Wind uplift is a significant factor that can affect the integrity of roofing systems. This following outlines CRCA and its members commitment to addressing wind uplift concerns and the responsibilities of both the roofing contractors and design community to ensure the structural and functional integrity of roofing systems.
WHEREAS, The Canadian Roofing Contractors Association (CRCA) supports the design and installation of roofing systems that will perform and withstand adverse weather conditions.
WHEREAS, the contractor needs to provide a proper bid associated with a project, tender documents provide by designers must contain all necessary components to meet current code requirements.
WHEREAS, designers should be providing the required wind loads and a roof system design that meet or exceed required loads as per building code requirements at the design stage of a project.
WHEREAS, the responsibilities, including proper design drawings and specifications, associated with these calculations rest with the design authority.
WHEREAS, roofing contractors are responsible for understanding the design specifications including the wind uplift design requirements. They must ensure that all roofing systems and installation methods are consistent with the approved design.
WHEREAS, CRCA issued an advisory bulletin in June 2018 titled
Roofing Contractors and Designers Responsibility detailing the different responsibilities that arise on a roofing project.
It is the CRCA policy that,
“Roofing contractors should not bear the responsibility of determining wind loads and the proper roof system design to meet or exceed those wind loads.” What is CSA A123.21 wind uplift standard?
CSA A123.21 Standard test method for the dynamic wind uplift resistance of membrane roofing systems is a standard to ensure that roofing systems are tested for wind resistance. The standard describes a method of the wind uplift testing of roofing systems that must be completed by an accredited laboratory.
The standard was developed through the Special Interest Group on Dynamic Evaluation of Roofing Systems (SIGDERS) research program. SIGDERS is a consortium of members of the North American roofing community that was created as a means of evaluating the effect of dynamic wind loads on roofing systems.
Wind uplift and code requirements
CSA A123.21 was first introduced in the National Model Building Code in 2015 and focused the attention of the design community on wind uplift resistance of roof systems.