These directions summarize some supplies and steps we have found helpful when working with doors. This information is offered for use at your own discretion, and it may or may not be applicable to your specific project. Please consult a professional for more detailed advice regarding your project. 



-Jamb – the frame to which a door is secured

-Slab – the actual door itself, without the frame or hardware

-Panels – decorative squares or sections of the door

-Hinge – a metal piece of hardware that attaches to the door and jamb and allows the door to swing open

-Rail – horizontal members of the door structure, found at the top and bottom of the door

-Stile – vertical members of the door structure, found on the hinge- and handle-side of the door

-Casing – the external decorative structure that attaches to the wall, frames the door, and covers up any unsightly edges

-Sill or threshold – the bottom part of a prehung door that sits on the ground, touching the subsill, in exterior doors

-Subsill – the floor in door frame, where the door sill will rest

-Weather Stripping – long rubber pieces that go around the door and help seal it from water and air

-Bore – the hole where a door handle will go

-Mortise – the holes in the door that hold hardware, such as hinges or latches

-Lites– the glass set into a doorframe that lets in light, often found on the side or top of the door





-Tape measure, for sizing up the door and finding a good replacement

-Sawzall, for cutting out the current doorjamb

-Flatbar, for prying casing loose

-Flathead screwdriver, for knocking the hinge pins out of the original door

-Hammer, for knocking the hinge pins out of the original door

-Utility knife, for cutting around the casing and for cutting off the protruding parts of the shims

-Pliers or nail nipper, for removing nails from the rough opening of the door

-Level, to check if the door and doorjamb are plumb

-Shims, to hold the jamb in place and make the jamb plumb (These can be cedar shims specifically made for installing doors and windows, or you can use any thin wood or paper material.)

-Drill, to create a hole for the nails (Use a bit size slightly smaller than the nail)

-Finish nails, 8d to 16d, depending on thickness of jamb, to hold the doorjamb in place

-Saw, for cutting your replacement doorjamb slightly if the ground is uneven



  1. Determine whether or not to replace the jamb—not just the door slab
    1. Is the jamb warped, rotten or vastly uneven? Does it bow and pucker? If so, the jamb must be replaced
    2. If you want the door and jamb to match up very closely, it is often better to have the replacement door matched to a jamb before installing, rather than replacing the door only and trying to match it up to the old jamb. If the replacement door is nearly identical to the old one, matching up a new door to the old jamb may not be too hard
    3. Can you handle a door with a jamb? Though installing a pre-hung door is often simpler than installing a door slab into an old jamb already in place, installing a pre-hung door is definitely more of a challenge to physically handle. The job is best done with two people
  2. Measure the current door and doorjamb
    1. Measure the height on both the knob and hinge side of the door
    2. Measure the width at both the top and bottom of the door
    3. Measure the thickness of the door, and depth of the door jamb
    4. Most interior doors are usually about 1 3/8” thick, and exterior doors are usually 1 3/4” thick. Standard heights run in 2” increments.
  3. Remove the casing or trim around the current door
    1. Take a utility knife around the edges of the casing, if it is painted or caulked. In addition to helping release the casing, this will also prevent tears in the paint or wallpaper
    2. Use a flatbar to pry up the casing. Try to do it as gently as possible, so you can reuse the casing later
  4. Measure the rough opening. The rough opening is the opening left with the door and jamb removed. You can see this if you remove the casing
    1. Measure the height of the rough opening on the knob and hinge side of the doorjamb
    2. Measure the width of the rough opening at both the top and bottom of the doorjamb
    3. The rough opening is usually 2” bigger than the door in width and height
    4. The jamb should not fit too snugly inside the rough opening. There should be about 1/2” of room on each side. However, more space is fine, so long as you have plenty of shims and the right casing to cover it up
  5. Finally, determine the swing of the door, and note where the handle lies. Take note of how this fits into the room or hallway
    1. Each business has a different way to determine the swing of the door. When in doubt, describe the way you determined the door swing to a customer service rep
    2. Below is Second Use’s criteria for determining door swing:
      1. Go to the push side of the door
      2. From there, put your back to the hinge
      3. Extend your arms
      4. If the right hand is closer to the door knob, you have a right hand door, and vice versa
    3. You may choose a replacement pre-hung door with a different swing or handle. This is fine, so long as it fits your space
  6. For the simplest door replacement procedure, find a pre-hung door the same size as your original one
    1. Mentioned earlier, it’s possible to select a slightly smaller pre-hung door than the original, if you have casing to cover up the gaps you will create
    2. However, do not select a larger pre-hung door than the original. Too tight of a fit in the rough opening may ruin the door and its ability to swing and latch properly.
  7. After you’ve purchased your replacement pre-hung door, you can first remove the old door from its jamb, if you prefer
    1. Knock the hinge pins out of the hinges with a flat bar or flathead screwdriver and hammer
    2. This job is best done with two people—one holding the door, and the other working on the hinge pins.
    3. Once the door is out, set it aside while you remove the jamb
  8. Assuming the casing is already removed from both sides of the old doorjamb, you are now ready to remove the doorjamb. With a sawzall, cut around the doorjamb to remove it from the wall
    1. You will be cutting through the finishing nails and shims used to hold the jamb in place
    2. Hold the sawzall firmly, as it will want to bounce around
    3. Be careful not to let the saw blade hit the floor. You can cut upward from the bottom of the jamb to avoid hitting the floor
  9. Push the doorjamb out of the wall and set it aside
    1. If flooring was installed after the doorjamb was put in place, the jamb may not have room to come out easily.  It may be possible to bend the long parts of the jamb enough to get it loose. If necessary, you can cut the legs of the jamb shorter with a saw, so you can pull it free
  10. With a pair of pliers or nail nippers, pull out the remains of the finishing nails in the doorjamb and wall
  11. Double check your measurements
    1. Ensure your rough opening is the same height as you had planned for
    2. Check to see if the floor is level. If it is not, you may need to cut one side of your doorjamb slightly with a saw
  12. Lean the door into its spot and position it so the jamb lines up with the baseboards
    1. Remember to pay attention to which way you want the door to swing
  13. Using a level, make the door plumb (exactly vertical)
    1. Also eyeball the gaps between the doorjamb and the rough opening. Do the gaps look approximately even on all sides?
  14. Place a shim just above the top hinge, in between the jamb and rough opening. Then place a shim on the other side (horizontally) of the door jamb, ensuring the structure will stay level
    1. The biggest challenge in installing a pre-hung door is making the door plumb and level. Take your time and ensure the job is done right
    2. Use a hammer to lodge the shims in place
    3. You can continue to adjust the door slightly
  15. Once the door is secure, try opening and closing it. Does it look as though it swings correctly? If it looks good, leave the door open
  16. Drill a small hole through both the jamb and shims
  17. Secure the door by hammering finish nails through the shims and jamb into the wall frame (more specifically the jack stud), leaving the nail protruding about 1”, in case you need to readjust the door
  18. Continue these steps, working your way down the door
    1. Do the hinge side first, then go across to the other side (horizontally) of the door
    2. Make sure the door is plumb each time you insert a shim and add the nail. Remember to check both sides of the door (inside and outside a room). Also, make sure the door will open and close at each step.
    3. As a general rule, place shims at three locations on each side of the door and at each corner on the top
    4. Also consider shimming right above and below the door latch. This means the handle-side of the door will have four sets of shims
    5. For the top, do the handle-side first, then move to the other side of the door (horizontally)
    6. Do not over-shim the door. Too many shims will cause the jamb to bow, and the door will not shut properly
  19. If the door is plumb, hammer the nails down the rest of the way, flush with the surface of the jamb.
  20. Cut off any protrusion from the shims, flush with the wall, with a utility knife
  21. Install casing around both sides of the doorjamb, for a finished look
    1. You may be able to use the old casing, if the dimensions of the new door are close enough to those of the old one. Otherwise, install replacement casing