Crown Moulding

They say that cutting Crown moulding is a big mystery to most DIY-ers.

Nonsense! It’s as easy as cutting baseboard once you get the hang of it.

The first thing to know about crown is that there are two ways to cut it. Because of the design of crown moulding, the cut for a joint is a compound miter. It involves a miter angle and a bevel. This only applies if you cut the crown flat on the saw. The simpler way and the more economical way to cut crown is “In Position”. This simply means that the crown sits on your saw the way that it sits against the ceiling. The only angle to consider when cutting in position is the miter. The only limitation you may have here will be that the height of the fence on your saw will dictate the maximum size of crown that can be cut.

Safety is extremely important and that’s why adequate time is required to set up your work station. Make sure your saw is securely placed on a stand or on the ground with extensions or support blocks to hold longer pieces if necessary. Wear safety glasses and always pay attention to keeping your fingers clear of the blade.

You will require the following tools:

• Miter saw with crown stops if possible
• Angle Finder or Miter Gauge
• Air or cordless nailer or Hammer and Finishing Nails
• Shims
• Safety goggles
• Glue for the joints
• Sand paper
• Wood Filler and Latex Caulking

Cutting Crown “In Position”

The miter angle is the bisecting angle of the corner. By using a miter gauge or an angle finder (see image).

You can determine the angle of the corner in question and ultimately the cutting angle for the saw. Since corners are seldom 90 degree angles, it is imperative that an accurate angle for the corner is obtained.

You can buy a jig to mount onto your saw if your saw does not have crown stops. You can also build one out of three strips of plywood. These stops will hold your trim in the same position on the saw for every cut.

Crown Molding Mitering Fixture available at www.leevalleytools.com

Home made Jig to mount onto Miter saw

You will notice that the bottom edge of the crown moulding is always placed up on the saw. When setting the location of the stopper piece, ensure the crown is making parallel contact onto the vertical and horizontal pieces of the jig. Because crown comes in different styles, measurements “A” and “B” may differ. In order to keep the confusion to a minimum, you’ll need to prepare some sample cut pieces for yourself. Before you begin your project, you should have an extra piece of crown moulding that you can use to make these sample cuts to remind you of the direction of your cuts. There are four kinds of cuts:

Make a sample piece of each and label them on the face so that you can easily determine the types of cuts you need each time.

When measuring for your lengths, measure the wall section very accurately. Instead of bending the tape into the corners, try measuring away from the corner to a 10” mark and then measure to that mark and add 10” to than measurement. All measurements should be transferred to the bottom edge of the crown moulding. Since the crown is placed upside down on the saw, this mark is always visible. Make your cut and always keep it a slight bit longer, you can always trim the piece to master the length.

Before installing your first piece you should mark all of your stud locations for nailing. If installing in a condo or if studs are difficult to locate, you can cut a backing piece (the triangular corner of a 2x4) on a table saw and glue or nail it into the corner. The crown can then easily be face-nailed into this piece. The following diagram shows where nails should be placed on crown moulding. If using finishing nails and a hammer, you should pre-drill the crown if possible.

You should also mark a level line, either using a chalk line or individual pencil marks to mark the location of the bottom edge of the crown moulding around the room. This will ensure that the moulding is properly positioned everywhere on the wall.

When you go to place your first piece, make sure you have a sample piece for the joining sides to ensure the correct placement of your piece and a proper corner joint. Once the first piece is nailed into place you can carry on around the room. Glue each joint using wood glue prior to application.

On long runs where you have to join two or more lengths, don't simply make a straight cut on the two pieces. The correct method is to make beveled cuts. The result will be a much smoother seam where the pieces are joined. For example, the easiest cuts for butting two pieces together are the same ones you use on corners. You cut one for an outside left corner and the joining piece for an inside right corner. These two will fit together and give you a joint that can be sanded smooth and invisible.

A scarf joint is used on straight runs.

When all pieces have been installed, you can fill the nail holes with wood filler. Any gaps between the crown and the ceiling as well as gaps between the crown and the wall can be filled with latex caulking.

On walls where the crown moulding has to end on the wall, you will need to do a self return finish end. This is where the crown moulding returns into the wall. If the piece is running towards the right on the wall, you’ll need to cut the long run as the outside left hand piece. For the joining piece, that will return into the wall, you will have to use a 2’ piece and cut it as the outside right hand piece. You then cut the end off of that 2’ piece by laying it flat on the bed of the miter saw. The cut should be made at the mark where the miter cut reaches the bottom back side of the moulding. You will be left with a triangular piece that will fit into the end of your wall run. Glue and tape this piece into place. Once set, you can remove the tape.