9 steps for cutting precise outside crown molding corners

Cutting and matching up crown molding for outside corners is among the most difficult jobs when installing trim. Here are 9 steps for cutting precise outside crown molding corners.

The reason: Crown molding doesn’t rest flush against the wall. If it did, says Leah Bolden, a master craftswoman and founder of the home-improvement site See Jane Drill, a simple miter cut would work. Instead, the top of the trim rests against the ceiling and the bottom against the wall, creating a spring angle.

The spring angle is the triangle of dead air space behind the trim when it’s pressed into place. That spring angle requires the installer to do a combination miter cut so the piece of trim on one wall leading to the 90-degree corner will be a perfect mirror image of the piece on the adjoining wall, allowing the two to fit together like pieces of a puzzle.

Here are 9 steps for getting there:

1. For cutting precise outside crown molding corners, start by pressing a piece of crown molding against the wall. The length should be slightly longer than the distance from the inside corner of the next wall to the outside corner. Place the edge with the more prominent decoration against the wall; the plainer edge is the top and goes against the ceiling. Extend the piece beyond the corner.
2. Using a Sharpie or a pencil, draw a reference line on the trim near the edge that you will cut for the corner. The reference line will remind you which direction to set the blade on the miter saw.
3. Now it’s time to cut — and here’s where you can go wrong. First, if you set the piece against the miter saw exactly the same way it rests on the ceiling, so it forms a spring angle as it did on the wall, you’ll see that it’s nearly impossible—and also dangerous—to cut it at that angle while you’re trying to hold the molding in place. Second, once you turn the saw’s blade so it will cut the angle indicated by your reference line, you’ll see the cut will be wrong because of the spring angle.

Solution 1: Rest the piece against the saw’s fence, making sure the more decorative edge is on the bottom.

Solution 2: Flip the piece upside down so the face still is toward you as you cut. The plainer top edge now is on the bottom and your reference mark is on the opposite edge. Press the piece against the bottom and fence of the saw to hold it in place.

4. Make the cut.
5. A second cut on the other side will make the piece fit perfectly into the space between the inside and outside corners of the wall, says Chelsea Lipford Wolf, daughter Pro Danny Lipford, the host of Today’s Homeowner. Measure the molding and mark it on the other side—on the top—starting from the shortest corner of the angle you just cut.
6. Match it to the saw blade so the blade will hit the mark. Adjust the saw blade to the opposite 45-degree angle; that is, if your first cut was with the 45-degree marker on the left, rotate it to the right.
7. Hold the molding tight against the fence on the angle, the same as the first cut.
8. Bring the board back to the wall. Push the side with the first cut to the very edge of the wall; the miter cut will be on top.
9. Do the same with the piece of trim that will meet the first one on the adjoining wall at the outside corner. The two should meet perfectly.

– Sharon O’Malley