Expansion/Control Joints: The Most Controversial Metal Lath Accessory
No matter how many opinions there are, ASTM C1063 as cited in the new International Building Code and most model building codes, requires the installation of control/expansion joints.
ASTM C1063 states, "Control joints shall be formed by using a single prefabricated member or fabricated by installing casing beads back to back with a flexible barrier membrane behind the casing beads. The separation spacing shall be not less than 1/8 inch or as required by anticipated thermal exposure range (per author and to accommodate stucco shrinkage)." It goes on to state that it has to conform to the previous section that states the following: "Lath shall not be continuous through control joints but shall be stopped and tied at each side."