To limit the probability of butted ends jamming upon linear expansion due to an increase in moisture content from exposure to precipitation, which could lead to buckling, which could lead to the displacement of cladding, trim and flashing, opening of joints or failure of caulking, which could lead to 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, which could lead to harm to persons.