Place the first piece of trim along one wall with its square end flush against the corner. Do not attach the trim to the wall yet.
Using a miter saw, back cut the end of the trim at a 45-degree angle. If placed in the corner, the resulting cut would display the inside of the wood.
Flip the trim piece upside down and switch it to the other side of the miter saw, placing it face out. Align the trim so that the saw will cut off the angled end of the wood, removing a triangular chunk of wood from the end of the trim, creating a hollow behind the place where the trim will meet its neighbor in the corner.
Cut down into the base of the trim, continuing until your saw is slightly above where the top of the trim angles inward. Remove the triangular chunk of wood, leaving only a chunk of wood behind the angled top of the trim.
Using a Dremel with a drum sander head, hollow out the remaining wood behind the angled section at the top of the trim. Take care not to alter the front face of the trim in any way. The hollow section you are creating should be invisible when the trim is viewed from the front.
If the trim piece you are working with is longer than the length of wall you need to cover, cut the other end to the desired length.
Place the coped corner you just created against its neighbor in the corner. If there is a gap at the bottom, insert a small strip of cardboard behind the first piece of trim at the corner to correct the angle at which the pieces meet. Install both pieces of trim.
Things You Will Need
- Miter saw
- Dremel tool with drum sander head
- Coped corners can also be used when installing outside baseboard corners.