Board for panels and similar covering material

Claim 1

A BUILDING BOARD COMPRISING A SUBSTANTIALLY RECTANGULAR FOUNDATION BOARD MEMBER HAVING UPPER, LOWER AND SIDE SURFACES, EACH SIDE SURFACE HAVING A GROOVE DISPOSED THEREIN EXTENDING TOWARD THE CENTER PORTION OF SAID BOARD MEMBER AND BEING SUBSTANTIALLY PARALLEL TO THE UPPER AND LOWER SURFACES, SAID UPPER SURFACE BEING FORMED BY TWO SURFACES INTERSECTING EACH OTHER AT AN ANGLE ALONG A LINE PARALLEL WITH THE SIDE SURFACES, AND A COVERING MATERIAL OF SUBSTANTIALLY RIGID MATERIAL BEING APPLIED TO SAID UPPER SURFACE, SAID COVERING MATERIAL HAVING LONGITUDINAL EDGES THEREOF DISPOSED WITHIN THE GROOVE OF SAID SIDE SURFACES, THE COVERING MATERIAL BEING BENT ALONG ANOTHER LINE CONTAINED IN A PLANE EXTENDING THROUGH SAID FIRST-MENTIONED LINE AND WHICH IS PARALLEL WITH SAID SIDE SURFACES TO FORM TWO SURFACES INTERSECTING ALONG SAID OTHER LINE IN THE SAME MANNER AS THE TWO SURFACES OF SAID UPPER SURFACE, SAID OTHER LINE BEING SPACED AWAY FROM SAID FIRST LINE SO THAT A SPACE IS PROVIDED BETWEEN THE UPPER SURFACE AND THE INNER SURFACE OF SAID COVERING MATERIAL WHEREBY WHEN THE BOARD MEMBER EXPANDS OR CONTRACTS THE SPACE BETWEEN THE LINES CHANGES.