Exterior Cornice Molding: Types, Sizes and How to Choose
Exterior cornice molding is the projecting trim that crowns the top of a wall, where it meets the roof, the soffit or the top of a parapet. A well-chosen cornice gives a facade a finished top edge, casts a strong shadow line and helps shed rainwater away from the wall below. How to choose exterior cornice molding comes down to four decisions: the type of cornice (box, open or parapet), the profile, the size relative to the building, and the material.
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This guide covers each of those decisions for homes and commercial buildings across the USA and Canada: cornice vs crown molding, cornice types and profiles, sizing to the roofline, parapet or building height, and how cement-coated foam trim compares with precast, GFRC, fiberglass, wood, PVC and polyurethane. It finishes with where cornices are used, installation on stucco, EIFS and brick, and finishing.
It is written for homeowners planning a renovation, custom builders, stucco and masonry contractors, and architects working on multi-family, hotel, retail and office projects. If you want a shorter introduction to styles, read our post on exterior crown molding styles, sizes and materials.
Short answer: to choose exterior cornice molding, pick a cornice type that suits the roof (box, open or parapet), a profile that suits the architectural style, and a size that reads correctly from the street, usually larger than you expect. For most stucco, EIFS and masonry buildings, cement-coated EPS foam cornice molding is the practical choice: it won't rot or warp, and it is much lighter than precast and costs less once material and labor are counted. Browse the exterior cornice moldings collection to compare profiles.
What Is an Exterior Cornice?
In classical architecture, the cornice is the top layer of the entablature, the horizontal band that sits above columns. Below it are the frieze and the architrave. On today's buildings the term is used more loosely: an exterior cornice is any projecting molding or assembly that finishes the top of an exterior wall at the roofline, the eave or the parapet.
A cornice does two jobs. Visually, it caps the building and adds depth. Practically, its projection throws rainwater off the face of the wall and protects the joint between the wall and the roof structure.
Cornice vs crown molding
The terms overlap. Crown molding usually means a single sloped or curved profile at the top of a wall, indoors or out. A cornice is the complete crowning assembly, which may combine a crown with a fascia, a bed molding, a frieze band or dentils. In practice, one deep exterior cornice molding often does the work that once took several layered pieces of wood or stone.
Bed molding
The lower, supporting profile that meets the wall. It eases the transition from the flat facade into the projection above.
Corona or fascia
The flat, vertical face in the middle of the cornice. It creates the deep shadow line and carries the main projection.
Crown (cymatium)
The curved top profile, usually an ogee or cove, that finishes the assembly and helps shed water.
Types of Exterior Cornices and Cornice Profiles
Cornices are grouped by how they meet the roof (type) and by the shape of the molding (profile).
Cornice types
- Box cornice (closed cornice): the rafter tails are enclosed with a fascia and soffit, and a molding finishes the top of the wall beneath the soffit. The most common type on houses.
- Open cornice: the rafters are left exposed under the eave, as on Craftsman and rustic designs. A smaller molding or frieze band may still finish the top of the wall between the rafters.
- Parapet cornice: on flat-roofed buildings, the cornice is mounted at or near the top of the parapet wall. Standard on storefronts, apartment buildings, hotels and offices.
- Raking cornice: a cornice that follows the slope of a gable or pediment, often paired with a horizontal cornice to form a triangular pediment.
Cornice profiles
- Ogee and S-curve: the classic double curve seen on Georgian, Colonial, Mediterranean and traditional commercial facades.
- Cove: a concave curve that reads softer and suits transitional designs and soffit transitions.
- Stepped and flat-faced: crisp fillets and flat fascias with little or no curve, suited to modern and contemporary architecture.
- Dentil and bracketed: traditional cornices with repeating blocks or brackets beneath the crown. At Mouldex, brackets are a specialty order.
Mouldex currently offers 20 standard exterior cornice profiles, from 3-1/2 inch to 18 inch sizes. Every profile can also be custom modified, and custom profiles (each with its own custom spec code, MSC) can be made to match an existing or historic cornice.
3-1/2 in, S-curve
Buckingham
A refined S-curve with about 3-1/8 inches of projection. Suits window heads, porches and smaller residential rooflines.
7 in, deep projection
Portland
About 5-1/2 inches of projection for a strong overhang and shadow line. A good fit for one- and two-story rooflines.
10-1/2 in, large S-curve
Sophia
A smooth, large-scale curve with about 4-1/2 inches of projection, for traditional, Colonial and Mediterranean facades.
12-1/2 in, oversized curve
Loma
An oversized S-curve with nearly 5-3/4 inches of projection, built for larger homes and commercial facades.
For modern buildings, the Tuxedo (14 inch) uses stepped fillets and a flat fascia instead of a curve, and works well at tight soffit transitions.
How to Size Cornice Molding to the Roofline, Parapet and Building Height
The most common cornice mistake is going too small. An exterior cornice is seen from the street, often one to several stories below, so a profile that looks generous in your hand can almost disappear on a tall wall. Interior crown sizes are not a useful guide outside.
Five sizing principles
- Scale to wall height and viewing distance. The taller the wall and the farther away people view it, the larger the cornice needs to be to read clearly.
- Look at projection, not just height. Projection (how far the molding sticks out from the wall) creates the shadow line. Two profiles of similar height can look very different if one projects twice as far.
- Respect the soffit and eave. On a box cornice, the molding has to fit the space between the top of the wall and the soffit. A flatter, stepped profile can help where that space is tight.
- Size parapet cornices to the whole facade. On flat-roofed buildings the cornice is often the dominant horizontal line, so it can carry a much larger profile than a residential eave.
- Keep the hierarchy. The main cornice should be the largest horizontal element. Window head cornices and band moldings at floor lines should step down in size so the facade reads in order.
Size bands as a starting point
| Size band | Typical location | Example Mouldex profiles | Notes |
|---|---|---|---|
| 3-1/2 to 6 in | Window heads, door surrounds, porches, single-story accents | Augusta, Buckingham, Corso, Dovercourt | Reads well at close range; can disappear on a tall wall. |
| 6 to 9-1/2 in | One- and two-story residential rooflines, storefront caps | Portland, Rosedale, Goulding, Stephanie | The most versatile range for houses and low-rise commercial. |
| 10 to 14 in | Two- and three-story homes, multi-family, hotels | Sophia, Julius, Loma, Tuxedo | Strong presence from the street; check soffit clearance. |
| 16 to 18 in | Commercial parapets, mid-rise and large facades | Glen Ridge, Norton | Statement profiles; larger still is possible as a custom profile or a built-up assembly. |
These bands are a starting point, not a rule; style and the other trim on the facade matter too. When in doubt, hold a sample or a short length up at the cornice line and view it from the street before ordering. CAD details and specifications for any standard profile are available to trade partners through our Trade Program.
Exterior Cornice Materials Compared
Each cornice material has a place. Here is a fair comparison for exterior use.
| Criterion | Cement-Coated EPS Foam | Precast / GFRC | Fiberglass (FRP) | Wood | PVC / Polyurethane |
|---|---|---|---|---|---|
| Weight | Much lighter than precast; most profiles are installed by hand. | Very heavy (GFRC less so than solid precast); often needs lifting equipment and engineered anchors. | Light. | Moderate; large built-up cornices get heavy. | Light. |
| Rot and moisture | Moisture-inert core; won't rot or warp. | Won't rot; unsealed joints can take on water. | Won't rot. | Prone to rot at joints and end grain; needs regular painting. | Won't rot; PVC moves with temperature. |
| Cracking and movement | Less susceptible to cracking than rigid materials when joints are detailed correctly. | Rigid; can crack under differential movement. | Stable; seams need careful finishing. | Splits and checks over time. | Thermal expansion can open joints on long runs. |
| Fit with stucco and EIFS | Excellent; stucco trades tie it into the wall with familiar basecoat and mesh. | Good, but adds heavy load to the wall. | Fair; usually fastened and caulked as a separate component. | Fair; must be kept separate from stucco to avoid trapped moisture. | Fair; needs expansion allowances at transitions. |
| Cost (material plus labor) | Less than precast once material and labor are counted. | Highest, plus equipment and anchoring. | Mid to high, depending on size and detail. | Low up front; ongoing upkeep. | Mid-range for stock profiles. |
| Design flexibility | Wide range of standard profiles, custom profiles and arches. | Very high detail at high cost. | Good for large ornate pieces; custom molds add cost. | Good for traditional millwork. | Good for stock ornamental profiles. |
| Best suited to | Stucco, EIFS and masonry homes, multi-family, hotels, retail and renovation. | Monumental and high-end traditional buildings. | Large ornate cornices and some commercial work. | Heritage restoration where real wood is required. | Budget residential and wood-sided homes. |
Mouldex cornice moldings have an EPS foam core conforming to ASTM C578 Type I for exterior use, with a cement-based coating about 3/16 inch thick, reinforced with fiberglass mesh. The finished surface looks and feels like stone or stucco. A fair caveat: foam cornice is not a paint-free product. It must be primed and finished after installation, and its sealant joints need the same periodic care as the rest of the facade. Mouldex products are backed by a warranty; ask for the terms that apply to your project.
If you are comparing cornices with window surrounds on the same building, our guide to the best exterior window trim for stucco homes covers those materials in more depth.
Where Exterior Cornice Molding Is Used
Cornices are not only for rooflines. The same profiles appear at several levels of residential and commercial facades, and repeating one profile family across them makes a building look designed rather than assembled.
On larger projects, cornices usually work alongside exterior band molding at floor lines and window trim at each opening, so the horizontal lines step down in size from the roof to the ground floor.
Rooflines and eaves
The classic location on custom homes and renovations, finishing the top of the wall beneath the soffit on a box cornice.
Parapets
A cornice caps the parapet on flat-roofed buildings and gives the facade a strong, finished top edge.
Window and door heads
A smaller cornice above a window or entry surround creates a traditional head detail and helps shed water off the opening.
Storefronts and commercial facades
Retail, restaurant and office buildings use cornices above signage bands and at the parapet to define the storefront.
Multi-family and mixed-use
Apartment and condo buildings repeat one cornice profile across long elevations, where light weight and fast installation keep schedules on track.
Hotels and institutional
Hotels, resorts, schools and civic buildings use deeper cornices at the entry and roofline, with simpler profiles on upper floors to control cost.
For commercial projects with code requirements, 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. Confirm what your construction type requires with your design team before ordering.
Installing Exterior Cornice Molding on Stucco, EIFS and Brick
This is an overview, not an installation manual. Follow the Mouldex installation guidelines and the wall system details, and use an experienced installer.
Steps common to every wall
- Confirm the line and the substrate. Snap a level line and check that the wall is sound, clean and flat.
- Cut and miter on site. Cornice is sold by the piece, cut to length and mitered at the corners on site, so every run fits the actual building.
- Adhere and fasten. Bond the cornice to the wall with a compatible exterior adhesive, adding mechanical fasteners where the guidelines and the wall system call for them, particularly on larger profiles.
- Seal the joints and the top edge. Seal butt joints, miters and the top edge so water sheds outward and cannot get behind the cornice. Deep projecting cornices benefit from a flashing or sloped cap on top.
- Prime and finish. Primer is required before the finish coat (see below).
On stucco
Cement-coated foam cornice works naturally with stucco. It can be bonded to the stucco, and the joint between cornice and wall is tied in with basecoat and mesh by the stucco crew, so the cornice reads as part of the wall.
On EIFS
On EIFS, the cornice is usually integrated with the base coat and mesh of the system. Detailing must keep the drainage path and weather barrier intact, so follow the EIFS manufacturer's details for attachments and terminations, and coordinate with the EIFS applicator before work starts.
On brick and masonry
On brick, block or stone veneer, the cornice is bonded to clean, sound masonry with a compatible adhesive and mechanically anchored into the masonry. Seal the top edge carefully, since water running down a brick wall will find any open joint behind the cornice.
Finishing and Caring for Foam Cornice Molding
Primer is required on all Mouldex moldings. After priming, finish the cornice with an exterior latex paint or a textured brush coat. A textured finish matched to the stucco makes the cornice look carved from the wall; a smooth latex finish gives a crisper, painted-trim look.
- Match or contrast: a cornice painted the same color as the wall gives a quiet, monolithic facade; a lighter or darker shade emphasizes the roofline.
- Lighter colors absorb less heat on sunny elevations.
- Routine care: wash gently with mild detergent, and inspect the paint and sealant joints periodically, as you would the rest of the facade. Repaint when the finish shows wear.
Mouldex lead times are typically 7 to 10 days, depending on the profile and quantity, and quotes usually come back within 24 hours (longer when a full take-off is needed). To see and feel the material before you choose, order free sample kits, then send your elevations through Request a Quote.
Frequently Asked Questions
What is cornice molding?
Cornice molding is a projecting molding that crowns the top of a wall. Outside, it finishes the roofline, eave or parapet, adds a shadow line and helps throw rainwater clear of the wall below. Inside, the same term is often used for large crown molding at the ceiling.
What is the difference between a cornice and crown molding?
Crown molding is usually a single sloped or curved profile at the top of a wall. A cornice is the complete crowning assembly, which can include a crown, a fascia, a bed molding and other details. On many modern buildings, one deep exterior cornice molding does the job of a full cornice assembly.
What are the main types of cornices?
The three most common exterior types are the box (closed) cornice, where the rafter tails are enclosed by a fascia and soffit; the open cornice, where the rafter tails are left exposed; and the parapet cornice on flat-roofed buildings. A raking cornice follows the slope of a gable or pediment.
How big should an exterior cornice be?
Larger than you would use indoors. Scale it to the wall height and viewing distance: roughly 6 to 9-1/2 inch profiles suit one- and two-story rooflines, 10 to 14 inch profiles suit taller homes, multi-family and hotels, and 16 inch and larger profiles suit commercial parapets. Hold up a sample at the cornice line and view it from the street before ordering.
Can you use crown molding outside?
Only if it is made for exterior use. Interior crown, including plaster-finished foam crown, is not designed for weather. Exterior cornice molding such as Mouldex cement-coated EPS foam is made for outdoor exposure, and it must be primed and finished after installation.
Can Mouldex make a custom cornice profile?
Yes. Any standard profile can be modified or shaped into arches, and Mouldex can make custom profiles, each with its own custom spec code (MSC), to match an existing or historic cornice from a drawing, photo or sample. Send the details through Request a Quote; quotes usually come back within 24 hours.
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