How to Install Exterior Door Trim to Spruce up Your Entryway

Learn how to install decorative trim around a doorway for a quick, easy, and cost-effective way to add curb appeal.

Home with front porch and red door
Project Overview
  • Working Time: 1 day
  • Total Time: 1 day
  • Skill Level: Intermediate

Installing decorative trim around an entry door—whether old or newly installed—is a quick way to give your house a facelift. With the advent of urethane foam molding, there is now a wide range of affordable molding styles to choose from.

Urethane foam trim is light, paintable, easy to cut, and will never rot—ideal for exteriors. The trim shown here can be purchased at a home center. If you need more choices, check online sources. You may need to measure your door and order the header—the horizontal piece at the top—at a specific length. The casing (the vertical parts that replace the brick molding) can be cut to size.

To add trim to an entry door will take most of a day. It's a good idea to protect the area with a drop cloth.

What You'll Need

Equipment / Tools

  • Drop cloth
  • Tape measure
  • Hammer
  • Flat pry bar
  • Circular saw
  • Clamps
  • Utility knife
  • Nail set
  • Caulk gun
  • Putty knife
  • Sanding block


  • Urethane foam moldings to fit your doorway
  • 6d and 10d casing nails
  • Adhesive recommended for your moldings
  • Exterior caulk
  • Exterior putty


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    Remove Existing Molding

    Using a flat pry bar, carefully remove the brick molding from around the door. Be careful not to dent the siding or the jambs; using a scrap of wood as a fulcrum helps.

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    Scrape Off Any Extra Paint

    Scrape away any accumulated paint or putty from the jamb. If the reveal line is not clearly visible along the jamb edge, scribe a reveal line. If needed, seal and insulate the gap between the jamb and the framing with non-expanding spray foam insulation.

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    Measure for Header

    To establish the width of the header (the piece above the door), hold each piece of casing in place and mark along its outside edge. Measure between the marks. The header looks best if it extends beyond the casing; add twice the thickness of the header to the overall length and mark for cutting.

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    Miter Ends of the Header

    Miter the ends of the header. Urethane foam cuts as easily as wood, but a hard crust will build up if the saw blade binds and overheats. If this happens, pare off the crust with a utility knife.

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    Glue and Tape

    To assure that the header will stand proud of the casing:

    1. Glue in place urethane parting stop along the inside of the top and bottom of the header.
    2. Cut small mitered pieces of the header to create a return.
    3. Glue and tape both pieces in place.
    4. SDW_142_07.jpg

      Cut and Attach Casing

      Cut the casing to length. Position each piece of casing and check that it meets against the reveal line. Drill pilot holes and attach the casing with 6d casing nails driven into the jambs and 10d nails driven into the sheathing and studs.

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      Set Header in Place

      Set the header in place and center it so it extends equally beyond each piece of casing. Drill pilot holes and fasten it as you did the casing.

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      Set Nails and Caulk

      Set the nails and fill with exterior wood filler. Sand the filler when it is dry. Apply exterior-grade caulking all around where the molding meets the siding.

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