Architectural details fascinate me. Looking up at various historical buildings in and around the Hudson Valley, I always find myself noticing structures topped with decorative cornices.
Cornices date from classical Greek architecture and historically have served both functional and decorative purposes. On the functional side, cornices typically are basic horizontal structures designed to funnel rainwater away from a building’s walls and can be as simple as a straight, projecting ledge that caps the top edge of a wall; the term “cornice” actually is derived from the Italian word for ledge.
On the decorative side, however, cornices can be elaborate ornamental structures that add dignity and character to a building. Decorative cornices give a visual break to a building and serve as a counterweight between the lower and thicker sections of a wall and the narrower rooftop edge. Cornices often are enhanced with crown moulding and styles can range from modest dentil mouldings to more complex carved scallops, scrolls, or spirals.
There are three main types of cornices used in residential construction: box cornice, open cornice, and closed cornice. In narrow box cornices of 12 inches or less, the soffit board is nailed directly to the bottom side of the roof rafters; wider box cornices typically will require additional support members, called lookouts, which provide a nailing base for the soffit. Open cornices typically are used in more contemporary and rustic designs, and leave the undersides of the rafters and roof exposed. Closed cornices are used in cases where the rafters do not project beyond the wall; the bottom of the roof overhang is closed off and finished with a straight board called a frieze, and also can be embellished with moulding.
Although in the past, cornices were hand-crafted on site, today there are a wide variety of pre-fabricated solutions available that can save time and money, and are well within the reach of the savvy do-it-yourselfer. Typical pre-fabricated cornice materials include plywood, fiberboard, metal, fiberglass and polyurethane foam. These systems are sold in standard widths, ranging from 12 to 48 inches, and standard lengths ranging from 8 to 12 feet.
Pre-fabricated cornice sections typically are factory-primed and can be finished in a wide variety of treatments, including exterior paint, gel-coat, faux stone, faux metallic, and other attractive coatings. Complementary pre-finished soffit and finishing trim kits also are available to create a uniform appearance on a building’s exterior. There are also many custom options available, including cast stone, aluminum and wood, although these are typically more expensive.
Cornices can add value and help protect a building from the debilitating effects of rainwater, snow, and ice. A variety of both basic and embellished designs are available to suit myriad architectural styles and budgets. And the one thing all cornices have in common is that they draw the eye and finish a structure in an aesthetically pleasing fashion—a trait that fans of both new and old construction can appreciate.
For more on architectural details and history, consider: