If an interior door is damaged, or you’re looking for an inexpensive way to dramatically change the style of your home, learn how to replace doors with new prehung doors. Prehung doors are already attached to a door frame, removing the most labor-intensive part of replacing a door. Slab doors, also known as blank doors, include just the door and not any part of the frame. In general, slab doors are less expensive, but installing a prehung door is much easier for a DIYer. Choose between a prehung or slab door based on your skill level, budget and the condition of your existing door frame.
In this guide, we'll teach you how to remove the old door and how to install an interior door with the use of a prehung door.
Tip: Before you remove or install any doors, check the "handedness" of both the old and new doors. They need to match. To determine the "handedness" of a door, simply open the door. Stand in the doorframe with your back along the hinges. If the hand by the doorknob is your right, it's a right-handed door. If it's by your left, you have a left-handed door.
How to Remove a Door
If you are replacing an interior door with a prehung door, first you must remove the existing door and its frame.
- Remove the hinge pins using a screwdriver and hammer. Then remove the door from the door frame.
- Remove the hinge plates and strike plate from the door frame.
- Loosen the trim with a stiff putty knife.
- Use a pry bar and block of wood to remove the trim without damaging the wall. Take your time so as not to cause any damage. If the trim is in good shape, you can reuse it with a prehung door that has a one-piece jamb. A two-piece jamb door comes with trim attached.
- The head and inside jambs are usually nailed together, so it’s easier to remove them from the opening at the same time.
- Pry the side jambs away from the studs and then pry down the head jamb.
- If you would like to paint, repair or alter the wall in any way, now is the perfect time to do so. Any changes to the wall or door frame should be made before installing a prehung door. Once again, take care not to damage the wall during this step in the process.
Position the Prehung Door
Once you have removed the old door and prepared the doorway, you can start on the first step in how to install an interior door.
- Slide the prehung door into the rough opening.
- Put the door in the opening and slide it until the jamb is flush with the wall.
- Double check to be sure the door opens in the desired location and direction.
Tip: Prehung doors are often heavy and hard to maneuver alone. A helper makes it easier to lift and hang the door.
- Use a level to check that the door is straight. Add shims to adjust the level and ensure the jamb is plumb.
- The door frame should be slightly smaller than the opening it fits to allow for adjustments. Slip shims under the side jamb until the head jamb is level.
- Shim between the side jambs and the studs to fill in the spaces between them.
- On the hinge side, start with the bottom and top of the jamb. Shim between the hinges and studs, positioning the shims so that about half the shim is above the hinge, which will help you later when nailing.
- On the latch side, shim at roughly the same places and at latch level.
- Check the level of the door again.
Nail Door Frame to Studs
- Drive two #8 finishing nails through the frame, through the shims and into the studs.
- Drive two nails through each shim about an inch from each edge of the jamb, with one about a 1/2-inch above the other.
- Before driving the nails home, open and close the door and make any necessary adjustments.
- When you’re satisfied with the way it performs, drive and set the nails.
Install Door Trim
- Nail the trim to the jamb and studs.
- Drive #6 finishing nails through the trim and into the studs behind the wall, spacing the nails about 16 inches apart.
- Trim any exposed shims by scoring them with a knife and then breaking along the line.
- Cut and install the trim on the second side of the door in the same manner as the first side.
Attach Hardware and Accessories
- Once the door is hung, attach the backplates and door knobs. Make sure not to screw the knobs on too tightly.
- Add the lockset and strike plate.
Tip: Prehung doors typically come with attached hinges and pre-cut places for the door knob and strike plate. However, you’ll have to purchase the door knob, lockset and strike plate separately.
Now that you know how to install an interior door, you can replace old, damaged doors and make quick updates to your home. If you’d rather leave the job to a professional or want a slab door installed, consider contacting our local experts to do the door installation for you.