Triple Layer Crown Moulding

Look at this monstrosity! It's ridiculous! This, my friends, is triple-layer, corniced crown moulding. This is the great Satan of crown moulding, but damn does it look good.

I've been in the works of restoring our parlor since September 2017, when we had to tear down the lathe and plaster ceiling due to water damage. Twenty-five hundred pounds of trash later, the ceiling was down and we put up a new drywall one.

The ceiling though is a good 10 feet high and had no trim whatsoever around the top. So off to research historic crown moulding on Federal houses I went, and the triple layer cornice is the poison I chose. This design is one of the "classics" that can be seen in all sorts of historic buildings of the Georgian and Federal eras, including Monticello.


The picture to the left is a 21st-century reproduction of the moulding from Monticello that was created by the folks at Colonial Williamsburg using the traditional methods. If you've never seen someone make moulding using a hand plane, it is a specticle to behold. It's worth the YouTube. One thing worth noting about this picture is the acorn between the dentils on the bottom piece mouliding. I'm guessing that each of those was individually carved by hand. I would hate to be the apprentice joiner on that job. You will notice that the acorns are absent from modern reproductions because even robots don't want to put forth that level of effort.

If you want to put together one of these beauties, it's actually easier than  at looks. Mounting the cornice is the most important part because it bears all the weight from the other two pieces of moulding. You will need to mount it. If you try to float it, everything will bow and it will look terrible. Once you have that mounted to the wall and ceiling the other pieces are very forgiving. Side note: the moulding at Monticello is floating, but that's because the pieces are jointed using a sliding dovetail joint, which is much stronger that modern finishing nails.

To make the cornice, you will need a table saw, a router table with a 1/2 inch cove bit, and a finishing nailer. The wood required for an eight foot section is 1 1x2x8, 1 1x3x8, 1 1x6x8, and 1 1x8x8. Total cost for the wood is about $30.

The first thing that you want to do is mount the 1x3 to the wall 5 1/2 inches down and the 1x2 to the ceiling 5 1/2 inches in. I make a gauge the distance of the space from the edge of the board to the wall or ceiling to make mounting go by much faster.

Then you will rip the 1x8 to be a true 1x6 (a purchased 1x6 is only 1x5.5), and rout out the cove on the bottom of that board. You will then attach your plain old 1x6 to the coved 1x6 right where the cove ends to make what looks like half of a 5 1/2 x 5 1/2 decorative box. Once the box is done, simply attach it to the mounting points on the wall and ceiling with the cove part facing downward, and you will have one safe and secure cornice.

Attaching the dentil and top crown are easy after that because you are just treating the cornice as either a wall or ceiling so it is very forgiving. Just hope that your corners are square, otherwise woodfiller is your friend. (Wood filler and I are besties.)