Where the Wall Meets the Sky: Cornice vs. Crown Molding, Explained

Cornice vs. crown molding is one of the most common mix-ups in architectural trim, and for good reason: the two words often describe overlapping things. A cornice is the projecting assembly that caps the top of a wall, most often on a building's exterior at the roofline. Crown molding is a single decorative profile that bridges the joint between an interior wall and the ceiling. This guide explains where each comes from, where each belongs on residential and commercial buildings, the materials used for them, and how to choose.

The short version: A cornice is the crowning assembly at the top of a wall or facade, inherited from the classical entablature, and it usually projects outward to throw shadow and shed water. Crown molding is one sprung profile installed where an interior wall meets the ceiling. Every crown is a kind of cornice in miniature, but not every cornice is a crown. Mouldex Composites makes exterior cornice moldings for rooflines and facades and plaster-finished interior crown moldings for rooms, lobbies and corridors.

What Is a Cornice?

The word comes from the Italian cornice, meaning a ledge. In classical architecture, the top of a wall or colonnade is the entablature, which has three horizontal bands: the architrave at the bottom (resting on the columns), the frieze in the middle (often plain or carved), and the cornice at the top. The cornice is the part that projects the furthest. On Greek and Roman temples, it protected the wall below by throwing rainwater clear of the face, and its deep overhang cast a strong shadow line that made the building read as finished.

A traditional cornice is built up from several parts:

• Bed molding: the lower profile that sits against the wall and supports the projection above.
• Corona: the flat, vertical face that projects outward, often with a drip edge on its underside.
• Cymatium: the curved top profile, usually an ogee or cove, which is where the idea of a "crown" comes from.
• Soffit: the underside of the projection, sometimes decorated with dentils or modillions.

On today's buildings, "cornice" most often means the exterior molding or assembly at the roofline, at the top of a parapet, or above a storefront. It also appears as a heavy head over windows and doors. In residential carpentry, roofline cornices are often grouped into three types: a box cornice (the rafter tails are enclosed with a fascia and soffit), an open cornice (the rafter tails stay exposed) and a close cornice (little or no overhang, with the molding tight to the wall).

An exterior cornice caps the facade and creates the deep shadow line that finishes a building.

Exterior cornices are installed with adhesive, which is usually enough on its own; mechanical fasteners are added depending on the weight of the piece. This installation video shows the process on brick, and the same approach applies to other wall surfaces:

What Is Crown Molding?

Crown molding is a decorative profile installed at the junction of an interior wall and ceiling. It is "sprung," meaning it sits at an angle across the corner with an open space behind it, rather than lying flat against either surface. The name comes from its position: it crowns the room the way a cornice crowns a building. In fact, interior crown descends directly from the cymatium at the top of the classical cornice, scaled down and brought indoors.

Crown molding does three things well. It hides the joint where the wall meets the ceiling, which is rarely perfectly straight. It adds a horizontal line that sets the proportion of a room. And it brings the architectural style of the building inside, from a simple cove in a contemporary condo to a layered ogee in a formal dining room or hotel ballroom.

You will also hear interior crown called "cornice," especially in the UK, Australia and in older North American plaster work, where a large, built-up ceiling molding is a cornice. That's why many suppliers, Mouldex included, use both words for interior profiles. A useful rule of thumb: a single sprung profile is crown; a larger, multi-part treatment at the ceiling, or anything at the exterior roofline, is a cornice.

Mouldex interior crown moldings have a lightweight EPS foam core with a smooth plaster finish. Profiles such as the Florence, with its classic ogee curve, and the Alston give generous scale without the layering that traditional wood crown needs, and many coordinate with a matching coffered beam. Here is how interior moldings go up:

Cornice vs. Crown Molding: Key Differences

Factor	Cornice	Crown molding
Where it goes	Top of an exterior wall, roofline, parapet, storefront or over openings; sometimes large interior ceilings	Interior wall-to-ceiling junction; also tops cabinets and built-in furniture
What it is	An assembly or a large profile that projects outward from the wall	A single sprung profile across the corner
Origin	The top band of the classical entablature	The cymatium, the top profile of the cornice, brought indoors
Main job	Shed water, cast shadow, cap the facade, cover the roof-wall joint	Hide the wall-ceiling joint, set room proportion, add decorative detail
Scale	Bold, read from the street or across a plaza	Proportioned to ceiling height and room size
Exposure	Weather, UV and freeze-thaw cycles	Indoor conditions

The simplest way to remember it: if it faces the weather or tops a facade, it is a cornice. If it sits in the corner of a room, it is crown molding.

Where Each Is Used

Cornices on homes and commercial buildings

On a custom home, a cornice at the eaves or along a parapet gives a stucco or brick facade a finished top edge, and a smaller cornice above the front door or garage adds presence where people look first. Pair it with a band molding lower on the wall and the facade gains a clear base, middle and top. Read more about that line in The Line That Ties a Facade Together: Belly Bands and Belt Courses.

On commercial buildings, the cornice does even more work. Multi-family and mixed-use buildings use a heavier cornice at the top floor to cap a long elevation. Hotels and restaurants use them over entrances and along the street face. Retail storefronts use a cornice to frame the sign band, and offices and institutional buildings use them to bring classical proportion to otherwise plain facades. In historic commercial districts, replacement cornices are a standard part of facade restoration. Profiles with a deep projection, like the Portland (5.5 in deep), create a dramatic overhang, while tighter profiles like the Augusta suit window heads and smaller elevations. For more on rooflines, see Exterior Crown Molding: Styles, Sizes and Materials for Rooflines and Facades.

Crown molding in homes, hotels and offices

In homes, crown is the finishing touch in living rooms, dining rooms, primary bedrooms and kitchens, and it's one of the easiest ways to add character in a renovation. In hotels, crown runs through suites, corridors and lobbies, where the same profile has to look identical from floor to floor. Restaurants and office lobbies use larger profiles to make tall ceilings feel intentional. For a broader look at interior options, read Crown, Cove or Coffered? Choosing Plaster Mouldings for Every Room.

Materials: Then and Now

Classical cornices were carved stone or terracotta. Later builders used wood, run plaster and, in the 1800s, pressed sheet metal for commercial storefronts. Interior crown was traditionally wood or plaster, run in place or cast in sections. Today, the main choices are:

• Wood and MDF: familiar for interior crown, but wood can rot or warp outdoors, and large profiles need several pieces stacked together.
• Precast concrete and stone: durable and authentic, but very heavy, which means structural support and often cranes.
• PVC and polyurethane: light and easy to handle, with different looks and movement characteristics.
• Cement-coated foam (Mouldex exterior): an EPS foam core with a cement-based coating about 3/16 in thick, reinforced with fiberglass mesh. It is moisture-inert, won't rot or warp, and has the look of precast stone at a fraction of the weight.
• Plaster-finished foam (Mouldex interior): an EPS foam core with a smooth plaster finish, less susceptible to cracking than traditional run plaster and light to handle at ceiling height.

For cornices especially, weight matters. Mouldex is much lighter than precast and costs less once material and labor are counted. Primer is required on all Mouldex moldings: exterior cornices are finished with an exterior latex or a textured brush coat, and interior crown is primed and painted after installation. Trim is cut and mitered on site and sold by the piece. For commercial projects, fire-rated options are available on request with a Class A fire rating (flame spread 25, smoke developed 110) that helps meet ASTM E-84 and UL 263, and CAD details and specifications are available to trade partners through our Trade Program. Lead times are typically 7 to 10 days depending on profile and quantity. For a deeper material comparison, read Exterior Moulding Materials Compared.

Combining Cornice, Crown and Other Decorative Elements

The most convincing buildings use both and tie them together, so the elegance of the facade carries into the rooms. A Georgian-style home might carry a dentil cornice at the eaves and a matching ogee crown in the front hall. A boutique hotel might use a bold cornice on the street facade and a quieter crown in the guest rooms, with a light cove in the lobby (see how a cove turns crown molding into a light source). Inside, crown can extend into coffered ceiling beams with a matching profile, so the ceiling reads as one design. When a stock profile doesn't match an existing building, custom profiles are available, which is especially useful for restoration work.

Frequently Asked Questions

Finishing the top of a wall? Browse exterior cornice moldings or interior crown moldings, request a quote or order a free sample kit.