How to Install a Pre-Hung Door
Replacing a door isn't difficult, so you may want to start from scratch by pulling the whole door out and reinstalling a pre-hung door. You don't have to mortise the door and hinges, as you would with an ordinary slab door, and you don't have to make a hole for the doorknob. Here's how to install one:
1. If there's a problem with the door as well as the doorjamb, unfasten the hinges, remove the door and use a pry bar to remove the old jamb.
2. Remove the inner jamb of the new door temporarily, and position the door in place. Use a carpenter's level to ensure that the door is installed evenly and plumb.
3. With the door closed and using wood shims to hold the door and doorjamb plumb and steady as you work, use an air-nailer to nail the door frame to the surrounding studs. Nail directly through the frame and the shims all the way around the frame so that it's secure. Note: Always wear eye protection when working with power tools.
4. Use a utility knife to score and break off the shims all the way around the door.
5. Position the inner jamb back in place, line it up evenly and nail it secure in the same way. Install the nails in the inner jamb on the same plane as the ones used on the outer one so that the inside and outside nails are fastened through the same shim in each case.
6. If you want to paint or stain the door, remove the hinges, take down the door and lay it flat to paint.