Concluding Technical Bulletin 2017-2S1 – WSRCA Synthetic Underlayments Testing and Research Project

The WSRCA’s Self‐Adhering Underlayment Slip‐Resistance Research and Testing Project has performed slip‐resistance testing of numerous steep‐slope roofing underlayments.

After receiving reports describing problems with different types of steep-slope roofing underlayment materials over the last few years, and more recently some reported issues with a couple of different types of synthetic underlayments, WSRCA’s Steep-Slope Committee launched an underlayment research and testing project on behalf of its Members. This study, to research the various types of underlayments and their published physical compositions and published performance properties, began during 2013, and continued into 2014. The research then progressed to subject a select group of materials to a series of laboratory tests, followed by on-roof weathering and examinations, and follow-up testing. Testing commenced during 2015, with initial laboratory characterization of ten (10) as-new underlayment materials, then on to full-scale on-roof weather and exposure testing. This integral testing gave rise to more research, and concluding laboratory testing of the as-weathered materials, all of which was completed before Summer of 2016.

Based on the research and testing to date, WSRCA's Steep-Slope Committee has prepared this Concluding Technical Bulletin to share insights gained in the process and to provide guidelines for evaluating a wide contingent of underlayments for potential use in steep-slope roofing systems. This Bulletin also provides suggestions for the industry in an effort to help clarify the wide-ranging and sometimes confusing reported physical properties of the numerous different kinds of underlayment materials currently available on the market.

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WSRCA Steep-Slope Committee Stan Robinson — Chairman: Steep-Slope,  Chris Sprick — Vice Chairman: Steep-Slope, Sprick Roofing Company Don Fry — Fry Roofing, Inc. Everett Martin — Empire Roofing, Inc. Steve Nash - Waterproofing Associates Mike Tory — Tory's Roofing & Waterproofing Jim Carlson — WSRCA Technical Advisor, Building Envelope Technology & Research Steven Elliott — Assistant Technical Advisor, BET-R