is North America’s largest roofing manufacturer with more homes and businesses in the U.S. protected by a GAF roof than any other product. Siplast, a leader in building enclosure systems, offers a portfolio of advanced, high-performance SBS-modified bitumen, PMMA liquid-applied, PVC KEE, lightweight insulating concrete, wall air & water barrier systems, and amenity/vegetated systems.


Originally published in July 2021