Drywall Framing System
#40 Expansion Joint is a two-piece, slip joint that finishes butt ends of adjacent panels in wide or tall walls and ceilings to allow for multi-directional movement. Panels are attached to parallel studs through the expansion joint flanges, enabling the finished surface to expand or contract naturally without cracking. #40 is ideal for joining dissimilar wall types such as wood framing to CMU and at construction joints. Adjustable expansion opening or reveal is 1/4" to 5/8". Additional weather shields should be installed behind the joint to enhance the weather resistance of this system.
Suggestions for installation precautions when installing two-piece expansion joints and double casing beads used as double expansion joints: ASTM C1063 requires that double casing beads used as a movement joint “with a flexible barrier membrane behind the casing beads.” It is Clark-Dietrich’s opinion that all two-piece joints whether made from double casing beads or as a manufactured two-piece joint should be installed with the flexible peel and stick membrane behind the joint and it is further recommended that they be filled with backer rod and a highly elastic top quality sealant.