DIY Cutting a Scarf Joint in Crown Molding

Scarf joints are used to join two straight lengths of molding together to create one long section.

The joint is cut at a 45 degree angle to create a less noticeable joint. Mastering the scarf joint is essential to a successful crown molding installation. Once you learn how to cut a scarf joint, your next crown molding installation should be a breeze.

Measure the wall to determine the length of the two crown molding segments necessary for the scarf joint.

Set the miter saw to cut a 45-degree angle with the saw blade oriented to your left. Measure and mark the crown molding section to length. Align the measurement mark with the saw blade. Hold the molding in place as it would be located on the wall and ceiling, using the fence as the "wall" and the table of the saw as the "ceiling" on the left side of the saw table. Cut the section of crown molding to length at a 45-degree angle.

Adjust the miter saw to cut a 45-degree angle with the saw blade oriented to your right. Measure and mark the second section of crown molding to length. Align the measurement mark with the saw blade. Hold the molding in place as you did with the first section, only this time you will hold the board on the right side of the saw table. Cut a 45-degree angle in order to cut the section of crown molding to length.

Place the two mitered ends of the molding together to form the scarf joint. Inspect the fit of the joint. Measure the total length of the molding. Make slight adjustments if necessary by trimming the joint for fit.

Sand off any blowout on the back edge of the mitered cuts with sandpaper. Always sand with the grain of the wood.

Things You Will Need

  • Tape measure
  • Pencil
  • Crown molding
  • Miter saw
  • Sandpaper

Tip

  • Practice making scarf joints on scraps before cutting your expensive project material.

Warning

  • Wear eye protection when working with wood.

About the Author

Jonah Morrissey has been writing for print and online publications since 2000. He began his career as a staff reporter/photographer for a weekly newspaper in upstate New York. Morrissey specializes in topics related to home-and-garden projects, green living and small business. He graduated from Saint Michael's College, earning a B.A. in political science with a minor in journalism and mass communications.