The detailing referred to in connection with the handling of doors is one of the most important factors in interior design. Every architectural component must be detailed well. Poor details make for poor design. The meaning of detailing in a design sense is more than the graphic explanation of certain components on a drawing. It means the way materials are put together, the way one part is fastened to another, the way parts and materials are expressed and articulated. Stairs or ramps are architectural components of great importance, whether in stores, in public buildings, or in homes. Since these structural features represent large vertical forms in space, they often become the dominant design feature in an interior space (see photograph). Stairs in hotel lobbies, for example, are usually in very prominent locations. The actual stair design, however, is surprisingly restrictive and set. The height of riser and its relation to the tread is fixed, and variations for normal vertical circulation are extremely limited. Matters of detail involve such considerations as whether the stair is open or enclosed, whether it is a bold sculptural form or an airy dynamic shape (resulting from the use of open treads without risers), whether the stair honestly expresses its material (be it wood, steel, or marble), or is wrapped in carpeting. The many detailing possibilities present a real challenge to designers and, unlike mass-produced windows, light switches, or plumbing fixtures, give designers a chance to design in a completely personal or creative way.

Components such as heating units, electric outlets and switches, and telephone connections offer no design choice other than the limited selection among mass-produced products and the best placement within the space. The pattern created by the placement of fixtures is as important with walls or any other surfaces as it is for ceilings. A given wall may have doors, windows, electric outlets, switches, air-conditioning registers, and heating units (radiators or convectors). It is the designer’s job to deal with all of these components by design, by organization, by placement or elimination, and by detailing. Often, the more bulky components, such as radiators, can be “eliminated” by building the unit into the wall or, in existing, poorly detailed buildings, by creating a “built-in” appearance through the inclusion of some design feature. Radiators or convectors are often housed in neatly detailed enclosures that may run the whole length of a window wall and may at the same time provide an additional surface under the windowsill. Depending on the location, a continuous enclosure may contain some shelving or storage elements, thus making use of the extra space not needed for the actual heating unit (or air-conditioning unit).

In large, nonresidential interiors, the mechanical components are often massive. For instance, the telephone installation needed in an office for several hundred people requires a very large space and a complex installation of conduits and other elements that affect the interior design. The air-conditioning or heating unit for a simple store may be fairly bulky, and again the designer deals with the allocation of space as well as with the mechanical function of the equipment. All of the mechanical equipment for buildings is specified or engineered by specialists, but it is essential that an interior designer have the basic knowledge and understanding to be able to coordinate the various specialties. The many pipes, stacks, and vents that go into a plumbing system, although not exposed and shown as a rule, are of real concern to the designer. Whether architectural components are expressed and detailed, whether they are concealed or built-in, they are incorporated in the design.

Furniture and accessories

To the layman, furniture is the most important aspect of interior design. It is a significant component of design to the professional as well, since it is the most personal and intimate product relating man to a building. It is also personal because it can be moved from one home to the next and handed on from generation to generation, and often furniture takes on important sentimental value. Accessories are even more personal, but they are less significant to the overall effect of the interior, since they are by nature smaller than furniture. Almost anything that people own or collect could be called an “accessory,” including functional objects, such as ashtrays, and decorative objects, such as porcelain, glass, or ceramics.

Although some quite sophisticated furniture existed in ancient Egypt, the use of furniture was rare during the Middle Ages and only became significant in the West during the Renaissance. During most subsequent periods there have usually been close interrelations between architectural and furniture styles and modes of interior design. The 20th-century pioneers of design and architecture—such as Mies van der Rohe, Le Corbusier, and Marcel Breuer—were not able to find any suitable contemporary furniture available in the 1920s and 1930s when they built structures without historical references. They designed much of their own furniture, and some of these modern “classics” are still very much in demand. Well-designed modern furniture developed in Scandinavian countries in the 20th century out of the long tradition of craftsmanship and design prevalent in those countries. The real beginning of modern furniture design in the United States came only after World War II, and much of it was first developed for nonresidential uses. Charles and Ray Eames, George Nelson, and Florence Knoll are among the distinguished American designers who have pioneered furniture design and manufacturing processes. Their furniture primarily was introduced to the public through use in public or work spaces. A large segment of furniture manufacturers, however, has still not been touched by design of any kind, and furniture under such invented names as “Mediterranean” or “Italian Provincial” (both nonexistent historic styles) is still being foisted upon the public.

Whatever material or manufacturing process may be used, the important criteria that must be applied in furniture are function, comfort, and durability, together with aesthetic considerations. Architects and interior designers often prefer to build in furniture wherever possible, and, indeed, some of the best historic and contemporary interiors contain little movable furniture. An interior without any furniture or accessories would probably appear stark and uninviting, and it is clear that the personal touches possible through selection of appropriate furniture and accessories are very important.

One can use a vast array of decorative objects or plants as accessories. In a way, every accessory used in a home, office, or public space is in some way a part of the total composition, and must therefore be selected with care. No rules exist on what is “proper” other than the basic principles of design that were discussed earlier.