Building Custom Crown Molding
Our generation looks back on old homes as the epitome of craftsmanship. They were generally well made, but they were built for a working class market by practical contractors.
There’s a neighborhood near my home that looks like it was torn from an early 1900s magazine ad for bungalow homes. When I did a recent estimate there, it almost felt as though I should have been wearing a bowler hat and a handlebar mustache. I still haven’t heard back from the client about my bid, but visiting their home did inspire me with a couple of ideas for replicating simple moldings.
It’s a little ironic that our generation looks back on these old homes as the epitome of craftsmanship. It’s true that they were generally well made, but they were built for a working class market by very practical contractors. Trim details were fairly simple, and designed to maximize the installer’s efficiency. The old timers purchased their parts right off the shelf, but we’ve got to start from scratch.
SELECTING STOCK FOR CUSTOM MOLDING
Selecting stock is the first step, and douglas fir was the traditional choice. Redwood was also used, and if you’re planning a clear finish, either of these woods are ‘authentic’ options. I’ve seen both of these woods with paint finishes, but I don’t know whether the paint is original or a later change. In any case, I prefer poplar (about $2.60 a board foot in my area) for paint grade work; oak, ash, or birch/maple are my picks for stain grade work.
This piece can be used as either a plate rail or an accent molding, depending on how it’s scaled. It’s usually installed with the rail leveled to the tops of the head casings on the room doorways. This would be my choice for a plate rail, since there would be less chance of a plate being knocked off the wall. Check the casings out with a water level before proceeding, since they might be at different heights. A smaller-scale molding would look okay nailed on at 3/5 of the wall height (about 57-5/8").
Rip the frieze boards to width and dress the cut edges; I buy lumber that’s straight lined on one edge and use a planer for clean up. Cut the boards to manageable lengths and radius the lower edge. You can run an ogee if you wish but this is a little more decorative than the early 1900’s work I’ve seen. Back-bevel any ends that will die in an inside corner, and use a cope joint where the friezed continues through the inside corner. Longer sections should be scarf-jointed, and bevel the front of any piece that will butt against an existing jamb casing.
The cap rail can be made a couple of different ways, depending on the desired use. If it’s intended for plates, run a 3/8-inch dado the length of the rail, and mill the front edge as desired. It may be tempting to rout this dado with a core box bit, but don’t do it -- plates edges won’t ‘catch’ on the rounded groove. The back edge can be beveled if you’re planning to scribe the rail to any irregularities in the wall. But unless the wall is badly out of plane, I’ll skip this step for paint grade work. Read our article on how to cut crown molding for more tips.
Figure 1: A look at the rail cap showing the plowed plate groove (it would look nice if the groove were half-round, but I think the plates would simply slip out!). The 3/8"x3/8" groove was made by using multiple passes over the saw blade. Building custom molding.
Figure 2: Rip the 8/4 stock to a rectangular cross section, then cut a bevel along its length. For a more sophisticated profile, mill it with a large router. Clean up all the milled edges prior to cross-cutting the blocks to length. Making custom molding.
Corbels, or decorative brackets, are the next order of business. Despite the dressy appearance, these things are simple to mass produce. The profile of the smaller, angular brackets is ripped on the saw, and then individual pieces are cross-cut to length. Use a sharp blade and a stop block clamped to the fence, like the setup shown in figure 3.
Figure 3: After dressing the edges of the 8/4 blank, cross cut the blocks to length using a stop block clamped to the fence (don’t run the stock directly against the fence when using the miter gauge, which can cause binding and kickback). Cutting custom molding.
The quarter-circle corbels are slightly more work to produce, but most of the effort is in the set-ups. Rip the stock (in this case, 8/4 poplar) to width and dress the edge as usual, then cut the corbels to length. The quarter-circle cuts are made with a hole saw, using a simple fixture to index the blanks. Smooth the finished blanks with a drum sander or some sort of sanding equipment.
Figure 4: Take a look at how the bevel on the ripped stock has resulted in a nice profile on the completed block. Sand any rough edges and attach it to the plate rail, repeat 40 or 50 times and paint. how to make custom molding
ASSEMBLING CUSTOM MOLDING
Assembly can follow a couple of different routes, depending upon your particular needs. With just a short run of this molding, you could pre-assemble everything in the shop; by doing it this way, you could blind nail the corbels from behind the frieze, if you’re using stain-grade stock. This method would lend itself to building a free-standing plate rail, too.
If the molding does have to be built up on site, then install the friezes on the wall first. Locate the studs and lightly mark them with a pencil, and install the longest friezes with finish nails. Any adjoining, shorter runs of frieze are coped to fit at the corners, though miters or butt joints can be used if preferred. Make sure the level line for the frieze compensates for the thickness of the cap rail (as in the accompanying drawing), and nail the frieze in place. Consider using a DEWALT laser level.
For a single wall, the first corbel is installed on the center line of the frieze. The distance between the center line and the wall is split in two, determining another corbel location. Continue in this way until the space is filled with sufficient corbels – a judgement call you or your client will have to make. Consider using a laser distance measurer for this task.
Corbel spacing, while discretionary on a single frieze, must be consistent on multiple friezes. After installing all friezes, find their centerlines and determine corbel spacing before you install them. Do this on paper first, or you’ll wind up with nail holes all over the frieze (where the corbels were nailed in place but "just didn’t look right").
Nailing is the simplest means of attaching the corbels, and it goes a lot faster if you’ve got a cordless finish nailer. You can also pre-drill angled holes for toe nails or drill through the front for a single wood screw. Use some glue on the back of the corbels, and make sure they’re installed plumb. Let the glue cure completely before painting the molding. It’s okay to let somebody else handle that part of the job, since you’ve taken care of all the hard work.
About Leland Edward Stone:
The author is a California-licensed general contractor who enjoys both hobby and professional woodworking. He frequently writes about the business and technology of construction and woodworking topics for trade audiences.