Do It! How to Remove and Replace Exterior Door Casing

Exterior door casings that are exposed to the elements often rot at the bottom due to the absorption of rainwater through the wood’s end grain.

To prevent rot when replacing outside door casings, such as brick mold, use casing made from plastic composite material. If wood casing is used:

    • Apply wood preservative to the end grain of the casing.
    • Allow the wood preservative to dry.
  • Prime and paint the end grain of the casing before installing the molding to prevent water absorption.

Steps in Replacing Door Casing

To replace door casing, such as brick mold:

    1. Use a utility knife to cut through the paint and caulk where the casing meets the door jamb, siding, and miter joint.
    1. Use a flat pry bar to remove the door casing, being careful not to damage adjoining surfaces.
    1. Use a putty knife or chisel to remove any old caulking or thick layer of paint on the door jamb or siding.
    1. Measure from the bottom of the casing to the long edge of the miter joint at the top.
    1. Cut a 45° miter at the top of the casing.
    1. Cut the casing to length square at the bottom.
    1. Position the casing on the door frame.
    1. Nail the casing to the door jamb and wall stud.
    1. Caulk any nail holes, joints, and edges.
  1. Prime and paint the new door casing.

Watch this video to find out more.

Further Information

Exterior wood moldings are often the victims of water damage. The proper way to correct this problem is to remove the affected piece and replace it.

Begin by cutting any caulk lines adjacent to the piece with a utility knife, then carefully begin prying it loose with a flat pry bar. If it is attached to other undamaged molding, take care not to split the undamaged piece as you remove the rotten one.

Scrape off any remaining caulking from the surrounding area. Use plastic or composite material for the replacement piece, if you can find it to match the existing molding profile.

Simply measure and cut it to fit where the old piece was located and nail it in place with galvanized finish nails. Then complete the job by filling the nail holes with painter’s putty and caulking around the edges of the new molding.


  1. This video is a little misleading or incomplete. The initial photo shows a rotted jamb & molding, but the video only deals with the molding, the easy fix. What about the jamb?

  2. I have brick molding in brick wall for door opening. This is caulked now but caulk needs replacing. I just spent an hour removing a very small section of the caulk. I think all should be removed and replaced with new. I think the time element for removing the old caulk may be more than I want to dedicate to it. Would removing molding door frame and replacing with new and then putting in new caulking make more sense?

  3. I’m about to start however that sounds exactly what I was planning on doing well done for this website
    THANK YOU For saving me money friends , thanks Peter Schifone

  4. Thanks for the information. We just purchased a home but didn’t notice the water damage around the door casing. This will save a great deal of money and time.

  5. Without pictures, anyone googling how-to’s does not know how to do it. Building is tricky, from sewing a dress, to diy kits & especially home mainten. & repair. Know your audience otherwise you are writing the instructions just to be writing.

    • Hi, F.J.! We do have pictures for this how-to article — moving ones. The video accompanies this how-to article so fans can follow along. Thanks for your comment! 🙂


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