This Architectural Drawing is AutoCAD 2d drawing of Roof Beam Construction Details in AutoCAD, dwg file. Beams may be of wood, steel or other metals, reinforced or prestressed concrete, plastics, and even brickwork with steel rods in the bond between bricks. For weight reduction, beams of metal are formed as an I or other shape having a thin vertical web and thicker horizontal flanges where most of the strain appears.