Tom: It's gonna give you a straight line across the floor. Kevin: Then Nathan installs a new bifold door on "Ask This Old House." ♪♪ Cornetta: Welcome back to Detroit, Mark. Mark: Alright ...

This is how I install a pre-hung door in under 10 minutes. I am sure there are plenty of other great ways to install a pre-hung door, and feel free to drop them down below in the comments. Installing ...