THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN 12  ONTARIO ROOFING NEWS – FALL 2018 Cover Boards in Commercial Roofing Interface evaluation (IE), which is the intermediate testing between material and system, is essential to assess the interaction of two or more dissimilar roofing materials. Properties, such as peel resistance, which is a localized characteristic among two materials as opposed to the entire system, must be evaluated at its corresponding interface. Assessing the required cover board properties as IE allows for evaluating a cover board with the materials it is intended to protect. The cover board properties that require IE include peel resistance, cover board pull-through, resistance to repetitive loading and dynamic puncture resistance. These properties are essential to determining the protective characteristics of the various cover boards in commercial roofing. Peel Resistance Only IE can quantify the peel resistance of bonded or adhered materials in the face of shear forces. Existing system tests, which include ANSI/FM 4474, “American National Standard for Evaluating the Simulated Wind Uplift Resistance of Roof Assemblies Using Static Positive and/or Negative Differential Pressure,” and CSA A123.21, “Standard Test Method for the Dynamic Wind Uplift Resistance of Membrane Roofing Systems,” simulate uplift forces as opposed to shear forces. IE complements system testing by determining the peel strength of a membrane and cover board and that of insulation and cover board integrated together. Photo 1 depicts a membrane peel failure from a wood fiber board. A peel test for the cover board interfaces will establish the resistance requirement for ensuring cover boards are fulfilling their intended purpose. Cover Board Pull-through Photo 2 demonstrates a roof in the aftermath of a high-wind event. The weakest link in the system was determined to be the interface between the cover board and fastener plate. The cover board resistance was not sufficient to withstand pull-through, resulting in roof Photo 3: Insulation damage caused by repetitive loading. Photo 4: Substrate damage during a hail event.