The elements of classical architecture, which we inherited from the ancient Greeks, have been in constant use and continual evolution for over 2000 years. They consist of the various columns, along with their bases and capitals, beams, and decorative moldings. These elements are used in harmony with one another and their use is governed by rules of proportion and specifics of ornamental detail. These are referred to as “the classical orders of architecture.” It is generally accepted that there are five such orders that have been classified since the Renaissance: Tuscan, Doric, Ionic, Corinthian, and Composite (a combination of Corinthian and Ionic).
Through most of the life of Architectural Graphic Standards since its first edition in 1932, there had been no specific section of details of the orders until 1988, when the eighth edition of Graphic Standards published a two‐page spread. This was then expanded in the ninth edition (1994) to six pages and so it remained in the tenth edition. Given the underlying technical‐, detail‐oriented focus of Architectural Graphic Standards it may not have been seen as part of its mission to incorporate information of such a fundamentally design‐oriented aspect, since this information was readily available elsewhere in greater detail. With the twelfth edition we are again incorporating the essential graphic information about the orders and how to compose and delineate them and have added information about the history, meaning, and uses of the orders in the past, present, and future.
In using and understanding the orders it is important to accept that they are not a static unchanging formula to be memorized and applied exactly by rote. Like a language, or any other means of sophisticated expression, it is not so much the specifics of the “words” that the orders represent, but rather that they provide a highly sophisticated grammatical language which can be used in many different modes of expression. Over time they have had a rich variety of sources and inspirations and have evolved in many different ways as well. First, they owe their initial existence and form through reference to actual buildings of the ancient world. Second, it is through codification and propagation throughout history that they have endured. Third, at key moments, individual architects have adapted and “swerved” from the accepted norms, and this has enabled the orders to grow and evolve in important ways.
The orders themselves, of which there were four identified in Roman times, were first described as such by Pollio Vitruvius, the architect and theoretician who wrote an architectural treatise in Augustan Roman times in 30–20 B.C. It was not until the Renaissance that interest in the accurate interpretation and use of the classical forms was revived in the treatises of Leon Battista Alberti (1450) and Sebastiano Serlio (1537). The work of both was a revival of Vitruvius, but also significantly went back to the actual Roman sources. The physical remains of Roman buildings were then being rapidly plundered and recycled in Renaissance buildings, so the appropriation of design elements was completely in keeping. It was Serlio who first codified five orders of classical architecture: Tuscan, Doric, Ionic, Corinthian, and Composite. Again in Summerson's words:
The orders present a sophisticated compositional system which is precisely governed by principles of proportion and harmony between parts. Each of the five orders has its own particular rules of proportion and characteristics controlling which parts and elements are used with each order. The key aspects of this are the proportion of each element (column diameter to height, base to column, column to entablature, for example) as well as how the repetitive elements are placed (intercolumniation). These principals are not arbitrary, but are based both on historical precedent and aesthetic principals of beauty and composition. Historically, the Doric order with its stout columns and narrow spaces between columns represented the prevailing conservatism of structural design, which by the time of the Ionic order, had evolved permitting more structurally daring use of more slender columns and longer spans.
The design principals of proportion and composition that underlie the orders are important in all aspects of design concerned with the appearance and perception of a structure. These principals remain important to us as designers even if we are not intent on creating a building which can be strictly defined as “classical.” Classicism has been employed on a widely varying spectrum of literalness as to the use of its form, and particularly during the first half of the twentieth century practitioners like Auguste Perret in France and Marcello Piacentini in Italy showed that a relatively stripped form of classicism could still express monumentality, permanence, and stability. Summerson argues that the mere presence of columns, capitals, moldings, and the other typical elements of classicism do not always represent classicism if specific forms are absent:
“There is, however, one point about this rather abstract conception of what is classical and it may be put as a question. Is it possible, you may ask, for a building to display absolutely none of the trappings associated with classical architecture and still, by virtue of proportion alone, to qualify as a ‘classical’ building? The answer must, I think, be ‘no’. You can say, in describing such a building, that its proportions are classical, but it is simply confusing and an abuse of terminology to say that it is classical. The porches of Chartres Cathedral are, in distribution and proportion, just about as classical as you can get, but nobody is ever going to call them anything but Gothic.
The fact is that the essentials of architecture—as expounded by the Renaissance—are to be found expressed, consciously or unconsciously, throughout the architectures of the world. And while we must incorporate these essentials in our idea of what is classical we must also accept the fact that classical architecture is only recognizable as such when it contains some allusion, however slight, however vestigial, to the antique ‘orders’. Such an allusion may be no more than some groove or projection which suggests the idea of a cornice or even a disposition of windows which suggests the ratio of pedestal to column, column to entablature. Some modern buildings—notably those of the late August Perret and his imitators—are classical in this way: that is to say, they are thought out in modern materials but in a classical spirit and sealed as classical only by the tiniest allusive gestures.”11
It is in two contexts and with two objectives that this revised presentation of the orders is offered: First, in the spirit of all other solutions and details provided in Architectural Graphic Standards, these orders are intended for use by those who practice classical architecture—a group always growing in number. Second, the ideas and sensibilities which the orders represent have a relevance that goes far beyond the practices of classical architecture and in fact applies to all practitioners who wish to touch upon human perception and empathic response to habitation.
Classical architecture is based on five distinct and formalized systems of columns and horizontal supports, called the orders. A proportional system in which the parts and divisions of each order, measured in multiples or divisions of the diameter of the lowest part of the relevant tapered column shaft, distinguishes each unique order.
Scientific notation is used to abbreviate large numerical values in order to simplify calculations.
A radian is a way of measuring angles in addition to degrees. Radians are the primary unit of angular measurement used in calculations.
The distance s, which a point p on the rim of a rotating wheel covers, is called linear distance. The angle θ, the intercepting angle, is measured in radians.
The linear speed v, of the point p around the rim of a rotating wheel, is the time taken t for a point to travel the distance s.
The angular speed w, of the point p around the rim of a rotating wheel is the time taken, t, for the point to travel the angular distance, θ. The angular distance can be measured in degrees, revolutions, or radians. The resulting units of angular speed depend on the units used for angular distance and time.
A light ray reflects from a surface such that the angle of reflection equals the angle of incidence.
When a light ray traveling through a transparent medium strikes another transparent medium, part of the ray is reflected and part is refracted, entering the second medium. The angle of the refracted ray depends on the angle of incidence and the index of refraction of both mediums.
When light attempts to move from a medium with a high index of refraction to a medium with a low index of refraction, there is a particular angle of incidence large enough that the angle of refraction reaches 90°. The transmitted light ray moves parallel to the surface of the first medium and no more light is transmitted.
This angle of incidence is called the critical angle and depends on the indexes of refraction of the two mediums. Any angle of incidence larger than the critical angle is reflected back into the first medium.
An object of initial length L0 at some temperature. With a change in temperature of ΔT, the length increases ΔL. The constant a α is called the average coefficient of linear expansion for the given material.
An object of initial area A0 at some temperature. With a change in temperature of ΔT, the area increases ΔA. The constant g γ is the average coefficient of area expansion for the given material.
A mass of initial volume V0 at some temperature. With a change in temperature ΔT, the volume increases ΔV. The constant β is called the average coefficient of volume expansion for a given material.
The architectural area of a building is the sum of the areas of the floors, measured horizontally in plan to the exterior faces of perimeter walls or to the centerline of walls separating buildings. Included are areas occupied by partitions, columns, stairwells, elevator shafts, duck shafts, elevator rooms, pipe spaces, mechanical penthouses, and similar spaces having headroom of 6 ft. and over. Areas of sloping surfaces, such as staircases, bleachers, and tiered terraces, should be measured horizontally in plan. Auditoriums, swimming pools, gymnasiums, foyers, and similar spaces extending through two or more floors should be measured once only, taking the largest area in plan at any level.
Mechanical penthouse rooms, pipe spaces, bulkheads, and similar spaces having a headroom less than 6 ft. and balconies projecting beyond exterior walls, covered terraces and walkways, porches, and similar spaces shall have the architectural area multiplied by 0.50 in calculating the building gross area.
Exterior staircases and fire escapes, exterior steps, patios, terraces, open courtyards and light wells, roof overhangs, cornices and chimneys, unfinished roof and attic areas, pipe trenches, and similar spaces are excluded from the architectural area calculations. Interstitial space in healthcare facilities is also excluded.
The architectural volume of a building is the sum of the products of the areas defined in the architectural area times the height from the underside of the lowest floor construction to the average height of the surface of the finished roof above, for the various parts of the building. Included in the architectural volume is the actual space enclosed within the outer surfaces of the exterior of outer walls and contained between the outside of the roof and the bottom of the lowest floor, taken in full: bays, oriels, dormers; penthouses, chimneys; walk tunnels; enclosed porches and balconies, including screened areas.
The following volumes are multiplied by 0.50 in calculating the architectural volume of a building; nonenclosed porches, if recessed into the building and without enclosing sash or screens; nonenclosed porches built as an extension to the building and without sash or screen; areaways and pipe tunnels; and patio areas that have building walls extended on two sides, roof over, and paved surfacing.
Excluded from the architectural volume are outside steps, terraces, courts, garden walls; light shafts, parapets, cornices, roof overhangs; footings, deep foundation, pilling caissons, special foundations, and similar features.
The net assignable area is that portion of the area that is available for assignment to an occupant, including every type of space usable by the occupant.
The net assignable area should be measured from the predominant inside finish of enclosing walls in the categories defined below. Areas occupied by exterior walls, partitions, internal structural, or party walls are to be excluded from the groups and are to be included under “construction area.”
In commercial buildings constructed for leasing, net areas are to be measured in accordance with the “Standard Method of Floor Measurement,” as set by the Building Owners and Managers Association (BOMA).
The net rentable area for offices is to be measured from the inside finish of permanent outer building walls, to the office or occupancy side of corridors and/or other permanent partitions, and to the center of partitions that separate the premises from adjoining rentable areas. No deductions are to be made for columns and projections necessitated by the building.
The net rentable area for stores is to be measured from the building line in case of street frontages and from the inside finish of other outer building walls, corridor, and permanent partitions and to the center of partitions that separate the premises from adjoining rentable areas. No deductions are to be made for vestibules inside the building line or for columns that are projections necessary to the building. No addition is to be made for projecting bay windows.
If a single occupant is to occupy the total floor in either the office or store categories, the net rentable area would include the accessory area for that floor of corridors, elevator lobbies, toilets, janitors' closets, electrical and telephone closets, air‐conditioning rooms and fan rooms, and similar spaces.
The net rentable area for apartments is to be measured from the inside face of exterior walls, and all enclosing walls of the unit.
Various government agencies have their own methods of calculating the net assignable area of buildings. They should be investigated if federal authority of funding applies to a project. Also, various building codes provide their own definitions of net and gross areas of buildings for use in quantifying requirements.
