Patent ID: 7257932

Claim:
A light weight building material having a length, a width, and a height, the building material comprising: first and second side sections, a top section, and a bottom section, the sections being formed as a rectangular single elongated metal sheet, the first and second side sections extending longitudinally along the length of the building material and laterally along the height of the building material, the first and second side sections being generally parallel to the other, and the first and second side sections including a plurality of corrugations extending in a direction traverse to the length of the building material, the plurality of corrugations disposed on only the first and second side sections, the top section extending longitudinally along the length of the building material and laterally along the width of the building material, the bottom section defining a first and second bottom portion extending longitudinally along the length of the building material, the first bottom portion having a width substantially equal to a width of the second bottom portion, and the bottom section having a rolled interlocking joint including at least four layers extending longitudinally along the length of the building material, the rolled interlocking joint including a first generally U-shaped portion formed from the first bottom portion and a second generally U-shaped portion formed from the second bottom portion, each U-shaped portion forming two of the four layers of the rolled interlocking joint, each U-shaped portion being configured to interlock with the other, and each U-shaped portion having a major surface extending laterally along the width of the building material, and the major surface of each U-shaped portion having a lateral width that is at least two times greater than a thickness of the interlocking joint in a direction perpendicular to the lateral width.