N.Y. Multiple Dwelling Law § 171: Alterations

§ 171. Alterations. 1. A building, other than a frame building,

originally occupied as a one-family or two-family dwelling may be

altered to a converted dwelling if its bulk and volume has not been

increased since April eighteenth, nineteen hundred twenty-nine, and if

it is converted in conformity with the other provisions of this article.

2. Except as permitted in subdivision nine of section nine and

subdivision six of section one hundred seventy-two, it shall be

unlawful:

a. To increase the height or number of stories of any converted

dwelling or to increase the height or number of stories of any building

in converting it to a multiple dwelling.

b. To reduce the room or window area of any converted dwelling or make

any other alteration therein if such alteration decreases the light,

ventilation, fire protection or sanitation thereof.

c. To convert to a multiple dwelling any dwelling which exceeds six

stories in height unless it was occupied as a multiple dwelling on April

fifteenth, nineteen hundred thirty;

d. To convert any dwelling to a class A multiple dwelling occupied by

five families or more upon any story unless such dwelling is fireproof

or is converted in conformity with the requirements of subdivision three

or was occupied as a class A multiple dwelling on April fifteenth,

nineteen hundred thirty.

e. To combine any converted dwelling with another building which

exceeds six stories in height.

f. To enlarge or extend any converted dwelling so as to exceed by more

than twenty-five per centum the area which such dwelling had on any

floor at the time of its conversion, except as provided in paragraph h.

g. To convert to a multiple dwelling any dwelling not so converted

before April fifteenth, nineteen hundred thirty, if after such date it

has been increased in number of stories or combined with another

building more than six stories in height or enlarged or extended so as

to exceed by more than twenty-five per centum the area of such dwelling

or its area on any floor as shown by the plan approved by the department

before its erection, except as provided in paragraph h.

h. Paragraphs f and g shall not apply to, or be deemed to prohibit,

any rear extension of the first story of any converted dwelling

permitted under the provisions of section one hundred seventy-two.

3. Converted dwellings six stories or less in height may be combined

if such dwellings when combined conform to the requirements of this

subdivision.

a. No frame building shall be a part of any such combination.

b. Every entrance hall, stair hall, public hall, stair and stair

enclosures shall be constructed of fireproof materials throughout and

every door opening therefrom and door assembly shall be fireproof with

the door self-closing and without transoms. Every public hall shall be

at least three feet six inches in clear width and enclosed with masonry

walls not less than eight inches in thickness. Every stair and stair

hall shall be constructed and arranged throughout as provided in

sections thirty-five, thirty-six, fifty and fifty-two, and as provided

in sections one hundred two, one hundred five and one hundred six for

fireproof dwellings erected after April eighteenth, nineteen hundred

twenty-nine, and shall be at least three feet in clear width with all

landings at floor levels at least three feet six inches in clear width.

In every combination of three or more such dwellings, fire-stairs shall

be located so that there shall be horizontal access in the public hall

from every apartment to two or more fire-stairs, one or more of which

shall be within fifty feet horizontally in the line of travel of one or

more required means of egress from such apartment. Every stair,

fire-stair and fire-tower shall extend to the roof through a fireproof

bulkhead constructed in compliance with the provisions of section one

hundred four for fireproof multiple dwellings.

c. The ceiling of the cellar, or of the lowest story, if there be no

cellar, shall be fire-retarded.

d. There shall be at least two means of egress from every apartment or

suite of rooms containing three or more living rooms. Such means shall

be remote from each other, with the first means opening to a public hall

which is connected with a stair not more than fifty feet distant from

such means of egress. The second means of egress shall be directly

accessible to a fire-tower or fire-stair, or to an outside fire-escape.

e. No window to the outer air shall be required opening from any

public hall, vestibule, stair, or stair hall artificially lighted and

ventilated mechanically as provided in section one hundred seven for

fireproof multiple dwellings. If any windows are provided, they and

their assemblies shall be fireproof and glazed with wire glass, and if

such windows are used in lieu of mechanical ventilation and artificial

lighting, they shall also be arranged as provided for stairs and public

halls in non-fireproof multiple dwellings erected after April

eighteenth, nineteen hundred twenty-nine.

f. No elevator shall be required, but should one be installed it shall

conform to the provisions of section fifty-one relating to elevators and

section one hundred five for fireproof dwellings.

g. None of the combined dwellings shall be required to comply with

sections one hundred seventy-eight, one hundred eighty-five, one hundred

eighty-seven, one hundred eighty-eight and one hundred ninety or with

subdivisions one, two and three of section one hundred eighty-nine.

h. When any business is conducted in any portion of dwellings so

combined, the ceilings and walls of such portion shall be fire-retarded

and every door and door assembly shall be fireproof with the door

self-closing.

4. Nothing in this article shall be deemed to prohibit a combination

of class A and B occupancy in any converted dwelling. If more than fifty

per centum of the rooms therein are used for class A occupancy, the

dwelling shall be deemed a class A dwelling, otherwise a class B

dwelling.