How do I hang a prehung door?
A prehung door is usually hung centered in a wall. The molding that forms the sides of the prehung door, called jambs, are generally 4 1/2 inches wide, the thickness of a 2x4 (actually about 1 1/2 x 3 1/2 inches) stud plus 2 sheets of 1/2 inch drywall.

The door does swing to one side, and you can turn it either way. You need to decide which room you want the door to open into and which side you want the hinges on in that room. Prehung doors come in left hinged and right hinged versions.

If you are cutting a hole in the wall for the door (as opposed to putting it in an existing opening), you need to frame out the opening



The prehung door then fits within this frame. All illustrated boards are 2x4 studs except the header which is usually either 2x4 or 2x6 depending on the width of the door.