each member is a standard beam shape that is used in construction of screen enclosures and extruded through a die process to various lengths first member 130 and second member 120 are assembled in the field to form the new structural beam 100 the materials used to make beam 100 are the same aluminum alloys that are used in the construction of aluminum screen enclosures the wall thickness of first member 130 and second member 120 will vary between each size change and are dependant on code requirements to meet deflection criteria in the local and state building codes referring now to fig2 and fig3 a cross section of the beam 100 is shown including the coupling of the flanges a longitudinal slot 125 on top flange 150 and longitudinal slot 127 on bottom flange of second member 120 show where screws are used to secure first member 130 and second member 120 together an architectural groove 129 is provided on bottom flange of second member 120 and an architectural groove 132 is provided on the top flange of first member 130 that mirrors the groove that is formed when the top flanges and bottom flanges are assembled together a rigid webbing 135 interconnects upper flange 150 and lower flange 140 in cross sectional view the first member is generally c shaped a longitudinal channel 142.