What should be considered regarding the width of a sealant joint when selecting a backer?

When selecting a backer for a sealant joint, considering the depth is crucial for ensuring that the sealant performs effectively. The backer rod serves multiple purposes, including controlling the depth of the sealant bead, maintaining proper joint configuration, and allowing for the sealant to bond correctly with the joint surfaces.

By ensuring that the depth is adequately controlled by the backer, it becomes possible to achieve optimum adhesion and elasticity, which are essential for effective movement accommodation in the joint. A well-controlled depth prevents over-compression of the sealant under movement conditions and ensures that the sealant maintains its intended performance characteristics, providing a durable and long-lasting seal.

Furthermore, this approach allows for proper sealant fill, ensuring that it adheres to the sides of the joint but remains flexible enough to accommodate thermal expansion and contraction, moisture movement, and other joint movements. Consequently, controlling the depth by the backer rod is a crucial practice in glazing applications.