ZONING. The zoning of cities has had considerable influence on their architecture and on the preservation of their amenity. As practised in modern times it is a new movement and is still in the experimental stage.
Zoning in has come to be called zoning in English-speaking countries had its first inspiration and derived its name from the building regulations applied in Central Europe before 1909. Since 1875 German and Swedish cities have applied zoning regulations to the zones around their built areas, with a view to controlling the heights and densities of buildings in town extensions. The effect of the German laws, and of the fairly rigid control exercised under them, has been to procure a greater spaciousness and uniformity of development than would have oc curred under ordinary building regulations.
When the Town Planning Act was passed in England in 1909, it had for its general object the control of the development of land likely to be used for building purposes. In so far as it provided for regulation of heights, densities and uses of buildings it related primarily and almost solely to entirely new building development. The fact that it is so limited has prevented it from being an effec tive instrument in procuring architectural control. But part of its object is to provide such control over new developments. Section 59 (2) in the original Act of 1909 was as follows: "Property shall not be deemed to be injuriously affected by reason of the making of any provisions inserted in a town planning scheme, which, with a view to securing the amenity of the area included in the scheme or any part thereof, prescribe the space about buildings or limit the number of buildings to be erected, or prescribe the height or character of buildings, and which the Ministry of Health, having regard to the nature and situation of the land affected by the provisions, consider reasonable for the purpose." It is noteworthy that the purpose for which the restrictions in an English scheme are imposed is to secure the "amenity of the area." For the reason given, the law has not influenced the re development of built-upon areas. Being primarily intended to regulate residential buildings it has had little effect also on the architecture of other buildings. It has introduced into England a spacious type of development for the cottages of the working classes. On the whole, it has improved cottage architecture and introduced a better arrangement and grouping of buildings.
In town planning schemes public authorities may take power to approve or disapprove the elevation of, and the materials to be used in, buildings. For the purpose of exercising this power the
authority must constitute a special advisory committee of those members of which one shall be an architect nominated by the Royal Institute of British Architects.
Zoning in the United to what has hap pened in England zoning in the United States has been too limited in its application to undeveloped areas and has been chiefly applied to areas already built upon.
In New York zoning has exercised a greater influence on archi tecture than in any other city. New York was the first city in the western continent to impose zoning regulations. Its Zoning Resolution was passed in 1916 and had for its object the restric tion of the height and bulk of buildings and the regulation of their uses. It did not directly attack the problem of density, except by restricting height and bulk.
New York was zoned just when the steel frame and the elevator had begun to have a profound influence on building and archi tecture (q.v.). During the 12 years since the passing of the Act (1916-28) enormous changes have taken place in the city, and an extensive rebuilding programme has been carried out.
The zoning law in New York is intended to relieve street con gestion, for, other things being equal, it is obvious that such congestion is directly proportionate to the bulk of the buildings flanking the street. The Paris law limits the straight vertical height to 20 metres; above that, additional storeys must remain within the arc of a circle of fixed radius. The London regulations permit of 8o ft. vertical height and two supplementary storeys which must remain behind a sloping line of 75 deg. from the horizontal. In New York the vertical height is now determined by the width of the street, but varies according to the "zone" or district in which the given property is situated. These districts are classified as follows : "One-time" districts, "one-and-one-half time" districts, "two-time" districts and "two-and-one-half-time" districts. That is to say, the straight vertical height may be equal to the width of the street in residence zones ; it may be one-and one-half times the width of the street in certain residence and business zones; twice the width in the principal business centres and two-and-one-half times in the Wall Street financial section. For the purpose of the law, no street is considered less than so ft. or more than ioo ft. wide. Additional storeys above the vertical height must remain back of a line drawn from the centre of the street through a point on the top front of the vertical height.