Crown mouldings create a decorative transition between walls and ceilings. They can take an ordinary room and transform it into a warm and comfortable place.

However, installing crown moulding can be a tricky process and you may want to consider hiring a professional to do the job. However, knowing the right tools and techniques can make an easy job of cutting and installing mouldings.

The biggest problem has always been cutting the angles, rather than the actual installation. The trickiest part is to know which way to hold the moulding on your saw or miter box's bed. If the moulding is not too large, then the preferred method is to hold the moulding on an angle from the base of the saw to the fence at the same angle that it will be installed on the wall. And most importantly it goes on the bed upside down and backwards. That is, the bottom of the moulding is placed up and the bulk of the workpiece is to the right of the saw blade when cutting for a left corner on the wall and vice versa. This method allows you to make compound cuts on a single plane saw (such as older miter saws or miter boxes).

If the moulding is too large to sit on an angle on your saw, then a compound miter saw is required and you will need to know the bevel and miter angles. We will discuss this later.

There are usually only five different cuts to make when installing crown mouldings - left or right inside corner, left or right outside corner or a splice to join two lengths of moulding on a long wall. Looking at a corner (inside or outside), the piece of crown which will be attached to the wall on the left of the corner is an "inside left"or an "outside left", and vice versa for the right hand side. Some corners are not exactly 90 degrees. If you want 100% accuracy, a large plastic moulding protractor can be used to measure the angle of the corner. Divide this angle by 2 and set your saw accordingly. This step is optional and only works if you have an adjustable miter saw not a miter box.

The following pictures illustrate the four different set ups for 90 degree corners:

Inside Left		Outside Left
Inside Right		Outside Right

To Summarize:

Take a 2 foot sample of the crown you are working with and make the following cuts on it ( bottom edge up!):

• on an INSIDE LEFT corner, the blade is 45 degrees to the right, and the bulk of the workpiece is to the right of the blade.
• on an INSIDE RIGHT corner, the blade is 45 degrees to the left, and the bulk of the material is to the left of the blade.

Now cut off about 4" from each end, preserving your right inside and left inside cuts and write what they are on the back. Set aside and save. Now you have templates to refer to as a check before you cut any real crowns. This can save you many feet of moulding.

Now do the same for on outside corner making the following cuts (remember bottom edge up!)

• on an OUTSIDE LEFT corner, the blade is 45 degrees to the left and, and the bulk of the material is to the right side of the blade.
• on an OUTSIDE RIGHT corner, the blade is 45 degrees to the right, and the bulk of the material is to the left side of the blade.

Make your reference templates.

The templates are used as visual checks so that you always make the right cut.

Crowns too tall to cut when set on an angle from the base to the fence in your saw can be cut on the flat if you know the miter and the bevel angles. The following diagrams and table will assist you in performing these compound cuts for the two most common crown angles 45 degrees and 38 degrees.

Type of Crown Moulding	For processing crown moulding at positions and in Figure 2		For processing crown moulding at positions and in Figure 2
	Miter Angle Setting	Bevel Angle Setting	Miter Angle Setting	Bevel Angle Setting
45° type	right 35.3°	30°	left 35.3°	30°
38° type	right 31.6°	33.9°	left 31.6°	33.9°

1. Settings to cut crown mouldings at positions and in Figure 2
   1. Turn the Turn Table to the right, and set the Miter Angle as follows:
      • For 45° type crown mouldings: 35.3°
      • For 38° type crown mouldings: 31.6°
   2. Tilt the Head to the left, and set the Bevel Angle as follows:
      • For 45° type crown mouldings: 30°
      • For 38° type crown mouldings: 33.9°
   3. Position the crown moulding so that the upper surface ( in Figure 1) contacts the Fence
2. Setting to cut crown mouldings at positions and in Figure 2
   1. Turn the Turn Table to the right, and set the Miter Angle as follows:
      • For 45° type crown mouldings: 35.3°
      • For 38° type crown mouldings: 31.6°
   2. Tilt the Head to the left, and set the Bevel Angle as follows:
      • For 45° type crown mouldings: 30°
      • For 38° type crown mouldings: 33.9°
   3. Position the crown moulding so that the upper surface ( in Figure 1) contacts the Fence
3. Settings to cut 45° type crown mouldings for 22½° corners.
   1. Set the Miter Angle to 17½°
   2. Set the Bevel Angle to 15°

Install the mouldings piece by piece, working your way around the room. Avoid nailing the last 2 inches or so of each piece to prevent splitting. Nail mouldings into wood studs or jambs.

To span longer lengths may require splicing the crowns. Cut the joining ends at a 90 degree miter and a 45 degree bevel. One piece will overlap the other in a scarf joint, (see figure3), creating a vertical face seam in the finished installation.

In places where it is difficult to find studs, you could add backing trim to make a solid nailing surface for moulding (see figure 4). Adding a profiled piece of flat stock not only increases the nailing surface for any crown moulding, but it's also a way of making a fancier moulding without a lot of extra work. Any number of simple profiles can be routed on the edge of the stock. Alternatively, crowns can be combined with other profiles such as casings or baseboards to create the look of custom millwork. Screw the backing to the wall or ceiling after locating the studs, joists or strapping. The holding and biting power of a screw is much more solid than a nail, especially when dealing with wooden lath or loose studs.

If you wish to stay with a single piece crown and require backing, then you could put up a backing (cant strip) made from 2 x 4 or any other inexpensive wood, cut down in a triangular shape. (See figure 5). Leave a small gap between the crown and the backing to allow for uneven walls and ceilings.

Coped joints require more labour, but result in a tighter joint. Often an inside miter joint opens up as it is nailed because it is drawn in tighter than it could be held by hand. The coped joint avoids the problems. Cut the crown moulding as you would normally for an inside miter. To establish a cutting line, highlight the profile shape by marking along the front edge of the profile with pencil. Cut to the line with a sharp coping saw (see figure 6), back-cutting it a few degrees. The first piece of crown in a room can usually be square cut at both ends. Often, the last piece of crown in a room has to be coped at both ends. A long moulding can be cut slightly longer than necessary and snapped into place.