Throughout 2017, Dunn Solutions will keep up with Daniel Westbrook as he restores this historic Seattle residence. This video and post are a part of the ongoing series. For other related posts, click here.
One of the reasons I like working with historic homes is the endless architectural design details. It's pleasing to use creative techniques with moulding profiles to beautify a structure.
In the late 1800s, profiled mouldings became more standardized as machinery allowed millwork shops to be more consistent with their runs. Mass production made what would have been labor-intensive, hand-planed mouldings—generally affordable only to the elite—much less expensive, making them available to all. That period of time was the culmination of industrial ingenuity, gifted master craftsmen, and building standardization, creating what we know today as millwork. Crown moulding became popular in this era.
Crown moulding is often used as a transition between vertical and horizontal surfaces, for the gap between a cabinet top and ceiling, or as support for a mantel’s flat surface. A significant percentage of crown moulding, however, is used to soften the bare angle at the wall and ceiling transition, and create beauty in an otherwise empty space.
For our project, the architect designed soffits around the room that also intersect the custom cabinets, using the crown moulding to not only cover the top of the upper cabinet transition, but also fill the corners of the raised ceiling area, resulting in rich millwork. The last item to be installed is this crown moulding, and my job is to ensure all the components come together.
What Is a Cope Joint?
Before we dive in, let's review some terminology:
Cope Joint: Coping, or scribing, is the woodworking technique of shaping the end of a moulding component to neatly fit the profile of an abutting member.
Butt: The end of the piece.
Butt Joint: A technique in which two pieces of wood are joined by placing their ends together without special shaping. However in this case, the end is shaped to the profile like a butt cut.
Inside Joints: Slang for an inside corner wood interface. More commonly referred to as an inside miter, or an outside miter (if on an outside corner). The “joint” refers to whatever technique is used to make that transition. In this case, we are using a coping joint.
Cove Cut: The portion of the profile face that is a concave shape, or a cove.
A cope joint is simply a butt joint where the moulding meets at the inside corners. With crown moulding, 45-degree inside miter cuts can be really fussy, so I like coping my inside joints. Because it’s a butt joint with a profile, the pieces lock together, creating a solid long-term joint. The other advantage to a cope joint is that they’re consistently tight, which is great for the natural (or stain-grade) look.
The profile of the moulding is cut on the end to butt into the moulding at the inside corners. We used to do these cuts with a coping saw—a hand saw with a long, thin blade like a scroll saw blade—but these cuts can be done with any jigsaw, saving time and your arm's strength. It just takes practice and technique.
Setting the Crown in the Saw
First, it’s important to understand that crown moulding is generally not installed at a 45-degree angle, and the back is milled in such a way that it sits down on the wall more than it sits over the ceiling. The front is generally milled so the small cove cut is pointing down in a standard profile. This may not always be the case, so check your material.
The next thing to understand is how the material will be cut. It’s not complicated and doesn’t require math; it’s just a matter of perspective. Imagine the table of your saw as the ceiling, and the fence as a wall—this means the top edge of the crown will always sit on the saw table and the bottom edge will always sit against the fence. We always say “cut crown upside down and backwards.” For further insight, check out a crown moulding tutorial on Dunn DIY.
Take a piece of crown and lay it at an angle against the miter saw fence and table to find where it sits the best. The back-angle cuts on the back of the crown should sit nice and tight against the fence and table. Now mark the edge of the crown on the table, and draw a line parallel to the fence. This line becomes the reference point to consistently seat the crown in the miter saw, by installing a board on the miter saw stand to stop the crown in place.
Measuring the Crown
Make a mark on the saw fence as the crown sits on the saw, keeping in mind that the bottom of the crown is facing up. Remove the crown and measure up to the mark from the saw table. This is the same measurement as down from the ceiling to where the bottom edge of the crown sits.
Measure down in each corner from the ceiling and make a mark on the wall, then snap a line on the wall between the marks. This line represents the bottom edge of the crown—use it as a consistent point of reference when installing the moulding. The easiest way to install crown is to work from left to right. When doing a room with four inside corners, the last piece will have a cope on each end, so it's worth getting proficient at the differences in working positions as you cut a cope on either side of a piece.
Next, take a measurement at the snap line from inside corner to inside corner. This is the way each piece is measured, and the first piece is simply a zero-degree straight cut on either end.
Cutting and Coping the Crown
Once the first piece is installed, the second piece to the right is measured. At the miter saw, cut the left end of the crown with a zero-degree straight cut to clean up the end. Hook the tape measure on that end and mark the measurement toward the right, with the mark being toward the back of the crown on the top edge. (Remember: the crown is upside down in the miter saw, so it’s actually the bottom of the crown that’s being marked.) Move the saw 45 degrees to the left, and cut a miter with the long point exactly on the mark. This is an inside miter cut, or "cheek cut." This accentuates the crown profile and is also where the cope cut will be made. I like to lay the crown flat and clamp it on my saw table, sticking out far enough to create working room with my jigsaw. Once it’s clamped in place, it’s simply a matter of cutting along the profile. Slow and easy wins the race with this cut, and experimenting with different types of jigsaw blades might be necessary to find the one that works best for you.
The main thing to remember with this cut is that it can be worked from both ends, and keeping the blade so it’s angled back a bit from the face creates a relief on the back side of the crown, so when the joint goes together, the face of the crown touches first. The result is a tight fit. This does take practice, but it’s not a big deal if it’s paint grade, because the inside corners can be caulked. When it comes to stain-grade or natural-finish applications, I have found that a jigsaw blade that cuts on the down stroke is helpful in minimizing tear-out along the cut.
Installing the Crown
I always install the first piece of crown with finish nails back from the ends about 3’. This helps with adjusting the inside corners for fit—if it's needed—by moving the crown up or down. The second piece will have the cope cut on the left end, and the right end will be the end cut that butts directly into the drywall.
Work the cope first and get it tight by moving the fitted corner up or down. Sometimes I’ll have my carpenter take a small flat bar at the other end and wedge it between the drywall and crown end—just to nudge the piece and to tighten the cope a bit. Cope joints offer another advantage at times when there ends up being a tiny gap between the drywall and right end, because it’s pretty much hidden by the next piece. Sometimes I’ll run a bead of construction adhesive on the cope joint before I put it together to help hold the joint. Unlike carpenter glue, construction adhesive has body and can fill the void if one exists at the relief side of the joint without dripping out. Before gluing, it’s always best to test the piece first for fit. I’ll nail off the pieces starting at the left joint and work right to the other end. Stop nailing about 3’ from the right end.
Repeat the procedure until the final piece goes in. In a room with four walls, the last piece is coped on each end. Repetition has two qualifying signatures I value greatly. One is efficiency through practice, and the other is understanding the layers of the unique nuances of custom carpentry work.
Quality isn’t just the hands-on work of practicing the same cut a thousand times over, but the mental work of maintaining a positive attitude toward learning. That’s where quality is born.