Before installing the pre-hung door, remove the damaged door and doorjamb. Then pull the pins beginner lockset from the hinges of the pre-hung door to remove the door. Install the new doorjamb and perform any required adjustments with wood shims. The two sides of the doorjamb should be vertical, the top should be level, and the opening should allow clearance for the door to shut. Lift up the door to join the hinge halves together. Then reinsert the pin. If the door closes properly, install the locks if not already done.
If you need to make large adjustments when installing the new door, then it may be easier to use separate pieces rather than a pre-hung door.
Repairing a damaged door — If only the recessed panels of a door are damaged, they can be replaced or covered over. If the main framework of a door is damaged, then the door usually has to be replaced.
For the most attractive appearance, replace the damaged panel with a matching panel prepared by a woodwork shop.
A door panel normally is held in place by trim around the outside edges of the panel on both sides of the door. Carefully remove this trim from one side of the door. Then remove the damaged panel and insert the replacement panel. Reattach the trim around the replacement panel.
Replacing a damaged door
If the door cannot be repaired, you need to confer with the customer about the type of door to use for a replacement. If the desired type of door is not available locally, the customer may decide to use whatever is available.
When determining the height for the door, you should consider any new or existing threshold and door sweep to be attached at the bottom of the door.