Abstract: A closure element comprising two opposing vertical U-shaped end sections (16,18) with two opposing vertical side pieces (22,24) extending, respectively, between opposing side portions of the end sections. Insulation (26) is packed into the interior of the closure insert (10) to maintain the side pieces (22, 24) in place against the interior surfaces of the side portions of the end sections (16, 18). Otherwise, the end sections (16,18) and the side pieces (22,24) are arranged so that they can move relative to each other to maintain complete closure of the space in which the closure insert (10) is positioned. Foam backed tape (40) is used between the end sections (16,18) and the adjacent building walls/columns to maintain mating contact therebetween.