Chairs and chair rail may sound like they have a lot in common, but the relationship is limited to their approximate heights. Chair rail is the most misused and abused molding in new houses today. But it is also the easiest molding to install correctly, and one that can do the most to make a house feel like a home.

Yeah but…

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What? You want to argue the point? You still think chair rail should always sit at 36 in. from the floor? Sorry, there is no standard height dimension. In fact, historically chair rail started out very low.

Even in colonial rooms with 10-ft. ceilings, I’ve seen chair rail set at 30 in. from the floor. There are some 18th-century pattern books that show the chair rail at 24 in. off the floor. In fact, in rooms with 9-ft. to 10-ft. ceilings, this height is actually most appropriate for chair rail, and best falls within the rules of classical architecture (see photo, right). Over the past 60 years we have forgotten a lot about those classical rules, and we’ve forgotten how chair rail functions in a room.

A matter of scale…

Let’s back up a bit. Chair rail is a molding, right? The purpose of molding is to establish proper scale and proportion in a room. And because of its close proximity to us (chair rail is often the nearest horizontal molding we see) chair rail can do more to make a room feel right than either the baseboard or the crown. But get the chair rail wrong, and the room feels wrong—I can guarantee it.

Here’s where proper proportion comes into play. All of the classic architectural orders—the Tuscan, the Doric, the Ionic, the Corinthian, and the Composite—have strict rules of proportion. These rules of proportion were specified back in the first century BCE by Marcus Vitruvius Pollio, a Roman architect and engineer. Vitruvius used “modules” to ensure proper proportion.

He started with the spacing of the columns on a Greek temple, using that distance as a “module.” According to his instructions for achieving symmetry, harmony, and proportion, the base of a Doric column should be two modules and the height should be fourteen modules. That boils down to a proportional relationship of 1:7 — a column that is seven times as tall as it is wide. Put simply, if the base of the column is 10 in. wide, it should be about 70 in. tall. Of course, not all columns follow that same proportional rule.

How does all that relate to chair rail?

Ironically, the rules of classical architecture are really based on human scale, on the male body, and I’m the perfect classical specimen: My foot measures 11-in. long and I am 77-in. tall; a 1:7 ratio. Wow! (I pity you poor short carpenters with big feet!!!).

The moldings in a room are supposed to relate to our bodies, too. That is why you can walk into an old building and it just “feels” right. The reason it feels right is because it is symmetrical and harmonious to our own size. (See Fig. 1, below) We innately relate to and enjoy a space we fit into and fit well with.

Dig a little deeper and we find proportional rules for every architectural detail. Despite its name, chair rail actually corresponds to the molding at the top of a column’s pedestal.

Fig. 1

According to Abraham Swan, the Doric order didn’t even have a base because Vitruvius said: “This order is like a strong and robust man, such as Hercules, who was never represented but with his feet bare.”

Yet many later architects have included pedestals. For instance, when using a pedestal, Asher Benjamin divides the entire height of the Doric order into 80 parts. The diameter of the column equals six parts. According to Benjamin, the pedestal should be “two diameters and thirty minutes high.”

What’s all this mean to a carpenter?

Here’s how I look at it: Take a room with a 10-ft. ceiling, which is 120 in. Divide 120 in. by 80 parts. Each part would equal 1 1/2 in. Therefore, the column should be 9 in. to 10 in. in diameter (six parts). Multiply the column width by 2 1/2 to determine the height of the pedestal: 22 1/2 in. tall. Benjamin also suggests that the pedestal should be 15 parts high. Either way, the result is the same. Obviously, unless chairs were much shorter back then, the height of a chair has nothing to do with the height of the chair rail!

Wait a minute! Don’t leave the room yet! I’m not finished. We’re just getting started. Now we need to find out the exact size of each molding, from the plinth or baseboard, to the chair rail. Benjamin doesn’t provide that detail, but William Pain does in his 1778 book, The Practical House Carpenter.

Until the 1920s and 1930s, pattern books, like Pain’s, were used by carpenters and architects to duplicate classical details—and that means all molding profiles and proportions. But pattern books seemed to go by the wayside as minimalism and modern styles reduced the importance of moldings, and finally production trumped design. It’s no wonder that we so often hear from carpenters with questions about molding profiles, placement, and proportion. None of us were trained on the use of pattern books. And very few of the architects we work with are familiar with them. But that doesn’t mean we all can’t learn.

According to Pain, for a Doric pedestal, we start by dividing the height of the column into thirteen equal parts, where one part equals the diameter of the column. The height of the pedestal is set at 2 diameters and forty minutes, or 2.66 parts. For a room with a 10 foot ceiling, one part would equal 9 1/4 in. Forty minutes would equal about 6 3/16 in. That puts the pedestal about 24 11/16 in. from the floor. Let’s make it simple and add 1/16 in. Trust me. No one will notice.

Going back to William Pain’s book, we next divide the diameter of the column into 12 parts (9 1/4 in. ÷ 12 = 3/4 in.)

Pain then instructs us to divide one of those parts into 5—so 3/4 in. ÷ 5 = 1/8 in. (Well, not exactly, but it’s close enough for our purposes. Besides, that gives us a nice easy number to work with!)

Now let’s look at the three moldings that make up a traditional chair rail, and the sizes that Pain recommends for each one.

The cavetto, or cove molding, at the bottom should be 4 parts, which makes it 1/2 in., plus another 1/8 in. for the fillet above. The ovolo, or supporting molding, in the middle (sometimes this is an egg-and-dart profile, or a dentil molding), should be 6 parts, making it 3/4 in.; the corona at the top should be a bit more than 6 parts (I can’t read that number!), so let’s make it 7/8 in. (what the heck). There’s a fillet above the corona, and I can’t read that number either, but hey, it looks like 3/8 in. to me. Add all those crazy numbers together and we’ve got a chair rail that’s 2 5/8 in. No big surprise there, huh?

Too low is better than too high

The classical rules of architecture are the key to the proper size and placement of moldings in a room. Benjamin uses a slightly different set of proportional rules than Pain. But the overall effect remains the same. In the classically proportioned room, not only do we relate to the space, but the parts and pieces also “speak to” and relate to one another, from the crown to the base to the casing to the chair rail—and ultimately to us. Especially if weren’t not short with big feet.

When it comes to chair rail, I always advise customers to err on the side of too low rather than too high. Installing the chair rail or wainscot too high (see photo, right) diminishes the size of a room, making it feel uncomfortably squat and stuffed, kind of how you feel after eating Thanksgiving dinner.

Height isn’t the only problem we encounter when we install chair rail. Probably the biggest problem isn’t where to start it, but how to stop it—how to terminate, or resolve, the chair rail into casing, stairs, and other moldings. Here are some simple rules:

Never back-cut the chair rail at door or window casings.
Always butt cut the rail. If you’re running a build-up of stool and apron, notch the stool over the back of the casing, then butt cut or self return the stool; resolve the apron into casing.
Installing a backband is sometimes the best solution for terminating deep chair rail profiles.
Always install skirt boards on steps, even if there’s only one riser, otherwise, running the chair rail down the elevation change looks stupid.

Never interrupt the casing with the chair rail or with wainscoting! The casing is supposed to resemble a classical column, and should run uninterrupted from the floor to the top of the doors.

If you’re in complete control of a job, try to install the windows so that the window sills are the same height as the chair rail. But if the window sills are 40 in. from the floor, forgetaboutit! Run the chair below, and remember: it’s better to err on the side of too low rather than too high!

Well guess what? There is a language to classical design, too; a vocabulary that’s dependent on moldings for communicating purpose in a room. If you speak the language, all your finish work—your, bookcases, mantelpieces, doorways, and ceilings―will communicate fluently with your customers.

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If you don’t speak the language, your work will look funny and awkward. Put simply: You might be using the right words, but if you put them in the wrong order or upside down, they won’t make sense.

Supporting Moldings

Centuries ago, the Greeks and Romans worked out a set of rules for moldings. Each profile had its place and purpose. Some shapes were designed merely to embellish an architectural detail, while others served to separate architectural details. The two profiles that are most often confused and most often used incorrectly by today’s builders are terminating profiles that finish an architectural detail, and supporting profiles that hold or carry a weight above.

In the forward to Theory of Mouldings (C. Howlard Walker, reprinted 2007), Richard Sammons provides a great definition and an easy way of determining whether a molding is terminating or supporting. Sammons says that if the final line of the molding curve is pointing out, it is a terminating molding; if the final line of the curve is pointing up, it is a supporting molding. Or put another way, terminating moldings have a concave curve at the top, and supporting moldings have a convex curve at the top.

Let’s take a look at supporting moldings first. Supporting moldings have more meat or muscle on the bone near the top. They don’t look delicate! They look like a clinched fist on the end of your forearm. A perfect example of a supporting molding is a corbel, the embodiment of strength in architecture.

Some supporting moldings play a more subtle role. While the corbel forms the main support for the mantelpiece, look closely and notice the molding beneath the mantelpiece. You may be quick to label this profile as crown molding, but it’s actually bed molding. The top of the bed molding profile points up not out, so it adds another layer of visual support to the mantle above.

Band molding or panel moldings, in all their various shapes and sizes (from egg-and-dart molding to lamb’s tongue, to ogee chair rail and dado moldings), are another example of supporting moldings. The top curves on band and panel moldings are convex, putting muscle where it’s needed most – at the top of the profile.

Terminating Moldings

Terminating moldings are exactly the opposite, they’re much more delicate on the upper top edge, a clear sign that they’re not meant to support any weight from above. Though they might seem purely decorative, terminating moldings actually served an important purpose on classical structures. Like the brim of a hat, they helped deflect rain away from the wall below. Today, the most common pre-formed rain gutter actually uses a modified shape of crown molding, the most common of the terminating moldings.

The top of crown molding curves out, finishing the top of – or “crowning” – any architectural detail it’s attached to, from the mantle piece to the rake of the beautiful open pediment. Most crown moldings used today are called cyma moldings because they combine both concave and convex curves to form their profiles. Cyma recta is the classic crown shape with the top concave curve pointing out. On the other hand Cyma reversa, with the convex curve on top pointing up is the proper profile to use as a supporting molding, beneath a mantelpiece or a shelf.

One area that gets really confusing is crown molding at the corner of the wall and ceiling. Should crown molding at the ceiling be a supporting molding or a terminating molding? Actually, the wall in a home is meant to resemble a classical column – so the uppermost crown should be a terminating molding. But sometimes it’s not. I’ve frequently installed a supporting molding at the ceiling when I’ve used a one-piece crown, but most often when there’s a secondary soffit or light well above, which must
also be trimmed with crown.

Terminating moldings help produce dramatic effect at the top or termination of everything we build. As Marianne Cusato and Ben Pentreath put it in their book Get Your House Right, (also co-written by Richard Sammons): “The emphasis of a terminating molding, or cyma is outward.” That outward projection works as a lip or an outline to finish off any architectural detail.

Cyma Recta

No discussion of supporting and terminating moldings would be complete without a look at the two primal shapes that form the foundation for most moldings.

Cyma Reversa

These two opposing profiles follow the same classical rule: if the upper line of the molding points out, it’s a terminating profile. If the upper line of the molding points up, it’s a supporting profile. Supporting profiles always have more mass at the top. Terminating profiles always have less material at the top.

Cove molding is another profile that can be used as terminating molding. The delicate lip at the top of a cove’s concave curve works well to finish off less ornate architectural details. Many terminating crown patterns incorporate a deep cove to emphasize the projection of the terminating molding.

Finishing Up

Too often supporting and terminating moldings are installed backwards, upside down, or they are swapped in position and make no architectural sense. Too often a terminating molding is placed underneath something it can’t carry visually. For example, the ubiquitous 8010 crown should be used to finish off a detail, and too often we see it installed underneath something heavy, leaving us to wonder what it is about that detail that we don’t like or that doesn’t feel quite right.

The area in architecture where I see these moldings most often mis-used is mantles and shelves. It is very common to see a terminating molding get capped by a large block or thick piece of wood, which happens frequently with mantel shelves.

Wrong

I see this type of composition all the time! Now that you know better, it’s easy to see that the thin top of that crown molding isn’t strong enough to carry the weight of that heavy shelf. A supporting molding would have made much more sense.

Right

This is how a classical cornice should be constructed, with a cyma reversa supporting molding beneath the soffit and a cyma recta terminating at the top!

Never ask a terminating molding to visually carry something so large and heavy. And by the same token don’t finish off the top of a detail like a door header or mantle with a supporting molding that visually begs to carry something heavy above it.

Remember, a simple twist or rearrangement of words, and suddenly your sentences make sense—or they don’t! The proper use of terminating and supporting moldings can make your bookcases, mantels, cornices, and crown feel right and make visual sense. Understanding and applying these ancient rules will improve the value of your craftsmanship, and increase the value of your work in the eyes of your clients, too.

Read this article in its original format (with more images) at TiC Issue 1!