Expansion Joints versus Control Joints
Control Joints (CJ) are 1-piece joints designed to relieve stress and minimize cracking; they accommodate initial stucco shrinkage and minor thermal movement. The Control Joints are required to form membrane panels no larger than 100 sq.ft for ceilings and 144 sq. ft. for walls. On the other hand, Expansion Joints are 2-piece joints designed to accommodate a full break through the structure across dissimilar surfaces or to deal with some minor structural movement.