How to Join Crown Molding Invisibly

While you can get crown molding in lengths all the way up to 16 feet, the easiest length for most of us to handle (and the most common length) is 8 feet.

The problem with these shorter lengths is lots of walls are longer than 8 feet, so your choice is either to wrestle with a longer piece or join a couple of shorter pieces and ensure the joint isn't visible. Here's how to join lengths of crown molding invisibly.

Ensure that you understand how crown molding is designed to work. When you look at a piece of crown molding the back edges are angled. This is because crown molding is designed to fit into the angle to fit into the angle between the wall and the ceiling. One edge will fit against the ceiling while the other fits against the wall. For this reason you don't cut crown molding from the front, but from the back. You lay the molding down on the molded side and cut from the smooth side.

Make a couple of practice cuts on a piece of scrap molding. Set your saw angle to 45 degrees; position the molding upside down and hold it firmly against the fence on your miter saw before making your cut.

Remember, you will need to make two 45-degree cuts, one open to the right and one open to the left.

Measure your wall to determine how long each of your pieces needs to be cut. Don't just divide the wall in two and plan on cutting each piece to be half of the length. That will place the seam right in the middle of the wall, and people's eyes are drawn to the middle of the wall.

Mentally divide the length of the wall into two uneven lengths to make the seam invisible. For example, if your wall is 12 feet long, make one piece of molding 5 feet long and the other 7 feet.

Carefully measure your first piece of molding and make your cut, then install it.

Position your second piece over the installed molding and mark EXACTLY where the front of the molding piece should be cut.

Reverse the angle of your saw and make your second cut.

Spread wood glue on the open areas of the molding pieces and install the second piece. Use a couple of finishing nails driven through the overlapping sections to hold them in place.

Allow the glue to dry, countersink the nails and fill in the nail holes, then joint line with Spackle.

Things You Will Need

  • Power miter saw or miter box and back saw
  • Ladder
  • Measuring tape
  • Wood glue
  • Spackle
  • Finishing nails

Tips

  • What you are creating is known as a "scarf joint," in which the two pieces of molding overlap. Because the pieces are cut at an angle they won't separate as pieces cut on a 90-degree angle might.
  • Save yourself lots of effort by painting all your moldings before installing them.
  • Use Spackle (not caulking) to fill your nail holes. It's easier to sand and will take paint better than caulk.

Warning

  • Always wear eye protection when working with a power saw.

About the Author

I learned home repair and maintenance hands on. Over the past 30 years I've built sheds, decks, fences and gates and planted numerous trees and shrubs. Inside I've done all the common jobs like repairing and installing toilets, plumbing and light fixtures plus I've transformed three basements from bare concrete floors and walls into warm , bright family rooms. I write on home maintenance and repair for DoItYourself.com and answer maintenance and repair questions online at MyHomeImprovement.com.