Known as splicing or a scarf joint this task is fairly simple with the right tools.
Join crown molding middle wall.
Set your miter saw to 22 1 2 degrees and make scarf cuts with the molding upside down just as you did for other miter cuts.
When it can t two lengths join end to end in a scarf joint 4.
Join sections of crown on long walls using scarf joints.
Use scarf joints on long walls.
Most crown comes in 16 foot lengths so unless you re trimming out a gymnasium a single piece can usually span each wall.
On occasion you may find that you need to join 2 pieces in the middle of a wall.