Cutting a doorway into a center support wall in the basement (cement block)
I would like to cut a 4 ft hole into my basements center support wall. This wall is cement block, and spans 40 ft down the center of my house. Above it are perpendicular floor beams that are 25 ft long. There is one doorway already cut towards the center of the wall, and that is 4 ft wide. I would like to cut another doorway closer to one of the sides, so I can access the other half of the basement easier. Will I need to put in floor jacks or a header of some kind? What is the best way to knock this block out? Are there any dangers to be aware of?
Thank You!
DC