How to Replace a Prehung Door

Prehung doors come preassembled with the door jambs, the door, and all of the hardware intact. These doors can be used for interior installation as well as for exterior as long as the door is rated for this type of use. When installing prehung doors, there is no need to remove the door before installation, which makes installing a prehung door a quick and easy task. Prehung doors are easy to find. Most do-it-yourself and home improvement stores will have them in stock.

Things You'll Need

• Hammer
• 4-foot level
• Straight edge
• Reciprocating saw
• Finish nailer
• Shims

Instructions

1. Place the ripping chisel behind both the interior and exterior trim of the door and pry it off. Use a hammer to tap chisel behind the trim if needed. Nails will either come off with the trim or pull right through the wood.

2. Place the blade of the reciprocating saw between the door jamb and the trimmer stud and cut through the nails around the door. Cut through any shims with the reciprocating saw and remove them as well. Remove the entire door and frame from the opening.

3. Clean out the door opening. There may be shims or nails that either need be cut flush to the wood or hammered back so that new door can be installed with no obstacles.

4. Adjust a pair of shims to one-half inch thickness towards the top hinge side of the door opening. Nail them to the trimmer stud.

5. Set a pair of shims at the bottom hinge side of the trimmer stud. Using a level with a straight edge, adjust the bottom pair of shims until they are plumb with the top pair of shims. Nail the shims to the trimmer stud.

6. Position the prehung door frame in the opening. Drive nails through the door jamb, shims and into the trimmer stud.

7. Check clearance between the bottom of head jamb and top of door. If the lock side of head jamb is too high, it may be corrected by using a flat pry bar to force up hinge side of jamb. If the lock side of head jamb is too low, it may be corrected by raising the lock side jamb before it is nailed. To raise the jamb on either side, place the flat pry bar under the bottom of the jamb and step on the other end of the pry bar to force up the jamb to desired position.

8. Shim and adjust the entire jamb to its proper clearance around door. Drive nails through the jamb and the shims into trimmer studs. Be sure to insert shims behind hinges and lock strike. Once the door shims and door are nailed, replace the trim on both sides.

Tips & Warnings

• Wear appropriate safety gear when using power tools. They can cause serious injury if mishandled.

Resources

• Home Depot
• Lowes
• Prehung door replacement tips