How to install a prehung wood door

Check the rough opening. Place a 4-foot level on the floor in the doorway.

Shim the trimmers. On the hinge jamb, measure from the bottom of the jamb to the center of each hinge.

Fit door into opening. Lift the door into the rough opening and push the hinge jamb tight against the shims tacked to the trimmers.

Adjust the gap between the door. Check the horizontal gap, or "reveal," between the top of the door and the head jamb.

Anchor the jamb. Slip a pair of shims between main jamb on the latch side and the trimmer, near the top of the door opening.

Replace hinge screw. On the hinge jamb, remove the center screw from the top hinge leaf and replace it with a screw that's long enough to penetrate the trimmer.

Attach the split jamb. Starting at the bottom, gently push the edge of the split jamb into the groove in the main jamb.

Mount the latch hardware. Fasten the strike plate to the mortise in the latch jamb using the screws provided.