Multiple void layer synthetic resin panels

A light-transmissive panel is provided having a unitary synthetic resin skeletal structure having a continuous length. The panel may be used alone or in a multiple panel structure. The panel structure has first and second exterior plates and at least two spaced apart interior plates located within a space between the first and second plates such that the first, second and interior plates lie in planes generally parallel to each other along the length of the structure and a space is created between each pair of plates. The first, second and interior plates are interconnected by a plurality of walls extending in a direction perpendicular to the planes of the plates forming a plurality of continuous cellular voids extending parallel to the length of the structure. In a multiple panel structure in which two or more juxtaposed panels are joined together by a connector, the first plate of each panel in the structure has two length-wise extending recessed channels. The connector is adapted to releasably engage the channels.