Columbia University Libraries Digital Collections: The Real Estate Record

Real estate record and builders' guide: [v. 99, no. 2567: Articles]: May 26, 1917

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REAL ESTATE AND (Copyright. 1917, by The Record and Quid* Co.) NEW YORK, MAY 26, 1917 FLEXIBILITY OF BUILDING HEIGHT LIMITS Varying Conditions in Older and Newer Sections of City Presented Many Problems in Drafting Zone Law MUCH has been said and written of late about the restrictions im¬ posed by the Zone Law upon the height of buildings, but little has been heard about the flexibility and adaptability of this latest addition to the Building Law of New York City. The resolution adopted by the Board of Estimate on July 25, 1916. regulates the uses or occupancies of buildings and other premises, the heights of buildings and the sizes of open spaces. The sec¬ tion which will have the greatest effect upon the physical appearance of the city, the section which will create a new archi¬ tecture for the street facades of build¬ ings, is that regulating building heights. Its chief excellence and greatest promise for the future lie in its flexi¬ bility. It is not a flat limitation of so many feet, above which no structure may go, as is had in Boston and Wash¬ ington, nor is it a fixed height of cornice line to which all . buildings must con¬ form, as is prevalent in some European cities. Both of these tend to limit a city's architecture unnaturally, and to stamp it with the mark of artificial reg¬ ulation. Unlike these, New York's height limitation is based upon a com¬ mon sense principle so administered, as to conform to aporoved standards of development in each section of the city, and to preserve to every lot a certain minimum of the common stock of light and air. The problem so to draft a law that a new city should afford to each building its proportionate share of the great es¬ sentials, light and air, would be difficult enough, but to adjust such a law to the widelv varying conditions of a city, part of which is comparatively old and part of which has never been improved, would seem to involve almost insurmountable difficulties. Especially in lower Man¬ hattan is the height to which a building may be erected of essential interest to the land owner. Real estate values have been long established on the basis of height possibilities limited only bv the construction engineer. Height limits based unon considerations of adeauate natural lishtine and ventilation will be wisely adjusted to conserve present land valuations and to permit a development —more scientific, and more equitable, be it granted—but at least on approximate¬ ly the same scale as in the past. The financial section of the city has therefore been given the greatest lati¬ tude. Other sections have had more stringent hei.ght regulations drafted for them, but in everv case, from the ware- bouse and retail business sections to the detached private house neighborhoods, the present development has molded the rules for the future. The new hei.ght limits are designed to conform with the type of buildine improvement now ex¬ isting or contemnlated. Underlying the whole plan of height limitation is one chief consideration namely, that hVht and air are necessary to the public welfare, that they are to be enjoyed by the greatest number, only if every propertv owner is made to respect his nei.ghbors' rights, and that the prop¬ erty owner, who is prevented from ex¬ travagant heights, is enabled to demand a greater rent because his rooms receive By FRANCIS P. SCHIAVONE greater light. His neighbor is similarly benefited. .A.nd because this end could be attained without imposing a flat limi¬ tation on a maximum, none was adopted. Instead, the street width was made the basis for the height limits upon the street line. Thus a wall upon the street line of a wide street may be built higher than upon a narrow street. This is done so that anv height may he had. so long as a predetermined "light angle" or "sky angle" is maintained. This general prin¬ ciple is applied throughout the city, but the ratio of height to street width varies in diflferent localities. Thus in the finan¬ cial district of lower,Manhattan it is two and one-half times the street width, in the warehouse sections along parts of the Manhattan, Brooklyn and Bronx waterfronts and the lower part of Man¬ hattan, two times; in the more intensely developed tenement sections, one and one-half times, and in the remainder of the citv. one and one-quarter or one times the street width. The flexibility of these nrovisions is shown by the fact that in the most restricted sections, a wall upon the street line may be erected to a hei.ght of 100 feet, while a wall upon a 50-foot street in the least restricted district could go up only 125 feet. On the other hand, the most restricted dis¬ trict mi.ght have a wall on the line of a SO-foot street, onlv 50 feet high, while upon a 100-foot street, in the least re¬ stricted district, it mi^ht go up 250 feet. Severity of Rule Tempered. The severity of this rule upon lots fronting upon very narrow streets has been tempered by the provision that all streets less than 50 feet wide shall be considered as though they were 50 feet wide. Similarly, to prevent abuse of the other extreme, streets more than 100 feet wide, are considered to be 100 feet. All streets between 50 and 100 feet are taken at their actual width. This system of height limits of street- line walls, based uoon street widths, will work out admirably in a new street where there are no existing buildings to introduce new questions of justice or enuity. But where a street is partially built upon by structures higher than the new limits, a new method of adjustment must be found to indemnify the neigh¬ bors of the excessively high building for the loss of light and air attributable to il. and to eive them an opportunity equal to that which was enjoyed by the owner of the tall building. To accomplish this local adjustment of the new to the old, and to combine in it full consideration of the efifect of the existing tall biiildinp' upon adjacent lots, with a provision to prevent undue in¬ jury to other nearbv nroperty. an in¬ crease of the height limit by the avera.ge excess hei.e'ht was considered most ap¬ propriate. The resolution states: (e) When at the time plans are filed for the erection of a building there are build¬ ings in excess of the height limits herein provided within 50 feet of either end of the street frontage of the proposed building or directly opposite such building across the street, the height to which the street wall of the proposed building may rise shall be increased by an amount not greater than the average excess height of th© walls on the street line within RO teet of either end of the street frontage of the proposed build¬ ing and at right angles to the street front¬ age of the proposed building on tha opposite side of the street. The average amount of such excess height shall be computed by ad¬ ding together the excess heights above the prescribed height limit for the street front¬ age in question of ail of the walls on the street line of the buildings and parts of buildings within the above defined front¬ age and dividing the sum by the total num¬ ber of buildings and vacant plots within such frontage. The height limits heretofore discussed are those placed upon walls erected on the street line, but to permit buildings to be erected to as great heights as the appropriate development of the land or the ideas of the owner may dictate, the set-back rule has been incorporated in the height restriction plan. This per¬ mits an-v building to go up any height, provided it sets back from the street line a certain number of inches for each foot of its height above the hei.ght limit speci¬ fied for the street wall. The set-back rule may be said to remove the height limits and to substitute therefor a sys¬ tem of hei.ght penalties under which the conflict between cost of construction and the value of floor space will determine the height of the building. This system adds another factor of flexibilitv to the height limits based on street widths and may be considered as allowing any hei.ght providing every part of the structure be kept below a plane extendine from the center of the street ("of a width between SO and 100 feet), through the heio-ht limit on the street line. Thus in a two and one-half times district, a buildine mav go up on the street line of a 100 foot street, 250 feet, and above that height may go up in¬ definitely five feet for every one foot that the buildine or that part of it above the street line limit sets back from the street line. In the two times district, the set-back ratio is 1 to 4, in the one and one-half times district 1 to 3. in the one and one-quarter times district 1 to 2'^. in the one times district 1 to 2. This set-back principle is to be ob¬ served not only in that form of set-back which consists of a flat roof and a verti¬ cal wall, but also in the mansard form or any combination of the two. It can readilv be seen that there is no danger of a uniformitv of cornice line or building heights. On the contrary, the prosoect is a most alluring one for the architect of genius. The rnolding of mass on mass in set-back pavilions and the pleasing- treatment of graceful man¬ sards aflford a wide latitude in the design of exteriors. The imasination alone can picture a citv of buildings erected under such rules—a citv. every street of which will have an increased share of sun and skv li.eht. and almost every building of which will present some new aspect or novel feature of structural beauty. At every intersection of streets of different widths, there would ordinarily be a conflict of the height limits, that on the narrow street being more severe than on the wide. To obviate this con¬ flict the greater height limit of the wider street has been decreed to influence the frontage on the narrower street for a distance of 150 feet from the_ wider street for a single corner building, or otherwise for 100 feet. The special lati¬ tude given corner buildings is designed to permit full improvement of the?^ more valuable plots. Th« present