How to Install Door Molding

Once your door frame is installed and your door operates properly it is time to finish the job with some decorative molding.

Installing Door Molding

Molding is used not only to make a doorway look nice, but it is also a way to keep air from flowing around the door and help reduce energy bills. Install-molding. com points out that this is not a one-person job, so round up a helper before you start your door frame finishing job. According to the Kelleher Corporation, one of the most popular ways to install door molding is by using a mitered frame. So that is what we will be doing. .

Measure the distance across the top of the door frame. Measure at least two or three times to make sure you are getting an accurate measurement.

Apply that measurement to one of the pieces of molding.

Make the two miter cuts on the piece of molding by setting the miter blade to cut at a 45-degree angle outward. Cut from the marks you made from your measurements.

Install the piece of molding you just cut to the top of the door frame. The proper alignment for this piece will be that the miter cuts will start at the door frame and angle out 45 degrees on both sides. Use finishing nails and a hammer to install the piece. Use a nail at each end and then two nails evenly spaced in the middle.

Make a 45-degree outward cut to one end of another piece of molding.

Make miter cuts on each of the two remaining pieces of molding so that one is for the left side and the other is for the right side at 45-degree angles.

Measure from the longer part of the top piece down to the floor. Make two or three measurements for accuracy. Add at least one inch to that measurement and cut each of the two side pieces to that length.

Fit the two pieces in to each side. If they are too long then make a mark and cut them to length. Once they are cut to length use the finishing nails and hammer to install them into place.

Use the nail set to countersink all of the nails on all pieces of trim. Be very careful when countersinking nails so that you do not damage the molding.

Use a putty knife to fill in the countersunk holes with wood filler. Use a wet sponge to remove the excess wood filler.

Use a fine-grade sandpaper to sand the wood filler after it dries, and then apply stain or paint to the door molding with a paint brush.

Things You Will Need

  • 3 molding pieces
  • Measuring tape
  • Marking pencil
  • Power miter saw
  • Hammer
  • Finishing nails
  • Nail set
  • Wood filler
  • Putty knife
  • Wet sponge
  • Light grade sand paper
  • Stain or paint
  • Paint brush


  • Miter cuts can be tricky. That is why you extend the side pieces by an inch. Once those pieces fit together, that inch may have been needed to make the piece work.

About the Author

George N. Root III began writing professionally in 1985. His publishing credits include a weekly column in the "Lockport Union Sun and Journal" along with the "Spectrum," the "Niagara Falls Gazette," "Tonawanda News," "Watertown Daily News" and the "Buffalo News." Root has a Bachelor of Arts in English from the State University of New York, Buffalo.