How Much Crown Molding Do You Need?
Calculate linear feet of crown molding plus inside and outside corner pieces. Includes waste factor for mitered joints.
Measuring for Crown Molding
Measure the perimeter of the room at the ceiling line. Add 6 inches of waste for each corner joint (miter or cope cuts produce small offcuts). Add 5% overall for measurement errors and test cuts. For a standard 12×14 bedroom: 52 ft perimeter + 2 ft corners + 3 ft waste = 57 ft → buy 8 eight-foot pieces.
Inside Corners: Cope or Miter?
Coped joints are superior for inside corners. One piece is cut square to butt against the wall; the other is cut along its profile with a coping saw to fit snugly over the first piece. Coped joints stay tight even as the house settles. Mitered joints are easier for beginners but open up as wood shrinks. For outside corners, mitered joints are the only option.
Installation Tips
Crown molding sits at an angle between the wall and ceiling — it is not flat against either surface. Mark the "spring angle" on your miter saw fence. Use a compound miter saw set to the correct crown molding angle (most common: 38° miter, 31.6° bevel for 52/38 spring angle). Nail into studs at the bottom edge and ceiling joists at the top edge. Use a stud finder — missing the stud is the #1 frustration.
Use construction adhesive (Liquid Nails) in addition to nails when installing crown molding. The adhesive holds the molding tight to the wall and ceiling while the nails dry, preventing gaps. It also reduces the number of nails needed, meaning fewer holes to fill.
