Prehung Interior Door Installation

Measure the rough opening in which you want to install the door. Ensure that your pre-hung door is properly sized to fit in this opening and that it is handed correctly. A door must be hung in the jamb to open into a room in a specific direction and this will determine the side on which the hinges are set. Check the square of the opening to determine in advance how much shimming is going to be necessary.

Trim the legs of the jamb to adjust the finished height of the door. An interior door should have about ½-inch of airspace at the bottom of the door. Pre-hung doors usually ship with legs that are longer than necessary so that you can adjust the height for different flooring materials, such as tile, wood and different piles of carpeting. If the floor in the rough opening is not level, you also can trim the legs to different lengths to level the door in the opening.

Place the door assembly in the rough opening, and make sure that the wood of the jamb is aligned with the drywall on both sides of the opening.

Level the door vertically. On the hinge side of the door, place shims between the jamb and the door framing until the level indicates plumb. Use 10-penny finishing nails to secure the door jamb to the rough jamb. Drive the nails through the shims, leaving about ½-inch of the nail exposed in case adjustments are needed. When the door installation is complete, set the nails.

Square the striker side of the jamb. Following the same process as above, use shims to create an even space between the edge of the door and the jamb. Nail the door in place through the shims. Be careful not to shim this side of the door so much that it creates binding on the opposite side.

Check the spacing on all sides of the door to ensure that it is even. Test the swing of the door to make sure that it does not bind at any point in its movement. When you are satisfied with the fit and movement of the door, set the nails and trim the excess material from the shims.