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How to Install a Prehung Exterior Door

A new front door is a great way to spruce up your home’s appearance and improve safety. Most people choose prehung exterior doors because they are easier to install than hanging a door yourself. Learning how to install a prehung exterior door will require you to fit it in place and secure it to your home. This is a fairly simple process because a prehung door has the door inside a frame that you fit into the rough opening. All of the hinges are already connected, and the holes for other door hardware are predrilled and aligned. If you live in the Mid-Atlantic and would like help with your front door upgrade, request a quote from the experts at PJ Fitzpatrick today!

Step by Step How to Install a Prehung Exterior Door

  1. Gently pry off interior trim to expose the edges of the door frame.
  2. Measure the frame opening’s width and height.
  3. Measure the depth of the door jamb.
  4. Buy a new prehung exterior door that is 1/2 inch shorter than the height and 3/4 inch narrower in width.
  5. Confirm that the door is the correct size when you pick it up and that it’s undamaged.
  6. Cut through the caulk around the exterior trim.
  7. Pry off the trim.
  8. Working with a nail set and hammer, drive the hinge pins up and out.
  9. Lift the old door off its hinges.
  10. Before you continue to learn how to install a prehung exterior door you will need to take the strike plate off the old door frame.
  11. Fit the blade of a reciprocating saw between the door frame and the rough opening.
  12. Saw through all screws and nails currently securing the old door frame.
  13. Starting at the top, bang the newly released frame out with a mallet or pry bar. It should tilt out.
  14. Sealant beneath the sill may require you to push and pry before the door comes completely away.
  15. Use a level and carpenter’s square to see if the opening is square and plumb.
  16. Make corrections to the opening, if necessary, by attaching shims with screws.
  17. Your new prehung exterior door should include a sill pan. If it does not have one, install a sill pan kit.
  18. If you need to re-install a doorbell, now is the time to drill the hole for its wires through the door frame.
  19. Load the caulk gun and run beads of caulk along the back of the door’s brickmould.
  20. Lift the bottom of the door into the sill area.
  21. Tilt the door into the opening.
  22. Slide the doorbell wires through the hole.
  23. Insert shims between the door frame and rough opening. Place one at the top of each hinge screw, around the latch, and the top and bottom of the latch side.
  24. The shims are important for installing a prehung exterior door because they keep the frame firm and straight.
  25. Confirm that the door is plumb within the opening.
  26. Make corrections with shims as necessary.
  27. Drill pilot holes at the hinge areas and then drive the screws halfway in.
  28. Before driving screws on the latch side, shut the door.
  29. Examine the weatherstripping to see if it is touching equally in all areas.
  30. To fix any problems with the weatherstripping, adjust the latch side of the door.
  31. Drill pilot holes where you have shimmed the latch side.
  32. Drive screws halfway in on the latch side.
  33. Check the frame for plumb. If you need to make corrections, use more shims. Drive all screws in completely except for the one at the latch plate.
  34. Place shims behind the strike plate and middle screw.
  35. Attach the strike plate and drive in the final screw.
  36. If the door seems too tight or loose along the sill, adjust the sill plate up or down. There will be screws on it for tightening or loosening its position.
  37. Caulk around all edges of the door and sill.
  38. Install the doorknob and locks.
  39. With a utility knife or oscillating saw, trim off the edges of shims flush with the frame.
  40. Put the interior trim back on.

Tools & Materials

  • Work gloves
  • Safety glasses
  • Small pry bar
  • Tape measure
  • Utility knife
  • Screwdrivers
  • Nail set
  • Power drill
  • Rubber mallet
  • Carpenter's square
  • Level
  • Oscillating saw
  • Reciprocating saw
  • Caulk gun
  • Hammer

New Doors Installed by PJ Fitzpatrick

When you are learning how to install a prehung exterior door, you can always benefit from an extra set of hands. If you’d prefer to assign this multistep DIY job to professionals, PJ Fitzpatrick installs entry doors, sliding doors, and storm doors throughout the Mid-Atlantic. We supply doors from a variety of reputable door manufacturers. Contact us today about your exterior door replacement needs.

Need help with this project?

We have trained professionals that can help. Contact us today. 1-877-246-4354

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