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