Abstract: A frame for use as a portion of an external wall of a building includes an upper horizontal C-shaped section channel member and first and second vertical C-shaped section channel members. Each C-shaped section channel member includes a pair of spaced flanges joined by a web, with end portions of the flanges opposite the web being bent inwardly toward each other to define a mouth. The C-shaped section channel members are rigidly assembled with the first vertical member extending vertically downwardly from a first end of the horizontal member and with the mouth of the first vertical member facing inwardly of the frame, with the second vertical member extending vertically downwardly from the horizontal member at a position spaced longitudinally thereof from the first vertical member and with the mouth of the second vertical member facing outwardly of the frame, and with the mouth of the horizontal member facing upwardly.