How to Install Exterior Door Frame Molding for a Quick Update

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
  • Estimated Cost: $3-$6/linear foot
  • Yield: One framed door

Adding door frame molding around an entryway—whether existing or newly installed—is a quick way to give your house a facelift. With the introduction of urethane foam molding, there's now a wide range of affordable styles to choose from.

Urethane foam door frame molding is light, paintable, easy to cut, and will never rot—ideal for exteriors. You can buy trim at a local home or hardware store or online. 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.

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

What You'll Need

Equipment / Tools

  • Drop cloth
  • Tape measure
  • Flat pry bar
  • Paint scraper
  • Pencil
  • Circular saw
  • Utility knife
  • Drill
  • Hammer
  • Sanding block
  • Putty knife


  • Urethane foam moldings to fit your doorway
  • Spray foam insulation (optional)
  • Glue
  • Painters tape
  • 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 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 using a circular saw. 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 ensure 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.
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    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 hammered 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 them with exterior wood filler. Sand the filler with a sanding block when it is dry. Using a putty knife, apply exterior-grade caulking around where the molding meets the siding.

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