There are several types of cuts typically required when preparing baseboard molding for installation:
- Square cut - Also known as a "butted" cut, this cut is made 90 degrees to the face and edge of a board. It's useful where moldings butt against the wall surface at inside corners and at door casings.
- Miter Cut - Moldings are cut at 45 degrees to their face so they meet to form a 90-degree corner. This kind of cut is used where two pieces of molding meet at outside corners. To connect two pieces with this cut, use wood glue and cross-nail the joints with 4d finishing nails.
- Bevel cut - A bevel cut is made at a 45-degree angle to the faces. It is used where two pieces of molding must be joined along a long wall. The joint should fall over a stud and it should be adhered with wood glue.
- Coped cut - Using a coping saw, cut where the end of one piece of shaped molding joins another already installed in an inside corner. Typically, you should cut the coped end first and test before cutting the other end to length. In three-piece installations, the base molding is usually square-edge stock so coping is not required. Detailed base molding, as well as cap and shoe moldings, however, should be coped at inside corners.
Miterless baseboard molding is installed with square-cut ends between corner blocks (at inside and outside corners) and plinth blocks (at door openings). The components are generally nailed and glued to the wall with panel adhesive.
Ideally, all cuts would be exactly 45 or 90 degrees. But not all corners are square. "Out-of-square" corners (inside corners are often greater than 90 degrees and outside corners are often less due to drywall taping compound) often necessitate minor adjustments, as do "out-of-plumb" walls.
A power miter saw will give far superior results with much less work than using a hand saw or hacksaw and hand miter box. If you cannot justify purchasing a power miter saw, you can rent one. It's well worth the cost. Be sure to read the manual and learn how to use the tool properly. Take the time to set up proper supports for your molding so it won't splinter when cut. It should sit flat on the saw table and the waste should not fall off after the cut. Never use a miter saw without the required safety guard.