Conventional Crown Molding: Tips and Tricks for Installation

By Matt Weber

Planning

Fortunately, with ceiling trim there are generally no doors or other room openings with which to contend. This simplifies the layout somewhat, but you should plan the layout with the intention of coping the inside corners. Since inside miter joints are very likely to open, coping the joints hides this problem. In a basic square-room installation, the first piece of crown should be installed on the wall opposite the door with two square-cut ends butted tightly to the wall surfaces. Then proceed around the room with the next adjacent pieces having one square end and one coped end, which installs against the butted first piece. This means that as someone walks into the room, they are presented with the best face of the crown joints on the opposite side of the room. The final run of molding, above the door, will have two coped ends—but these are at the least noticeable locations in the room.

I should note it is difficult to successfully fit a piece of molding that is coped at both ends—even for a pro. To make this easier, you can fit each coped corner on a separate piece of molding and cut a scarf joint to join the two pieces in a continuous run.

More on coping and scarfing later.

Prepping

Naturally, you should take all the linear measurements of the room’s walls to determine how much molding you’ll need. And always purchase a few extra sticks of molding to compensate for the waste cuts and for any mistakes you make. Collect all materials and tools on site.

For a basic single-piece molding installation, the crown will install against the ceiling. (However, for more complex built-up molding profiles, you should sketch your custom profile on paper, determine the measurements and snap a level chalk line around the room—but that’s another story).

Since the molding I was installing was so small, I masked the top of the ceiling in painter’s tape. This served two purposes: First, the tape was wider than the installed molding, so I went around the room with a stud finder and pencil, marking the stud locations on the bottom edge of the tape. When I placed the molding over the tape, I could see my stud marking and know exactly where to nail. Second, after the molding was completely installed, the tape was already in place to mask my painting. Once the paint dried, I just cut away the excess tape. Whether or not you use this method, you still need to mark the wall stud and ceiling joist locations—perhaps with tabs of tape—to guarantee solid backing for your nails.

When cutting the moulding on a power miter saw, position the strip upside-down and backward, so the miter fence acts as the house wall, with the saw base representing the ceiling.

Cutting and Installing

As noted earlier, start with the wall farthest from the room’s entry. Install the first run of molding with square-cut ends, butting it against each corner. Next, measure out from the corner along the adjacent wall (adding a couple of inches) to find the rough length of the coped molding.

 For long runs of moulding, scarf two strips of moulding and fasten over a stud. For inside corners, begin coping the joint by marking the profile on a 45-degree miter. Coping is an alternative to miters, in which the molding profile, or shape, is duplicated to nest tightly against the face of the adjoining molding for a “perfect” fit. Transfer your measurement onto the intersecting end of the second piece of molding, and cut a 45-degree inside miter. Run a pencil along the mitered edge, marking the edges and curves for better visibility.

Clamp the molding securely and use a coping saw to back-cut along the pencil line, following the contours of the profile. Keep the blade 1/16 inch to the waste side of the cutline. Then use a file to clean up the profile, revealing a shaped edge that will be the only point of contact between the intersecting molding pieces. This should create a socket that fits snugly over the face of the first piece. After checking for fit on the wall, cut the uncoped end square and butt it against the far corner to meet another coped piece on the next wall.

More Tips for Molding and Trim

 Smooth Cuts—For the best appearance, cut into the finished face of the molding to prevent tear-out. With power miter saws, use a fine-toothed blade. When cutting with a miter box, try candle wax or furniture polish to lubricate the blade.

 Nail it right—On this job I was eager to test a new Kobalt belt-mounted CO2 regulator, so I used a pneumatic finish nailer. You can pick up the regulators at Lowe’s, and it’s like having a miniature air compressor on your tool belt—a really clever idea to power air tools. The regulator performed very well, and so did the nailer for that matter. But a word of caution: You must be extremely careful when using a powered nailer on trim. While it’s faster than a hammer and nail, the tip of the nailer can also damage the trim, forcing you to repair dings and dents on the new molding. I admit, after installing the crown, I had some puttying to do.