30 l ROOFINGBC l WINTER 2018 FEATURE C over boards are commonly used in commercial roofing to add strength and protection to a roof assembly. They are a rigid board in a compact roof assembly that enhances resiliency and durability. Cover boards are installed below the membrane and above the insulation to minimize the deterioration of other materials during the service life of the roof. Cover boards have become increas- ingly important as a result of climate adaptation initiatives to ensure that roofs are increasing their durability in response to changing weather events. They are also commonly used as platforms for rooftop add-ons, such as photovoltaics and green roofs, which result in increased foot traffic and additional stresses on the roof system. Therefore, cover boards have a major role in protecting the roof assembly from damage and as a result, must possess critical properties to fulfil their function. Roof failures due to high wind events can be attributed to the cover board interface as the weakest link (Figure 1). The observed field failures have led to BY DOMINIQUE LEFEBVRE AND BAS BASKARAN, NATIONAL RESEARCH COUNCIL OF CANADA Figure 1: Failure of roof assemblies due to a lack of peel resistance between interfaces. Section head: FEATURE Head: North American Consortium Advancing Cover Board Requirements Deck: With the Inclusion of Interface Evaluation By Dominique Lefebvre and Bas Baskaran, National Research Council of Canada Cover boards are commonly used in commercial roofing to add strength and protection to a roof assembly. They are a rigid board in a compact roof assembly that enhances resiliency and durability. Cover boards are installed below the membrane and above the insulation to minimize the deterioration of other materials during the service life of the roof. Cover boards have become increasingly important as a result of climate adaptation initiatives to ensure that roofs are increasing their durability in response to changing weather events. They are also commonly used as platforms for rooftop add-ons, such as photovoltaics and green roofs, which result in increased foot traffic and additional stresses on the roof system. Therefore, cover boards have a major role in protecting the roof assembly from damage and as a result, must possess critical properties to fulfil their function. Roof failures due to high wind events can be attributed to the cover board interface as the weakest link (Figure 1). The observed field failures have led to the in-depth investigation of the cover board properties and performance. Figure 1: Failure of roof assemblies due to a lack of peel resistance between interfaces. Peeled Cover Board Peeled Membrane the in-depth investigation of the cover board properties and performance. Currently, North American manu- facturers produce various types of cover boards which can be categorized depending on the material composition as: • asphaltic-based boards, • insulation-based boards, • cement-based boards, • gypsum-based boards, • fibre-based boards, and • recycle-based boards. Due to differences in material proper- ties, the cover board performance varies when incorporated into a roof assembly. Some of the board types already have individual standard specifications, while others do not. The existing standards differ from one another in the proper- ties specified as well as in the minimum performance requirements. This leads to the fundamental question of what prop- erties a cover board must have, regardless of its type, to fulfil its intended function in the roof assembly. The National Research Council of Canada (NRCC) assembled a consor- tium group to work with the North American roofing industry to develop the requirements for cover boards. Sixteen North American participants, listed in the acknowledgements, joined NRCC’s consortium group, including manufacturers, industry associations and contractor associations. The objective of the project is “to develop a harmonized standard specifying the performance criteria for the use of cover boards in commercial roofing.” The R&D outcomes of the experimental program under execution will be used for the develop- ment of the consensus-based standard. The consortium identified two types of investigations that are essential for cover boards: material and interface testing, outlined in Figure 2. Material testing is used to obtain the properties of the cover board to establish its require- ments as a standalone component, such as dimensional stability and compres- sive strength. Interface evaluation (IE), which is the intermediate testing between NORTH AMERICAN CONSORTIUM ADVANCING COVER BOARD REQUIREMENTS With the Inclusion of Interface Evaluation