Crown Molding Corners: Inside, Outside and Coping

The stick is the easy part. The corner is where crown looks built or looks forced. Spectis polyurethane cuts like paint-grade wood. The spring angle still belongs to that profile.

Inside corners

Two choices. Cut two compound miters that meet, or cope one piece over the other. A cope is the profile shape cut so it overlaps the adjoining stick. Coping hides a wall that moves a little through the season. Miters are quicker when the corner is actually square.

Outside corners

Outside corners are compound miters. Dry-fit them. Glue the miter faces with PL Premium (PLP100), then pin.

Upside down and backwards

On a miter saw, nest the crown against the fence and the table at its spring angle. The piece sits the way it will sit on the wall, only upside down. The spring angle is on that SKU’s drawing. It is not the same number for every Spectis crown.

Walls that are not square

Measure the real angle with a protractor and split it. A 45-degree miter on an 88-degree corner opens at the face.

Joints on a long wall

Where two sticks meet in a run, glue both faces with PLP100. Keep that joint off a focal point. A scarf joint is the usual way to hide the seam in paint-grade work.

Dentil and ornament

Lay the repeat out from the corner so a block or a motif lands cleanly on the miter. Do not center a tooth on the joint and hope caulk will hide it.

Flat-base and large crowns

Install backing blocks before the stick. Drywall alone will not hold a deep cornice. The field sequence is on the install notes.

Further reading: the crown install guide and PL Premium adhesive.