Hello. I can help. Can I get back to you in a couple hours?
What will we the span of the beam between posts? What is the joist length on each side of the beam? Will it support the attic joists only and no floors or the roof?
Thank you for the additional information.
Is this a flat roof or a gabled roof?
What is the city in Minnesota so I can determine the snow loading?
Thank you. I'm sizing the beam now
You would need 4 - 2x12 to span 11' between posts supporting the 60 psf snow load.
A 60 PDF snow load is heavy and dimension lumber is not strong
Do you have any other questions for me on this topic? If you could rate my answer, I would appreciate it.