The parapet

This is another interesting location of the same building. The parapet above the sandwich knee wall hits the masonry wall corner. The masonry wall extends down beyond, creating a convex corner. The right side of the wall has been sheathed with waterproofing EPDM membrane.  The metal parapet cap has no control joints at its length. Its end cap has perforated the membrane at the time of installation.  As the temperature changes within its usual annual and daily range this end of parapet would travel along approximately 1 1/2" and simultaneously widen the existing membrane perforation.  The screws, which fasten the lower edge of parapet, would create elliptical slots, widened by the same thermal movements. The visible vertical joint between brick veneer and the waterproofing membrane sheathed wall is filled with a stiff mortar, which would crack and spall, because of the thermal movement and brick expansion.