To install a prehung interior door, remove the wood bracing, stand the door and frame in position, and level both sides and the top of the frame with shims. Nail the door frame into place every 18 inches. Install a lockset and trim, and finish the door.Continue Reading
Remove the wood bracing that comes around the door and frame assembly.
Stand the door and frame assembly upright in the rough opening with the door closed.
Place a level vertically along the hinge side of the frame. Insert shims between the frame and the rough opening until the level reads plumb. Hammer a 2 1/2-inch nail through the frame and shims at the height of each hinge. Repeat on the opposite side of the frame. Level the top of the frame in a similar manner, but do not nail it.
Attach the frame to the rough opening with 1 1/2 inch nails every 18 inches all the way around. Sink the nail heads below the surface of the wood with a nailset.
Place a lockset through the pre-drilled openings, and install following the package directions.
Reattach the trim around the door frame.
Apply putty over the nail heads. Let it dry, and sand smooth. Paint or stain the door and frame.