How much weight can a 2x12 support?

A double ply beam can span in feet if there is no overhang beyond the beam.A double 2x12 beam can span 12 feet.

How much weight can a 2x4 support?If the load is square and there is no wind, the average 8 feet 2x4 could handle around 1,000 pounds vertically.It's wise not to push the material up to its limit, use a brace and secure the 2x4s whenever you need them.