Although trim fashions have changed throughout the years, exterior door and window trim is still used frequently to add variation to the front of a house or to match with other exterior features. Exterior trim could also be installed to give your house a historical look. With so many combinations of types, materials and styles of trim, make a list of your design preferences, budget and maintenance needs and research your options before deciding.
Wood, although at one point one of the only available options for exterior trim, is becoming less popular with the declining price of synthetic materials. Non-exotic varieties are cheaper than many other materials, however, is generally easy to work with and is simple to install. It can be painted any colour or stained for a natural look. Certain types of wood work best as exterior trim, as well as many processes available to pressure-treat and seal the wood, to prevent swelling and rotting. Still, wood exterior trim is not impervious to the effects of the weather, and rotting or warping may still occur, making frequent repairs or reinstallation necessary.
Because of its durability and low installation cost, plastic trim is another popular type of exterior window or door trim. Plastic trim is mostly manufactured from high-density polyurethane but is often made of PVC material as well. There are many benefits of plastic as a material for exterior trim, the primary advantage being that it doesn't rot or warp as wood does. Although plastic trim can simulate wood in many ways, some natural elements of wood---such as rough-cut cedar and many types of wood stains---cannot be replicated on plastic. For many homeowners, though, the long life and low maintenance requirements of plastic exterior trim offsets any cosmetic deficiencies.
Several different types of exterior trim have been formulated specifically for durability and easy installation. For example, AZEK, a cellular PVC material, is waterproof, completely insect-resistant and requires minimum cleaning. AZEK can be shaped, mitred and routed just like wood, but doesn't splinter and doesn't require stains or paint. Another synthetic trim material, DuraBoard, can be shaped, cut and nailed similar to wood, but does not have the problems that often accompany wood exterior trim, such as cracking, rotting and moisture absorption. Although many of these new synthetic products have higher material costs than wood or plastic, the price is dropping as the availability of these materials continues to rise.
Besides synthetically manufactured materials, exterior door or window trim can also reflect any stone, brick or stucco materials from which a house is constructed. However, the installation of these materials usually requires special machinery and trained contractors.
Because exterior trim gained in popularity during the Renaissance and Baroque eras, trim that is heavily carved with scroll work and flowered patterns has become an enduring style. Exterior trim carved with nature designs or even small figures and scenes look great on houses with columns or other architectural accents reminiscent of Greek architecture. Exterior trim with Victorian styling, from the late 1800s and early 1900s, is also usually very ornate and highly embellished. Queen Anne-style homes often feature decorative window and door trims.
Beginning in the 1920s, popular architecture began to move away from the more ornamental trends toward an increasingly minimalistic aesthetic ideal. With the advent of improved engineering and construction technology, buildings often contained large, open spaces and extensively used glass and unpainted metal. Because of these more streamlined architectural trends, the popularity of exterior---and even interior---trim fell drastically. The styles of trim that remained in use, usually found in residential settings, also became more minimalistic in accordance with the general movement. Smooth, unadorned trim replaced the bevelled and shaped trim styles of the Victorian age. Eventually, the two styles blended somewhat to create the exterior trim styles that are common on many new homes today: white or off-white in colour, rather than the dark wood and gold gilt that had been popular previously, with clean and relatively simple bevelling.