To limit the probability of concentrations of stress
at joints in lath, which could lead to the cracking of stucco under
gravity or lateral loads.
This is to limit the
probability of:
precipitation or meltwater ingress, which could lead
to deterioration, which could lead to the structural failure of exterior
walls or elements protected by exterior walls, or
stucco detaching and falling from the building.
This is to limit the probability of harm to persons.