Baseboard, chair rail, and crown molding not only hide seams and gaps where the floor and ceiling meet the wall, but, with the many designs available, they offer a finishing touch that can be humble or ornate. It is important, however, to take one’s time with molding, as to insure that the job is clean.
One way to do this is ensure that the corners are snug, and with interior corners–because a 90-degree wall angle is never a guarantee–it is better to use a coping saw rather than trying to match up two 45-degree angles.
1. Install one side of the corner with a flat, 90-degree cut edge against the perpendicular wall. Make sure the gap, at the corner, between the installed molding and the wall is as minimal as possible, for this will make it easier to hid the gaps with caulk or wood putty.
2. Miter the connecting edge on the conjoining molding with a 45-degree angle.
3. Beginning at the top of the 45-degree angle, use the coping saw to remove exposed interior section of the molding. Follow the outline of the molding on the edge of the 45-degree cut and angle your saw to cut off the back section of molding. Cut as close to the exterior of the molding as possible, but be careful as to not cut too much.
4. Push the molding into the corner, and evaluate the fit. If necessary more of the molding can be removed with sandpaper or a wood file. Remember that patience will be rewarded in the end with a beautiful finish.
5. When the moldings fit snugly, install the other piece, and fill the gaps and nail holes with caulk or wood putty.