Cornice

Cornice is one of the most ancient architectural elements, present in Greek and Roman temples 2,500 years ago and continuously used since. The word comes from the Italian "cornice," meaning "ledge," and that's essentially what a cornice does: provides a horizontal projecting ledge at the top of a wall or structure. In classical architecture, cornices were exterior elements crowning buildings; in residential interior design, the term often overlaps with crown molding (the interior trim at the ceiling), but cornice can also refer to more substantial decorative elements and to window treatments.

Cornice in classical architecture

In classical Greek and Roman architecture, the cornice is the uppermost element of the entablature (the horizontal section between columns and roof):

• Entablature = architrave (bottom) + frieze (middle) + cornice (top)
• Cornice projects outward dramatically to throw rainwater clear of the wall below
• Always decorated with classical motifs (dentils, modillions, brackets)
• The proportions of the cornice are dictated by classical orders (Doric, Ionic, Corinthian, Tuscan)

This classical exterior cornice became the model for interior cornice and crown molding in Western architecture.

Cornice vs crown molding, terminology distinction

These terms are often used interchangeably but technically differ:

• Cornice, broader term; can refer to any projecting horizontal molding at the top of a wall, building, or piece of furniture; can be very substantial and ornate
• Crown molding, specific interior trim where wall meets ceiling; typically smaller than ornate cornices

In contemporary American residential context, the terms are often used interchangeably for the ceiling-line trim. In historic and classical architecture contexts, cornice refers to more substantial decorative elements.

Types of interior cornices

• Built-up cornice, multiple pieces of molding combined to create substantial decorative profile
• Plaster cornice, traditional ornate plaster-cast cornice; common in historic European homes
• Wood cornice, solid wood; can be stained or painted
• Polyurethane / foam cornice, modern affordable substitute for ornate plaster; very lightweight
• Box cornice, boxed-in structural element that hides utilities at ceiling line

Cornice in different architectural styles

• Greek Revival, substantial classical cornice with dentil and frieze details
• Georgian, elaborate plaster cornice with classical motifs
• Victorian, extremely ornate plaster cornices with elaborate moldings
• Edwardian, slightly more restrained but still substantial cornices
• Federal / Adam style, refined cornices with neoclassical motifs
• Modern (early 20th century onward), cornices significantly simplified or eliminated
• Contemporary minimalist, typically no cornice; ceiling-wall transition is a clean line

Window cornice / cornice board

A separate use of "cornice" in residential design refers to window treatments:

• A "window cornice" or "cornice board" is a decorative wood or fabric-covered box mounted above a window
• Hides curtain rods and hardware
• Adds architectural detail to windows that lack substantial trim
• Can be upholstered, painted, or decoratively detailed
• Common in traditional and Hollywood Regency interiors
• Different from a valance (fabric-only) or pelmet (similar function, slightly different construction)

Modern interior approach

Contemporary residential design typically simplifies the cornice question:

• Modern flat-ceiling rooms, no cornice; clean wall-to-ceiling transition
• Modern with crown molding, simple crown molding (5-7" tall) as restrained cornice substitute
• Modern Mediterranean / Belgian, sometimes substantial plaster cornices for traditional feel
• Restoration / period homes, full restoration of period-appropriate cornices

Common mistakes

The biggest cornice mistake is using ornate Victorian-style cornices in homes with otherwise modern architecture, the disconnect reads as added rather than integrated. The second is poor scale; cornices that are too small for the room's ceiling height look insignificant, while overscale cornices in small rooms overwhelm. The third is poor installation; cornices amplify any installation imperfections (visible seams, uneven miter cuts) because they sit at eye level.

Cost

• Simple polyurethane cornice, $3-15 per linear foot installed
• Stained or painted wood cornice, $8-25 per linear foot installed
• Plaster cornice (ornate), $25-100+ per linear foot installed
• Custom restoration cornice (historic homes), $50-300+ per linear foot
• Built-up cornice (multiple molding pieces combined), $20-60 per linear foot installed

Related architectural details

Cornice is part of a vocabulary of horizontal trim including crown molding (often synonymous in interior context), frieze (the decorative band below the cornice in classical architecture), chair rail (mid-wall horizontal), and picture rail (separate horizontal for hanging art). It also includes vertical trim like pilasters and casings that often interact with cornices at corners.