Types of Ornamental & Decorative Plaster

Ornamental plaster adds beauty and splendor to any space. Often cast, but sometimes run in-situ, ornamental plaster finishes have been popular across many different architectural movements. Often there is carryover been types of ornamentation and themes seen within the finished designs. Prior to the advancement of millwork technology, plaster was the only feasible means by which people could enrich their interior and exterior spaces. Colonial homes (in the Adams, federalist, and Georgian styles) have a specific palette of plaster techniques including crown molding, raised wall paneling, rounded corner detailing, chair rail, and base rail. Additional accenting was common around fireplaces, important doorways, and chandeliers. Second Empire and beaux-arts often required similar moldings, but on a much larger and far more complex scale. Here are some of the most common types and applications of ornamental plaster across a spectrum of building styles.
Arches
Often built to breakup long hallways, act as a means of joining rooms without adding doors, or as a way of hiding unsightly structural supports. The most common type of arch is a keystone arch, reminiscent of how arches were built in ancient times. The large “center stone” mimics the once crucial keystone, which held all the other stones in the arch in place. Depending on the stylistic movement of the space, the interior of the arch may be coffered, or flat. Additional ornamentation, such as a relief may surround the arch or cornices at the base might be added.

Arches at St. Mary's Church located in Willimantic, Connecticut
Chair rail
Much like it sounds, a chair rail is a plaster band at chair height that surrounds a space—most commonly found in the dining room. While it can be highly embellished, it is often found in its simplest forms as a bullnose or rectangular molding. Though it adds decorative interest to a space, it serves a highly functional purpose—prevent the back of a wood chair from damaging plaster walls.
Columns
Splendid in nature, columns can transform as space, especially one with high ceilings or when a space is open to the floor(s) above. A basic column is comprised of three parts: a plinth, shaft, and capital (ascending order). Five main classically based columns are prevalent throughout revival and colonial architecture: Doric, Ionic, Corinthian, Tuscan, and composition. These five styles evoke differing levels of visual interest, with Doric being among the more simplistic and Corinthian being more complex. Often, changes to the capital are common in Corinthian columns to depict local flora—southern plantations often use tobacco leaves and complex scrolling in lieu of acanthus leaves, the traditional ancient Greek floral depiction. Other variations include gilding. The shaft of can also vary, including simple polished plaster, marbleizing, or fluting. The base of columns are often square, though some are rounded: Doric columns are the exception, as they have no base by design.

Columns at the National Building Museum located in Washington, D.C.
Cornices
Horizontal moldings of basic or repeating pattern, most commonly referred to as “crown molding.” Cornices also appear atop doorways, windows, furniture, built-in fixtures, and other prominent areas within a space. Common varieties include dentil, beveled, rounded, stepped, and elongated variations on the aforementioned styles. Carved reliefs are not uncommon, and can feature leaves, animals, and themes relevant to the architectural movement. Large plaster cornices also surround doorways and windows, enlarging their presence within the room. Simple cornices are usually crafted by applying wet plaster into a form and running a specially shaped “knife” that creates a finished molding pattern.

Cornice Molding at the Maryland State House located in Annapolis, Maryland
Domes
The concave surfaces of domes do not have to be large in surface area to create a lasting effect. Often not deep, domed shapes served as a way of drawing the eye ever higher within a room. Typically centered with in a larger space or reproduced in tandem miniature in a space such as a hallway, domes are a popular choice with architects looking to create Greco-Roman revival space. The interior of the dome can be finished in many ways—flat paint, mural (Apotheosis of Washington, US Capitol building), gold leaf/Dutch metal, or scalloped with plaster.
Fireplace surrounds
Traditionally the focal point of the room, fireplaces are not only dressed-up with large ornate mantels but also feature decorative plaster work designed to draw the eye towards the fireplace and frame it. Common embellishments include faux columns (pilasters), reliefs on either side, accentuating molding abutting the mantel, and plaster ornamentation/frieze directly above the fireplace.
Medallions
Commonly found on ceilings near the base of a chandelier or on walls centered in a space or at the base of a sconce, medallions come in a variety of shapes and sizes. Ceiling medallions can be free standing throughout a space but are commonly symmetrically arranged within a defined area. Chandelier medallions are quite prevalent are often plain, round beveled, scalloped, depicting a blooming flower, geometric, or evoke elements of a moldings/frieze elsewhere in the space.

Medallion work found at the Shrine of Our Lady Guadalupe Church located in La Crosse, Wisconsin
Pilasters
Tasked with drawing the eye upward, pilasters are commonly found in large, open spaces with high ceilings. Though not structurally significant on their own, they do important work in accentuating the scale of the overall space. These faux column moldings often directly evoke specific column styles or can directly mimic columns found elsewhere within the space. Most commonly, these are Ionic or Corinthian columns.

Pilasters at the Shrine of Our Lady Guadalupe Church located in La Crosse, Wisconsin
Skirting
Sometimes referred to as baseboard, this molding us found where the wall meets the floor. Unlike many other decorative plasters, skirting is usually pretty simple and often only has a few beveled features (if any) and can vary in height. Marbleizing can be done to accentuate the floor or walls.
Plaster is a highly versatile building material and a skilled plaster can create truly remarkable moldings. Though time, water damage, etc., can ruin plasterwork, modern technology and time-honored craftsmanship can revive lost or damaged plaster molding, restoring grandeur to a space.
If you are in need of plaster restoration or repair services, please contact John Canning & Co.