Traditionally, precast had been designed as face seal assemblies where the weather tightness relies on water repellence treatment of the precast panels and on the detailing of the panel joints, such as binary sealant joints.  More recent designs have attempted to incorporate rainscreen principles in the design of precast wall assemblies .  In a typical rainscreen construction, the back up wall is installed first and then weatherproofed prior to the cladding installation.  Such sequence happens to be challenging or impractical when the precast panels are designed as curtain wall to be hung on the building structure. 

Claude has been involved in projects which addressed the need to install the precast panels first while incorporating a drainage path in the wall assembly.  The drainage path was achieved by attaching a drain mat on the back side of the precast panels.  He will present case studies and lessons learned from three projects recently completed in Vancouver, BC and in Portland, OR.