COMMERCIAL BUILDINGS Under this heading are included all buildings designed for the purchase, sale, exchange or transport of goods or for the work involved in the financing of businesses, etc. In former times the bulk of business was carried on between individuals and their more or less immediate neighbours ; when the business concerns, then comparatively small, built at all it was for themselves ; 4o years ago a small building or one or two floors in a larger one sufficed. The corporation, the trust and the super-trust have since been organized. To-day nearly all business is national in scope, and much of it international; it requires great headquarters in the principal cities, notably the larger ones, and sky-scrapers in concentrated masses, grouped for centralized business as in New York, co-ordinate and speed it up. Business has either to build for itself on a vast scale or else to rent space in the build ings now being erected with a rapidity heretofore unequalled (see ARCHITECTURE) . Building space is produced where it is needed and where speculating builders think it will be; it is manufac tured, rented, sold ; it differs from other merchantable commodities only in that it cannot be transported ; but for this reason, and be cause considerable capital is necessary for any building and full returns on the investment may not come in for years, speculation in this field is small.
The need for larger buildings and the introduction of skeleton construction, two factors that appeared almost simultaneously, have resulted in the new American architecture whose buildings have tremendous bases and multi-storeyed towers (see ARCHITEC TURE) . To preserve adequate light and air for all, however, in most American cities the form of the new buildings is restricted by law, with a tower of unlimited height sometimes permitted on an area equal to one-fourth of the lot (see ZONING). Aestheti cally, the most refined effect and greatest symmetry, and practi cally, the best lighting and ventilation, are obtainable when this tower rises from the centre of the lot, a position in which it can also be taller and structurally stronger than when placed elsewhere.
Since the office building of the sky-scraper type is the most distinctive example of commercial architecture, let us consider it in detail. The usual procedure in most plan studies is to start with the ground floor and build up. But in planning office build ings, and this applies to apartments and hotels as well (see SOCIAL ARCHITECTURE), the architect reverses this process and plans from the top down. That is to say, he develops a typical upper-floor plan first, because the major income is derived from these typical floors, and if some sacrifice is to be made, it can better be made on the ground floor than on the office floors. A typical office unit is first determined upon, a series of such units is arranged along both sides of a corridor, and then the line of vertical circulation (lifts or elevators) is fixed at a central point on this corridor so that no tenant is obliged to walk more than 1 oo ft. from his office door to an elevator. Utility spaces—toilets, cleaners' closets, vent shafts, flues, etc.—are then added and the plan is completed. A type of plan which, with the ever-increasing concentration of business and the development of larger and larger organizations, is rapidly becoming popular, is that in which a building is de signed as a solid mass, as opposed to the more usual type in which it contains area-ways and courts. The typical upper-floor plan of such buildings shows a series of connecting offices on the outside, while the artificially lighted and ventilated core of the building is given over to elevators and rooms for storage, conferences, etc., belonging in common to the occupants of the various offices. This type necessitates each floor being occupied by a complete organiza tion, or at least members of the same profession, and in New York, for example, the installation of common services, notably for doctors, in whole buildings occupied by them, has been carried even further to include rooms for special examinations, appliances and even attendants.
Authorities differ as to what constitutes the ideal office unit ; they agree that it is better to have less space (less capital invest ment) permanently rented at a high figure than much space par tially rented at a low figure. Lighting is the important factor here. The depth, i.e., distance from windows to corridor, of a well lighted office is never more than twice the clear ceiling height. Twenty feet is better than twenty-five. The width of the unit varies with the distance between steel columns, which economical engineering consideration places at not less than 15 ft. nor more than 2 2 feet. In the best office units each internal division can be subdivided into smaller rooms in the single large office unit. Although a 4 ft. corridor might serve all practical purposes, the width should increase with the length for the sake of beauty of proportion. Corridors should also increase in size as they approach the elevators.
The building lot at the architect's disposal determines the arrangement of offices. It should be noted that "dark" spots, such as always occur where a wing joins the main building, are used, as far as possible, for the necessary utilities, such as elevators, stairways and smoke towers. Toilets can be artificially ventilated and lighted, but it seems better to place them on small back courts, which furnish inferior office space at best, thereby retaining some degree of natural light and full natural ventilation. The British building laws require outside toilets, always; i.e., they must always have outside windows, no matter how much artificial ventilation may be provided.
Elevators are often the key to the plan scheme and are usually grouped together for greater service efficiency. Even small build ings have at least two (because of possible breakdown), and if more are needed on account of greater floor area or greater num ber of storeys, they are so placed that a tenant waiting for a lift may be able to step easily to the first one that flashes a signal. A battery of six elevators, three facing three, is the ideal arrange ment. Eight, four facing four, are possible. More than eight in one battery is not practical, because then the passenger might not reach the lift before it had passed. If more than one system is installed, the systems must be separated enough for each to serve effectively an entirely new area, and the plan problem simply re peats itself ; i.e., two buildings side by side, but with connecting corridors.
Just as 1 oo ft. each way from the elevator line is the conven ient limit one may go horizontally, i 5 storeys is about the limit of effective service for a single battery. As the building with ground area for one group of elevators increases in height, it may require a battery of more than eight, in which case the problem becomes two buildings, one placed on top of the other, with the vertical circulation of the upper structure running through the lower as an "express" service.
The number of floors below the street level depends on the height and, to some extent, on the location of the building. Some very high buildings have as many as five floors below the street level. In some, situated near subway stations, tunnels run from the building to the station; the first basement floor then becomes a second entrance hall ; however, it is usually simply treated and such services as boot-black stands and extra telephones are in stalled. Caretakers' quarters, boilers and other mechanical equip ment are located on various of these subterranean floors according to the needs of the problem.
When a building occupies an entire city square, it requires four distinct lines of distributing elevators instead of one or two. It becomes four buildings instead of one; i.e., four similar units with connecting corridors. It might be possible to provide means of transporting people through buildings in some way other than or additional to the present system of elevators. None has yet been tried. There has been no building large enough. A large city square, 200 ft. by Boo ft., generally faces two avenues of which one is more important. While in a building occupying such a square several entrances would be placed along the side streets and both avenues, a starting point for distribution might be determined at a point near the most important avenue. A moving stair or similar contrivance might be developed to carry passengers toward the rear and sides of the building while rising. This would probably serve only the first io or 12 storeys, as, owing to the narrow side streets, most building laws permit an average of only about 12 storeys, with a tower on an area equal to one-fourth of the base. Due to the size of the average city squares, buildings more than 200 ft. wide from the elevator centre are improbable.
The architectural treatment of a building for advertising pur poses is receiving increasing consideration. The Telephone Com pany and Sears Roebuck and Company are but two examples in the United States that, each having their own architects, give their buildings throughout the country a distinctive appear ance. In the American Radiator building, New York city, Ray mond Hood has portrayed in the black shaft and the gold and red crest the glow and warmth of heating apparatus. Such advertis ing features, used as an inherent part of a building's composition, have aesthetic as well as commercial value. The time is coming when crude signs will be considered as offensive as foul smells; restrictions on noise, smells and ugliness will increase as the aesthetic sense of the public is educated.
The illumination of the exteriors of buildings at night will, probably, play an important part in the city architecture of the future. Already flood-lights are used on the upper set-backs to illuminate the topmost storeys. With the development of new materials and the ever-improving methods of lighting, it is possible that the giant buildings of future cities will be beacons that light both directly and by reflection the streets themselves.