I have a commercial space I am working on and would like to open up the wall between two rooms its a single story building, flat roof, concrete flooring. one room is 400 sq ft and the other is 600sq ft. I just want to open it up to the exterior wall one one side and where the thermostat sits on the other just before the hallway entrance. I have removed most of the drywall seen in the picture so you can get a good idea of all the studs i'll be removing. It seems there use to be two windows in this wall but then was just converted into a wall with a center opening. There is an 18inch beam under the joists running across the whole building to both exterior walls. Thanks in advance for the help!
I would definitely assume the wall is supporting that beam. Get a structural engineer's advice to be sure, and to find out what your options might be. Solutions often exist, but may not be DIYable... and this is emphatically not something you want to risk getting wrong.
For comparison: My contractor was able to open a 15-foot-wide passageway through a central loadbearing wall, but we needed to install a heavy (4x12?) Parallam beam to absorb the load, strong columns at each end to transfer the load downward, and at the non-foundation end a steel C-beam was sistered to an existing joist to transfer load to foundation and main beam.