Bargeboard finials are a more decorative way of covering the joint between the two bargeboards at the apex of the roof.To enable the bargeboard system to expand and contract correctly in a different range of temperatures, one side of the finial should be glued to the board and the other side should be sealed with low modulus silicon, which allows movement within the joint.This rule should be always applied to any corner or joint cover on any PVC fascia installation.