Bargeboard finials are a multi-purpose decorative piece used to cover the joint between the two bargeboards at the apex of the roof.The bargeboard system must expand and contract correctly dependant on the temperature. For any PVC fascia installation, it is recommended to glue one side of the finial to the board and seal the other side with low modulus silicon , which allows for movement within the joint.Freefoamand#039;s replacement fascia bargeboard finial is 335mm in length.