Chapter 4 - Special Regulations Applying in Flood Zones
GENERAL PURPOSES
The provisions of this Chapter establish special regulations which are designed to encourage flood-resilient building practices for new and existing buildings and in so doing to promote and protect public health, safety and general welfare. These general goals include, among others, the following purposes:
(a) to facilitate the development and alteration of buildings in flood zones consistent with the flood-resistant construction standards of Appendix G of the New York City Building Code;
(b) to enable buildings to be constructed or retrofitted pursuant to flood-resistant construction standards with a comparable amount of usable interior space to what is generally permitted within the applicable zoning district;
(c) to allow sea level rise to be incorporated into the design of buildings in flood zones in order to provide longer-term and greater protection from flood risk than what is currently required by Appendix G of the New York City Building Code;
(d) to mitigate the effects of elevated and flood-proofed buildings on the streetscape and pedestrian activity; and
(e) to promote the most desirable use of land in accordance with a well-considered plan and thus conserve the value of land and buildings, and thereby protect the City’s tax revenues.
GENERAL PROVISIONS
Definitions
Definitions specifically applicable to this Chapter are set forth in this Section and may modify definitions set forth in Section 12-10 (DEFINITIONS). Where matter in italics is defined both in Section 12-10 and in this Chapter, the definitions in this Chapter shall govern.
Cottage envelope building
A “cottage envelope building” is a single- or two-family detached residence located within R1 through R5 Districts, developed, enlarged, or altered, pursuant to any of the optional provisions of Section 64-33 (Special Regulations for Cottage Envelope Buildings), provided that:
- such single- or two-family detached residence complies with Section 64-333 (Height and setback regulations for cottage envelope buildings); and
- is located within a zoning lot that has a lot area that is less than that required by the applicable district; and
- has a lot width that is either:
- less than that required under the provisions of Section 23-32 (Minimum Lot Area or Lot Width for Residences) in R1, R2, R3-1, R3-2, R3X, R4, R4A, R5, and R5A Districts; or
- equal to or less than 30 feet in R3A, R4-1, R4B, R5B, and R5D Districts; or
- has a depth of less than 95 feet at any point.
- has a lot width that is either:
All cottage envelope buildings shall also be flood-resistant buildings.
First story above the flood elevation
The “first story above the flood elevation” shall be the finished floor level of the first story located at or above the level at which a building complies with flood-resistant construction standards and, for buildings utilizing the reference plane, shall be no lower than the particular level established as the reference plane.
Flood map
“Flood map” shall be the most recent map or map data used as the basis for flood-resistant construction standards.
Flood-resistant building
A “flood-resistant building” is a building or other structure, which complies with all applicable flood-resistant construction standards.
Flood-resistant construction elevation
The “flood-resistant construction elevation” shall be the level of flood elevation required by Appendix G of the New York City Building Code for the “Flood design classification” of a building or other structure as set forth therein, or a height of two feet above the lowest grade adjacent to the building or other structure, whichever is higher.
Flood-resistant construction standards
“Flood-resistant construction standards” are the construction standards set forth in Appendix G of the New York City Building Code for “Post-FIRM Construction” that aid in protecting buildings or other structures in flood zones from flood damage, and governs both building or other structures that are required to comply with such standards and those that voluntarily comply. For buildings or other structures utilizing the provisions of this Chapter, flood-resistant construction standards shall be applied up to the flood-resistant construction elevation or higher.
High-risk flood zone
The “high-risk flood zone” is the area, as indicated on the flood maps, that has a one percent chance of flooding in a given year.
Lowest usable floor
The “lowest usable floor” of a building is the lowest floor of such building that contains floor area, and may include basements and cellars, as defined in Section 12-10 (DEFINITIONS).
Moderate-risk flood zone
The “moderate-risk flood zone” is the area, as indicated on the flood maps, and not within of the high-risk flood zone, that has a 0.2 percent chance of flooding in a given year.
Primary frontage
For the purposes of applying the provisions of Section 64-322(c), a “primary frontage” shall include:
- in Commercial Districts, frontages that meet the criteria for a “primary frontage” as defined in Section 37-311;
- in M1 Districts paired with Residence Districts, frontages along:
- wide streets;
- narrow streets within 50 feet of a wide street; and
- narrrow streets where an M1 District paired with a Residence District is mapped along an entire block frontage; and
- frontages where non-residential uses are required at the ground-floor level pursuant to a Special Purpose District or waterfront public access area.
Reference plane
The “reference plane” is a horizontal plane from which the height and setback regulations governing a building or other structure may be measured, in accordance with certain provisions of this Chapter. The reference plane shall not be located above the first story above flood elevation, as applicable.
For zoning lots located wholly or partially within the high-risk flood zone, the reference plane may be established at any level between the flood-resistant construction elevation and a height of 10 feet above the base plane or curb level, as applicable. However, where the flood-resistant construction elevation exceeds a height of 10 feet above the base plane or curb level, as applicable, the reference plane may be established at the flood-resistant construction elevation.
For zoning lots located wholly or partially within the moderate-risk flood zone, the reference plane may be established at any level between the flood-resistant construction elevation and a height of five feet above the base plane or curb level, as applicable.
Applicability
The optional provisions of this Chapter shall apply to zoning lots located wholly or partially within flood zones, as follows:
- For all zoning lots in the flood zone
The provisions of Sections 64-31 (Special Bulk Regulations for All Buildings) and 64-41 (Special Parking Regulations for All Buildings), inclusive, may be applied to all zoning lots, regardless of whether buildings or other structures on such zoning lots comply with flood-resistant construction standards. - For zoning lots containing flood-resistant buildings
The provisions of Sections 64-20 (SPECIAL USE REGULATIONS), 64-32 (Special Bulk Regulations for Flood-resistant Buildings), 64-42 (Special Parking Regulations for Flood-resistant Buildings), and 64-60 (SPECIAL REGULATIONS FOR NON-CONFORMING USES AND NON-COMPLYING BUILDINGS), inclusive, may be applied only to zoning lots containing flood-resistant buildings, including cottage envelope buildings, as applicable, and Section 64-33 (Special Bulk Regulations for Cottage Envelope Buildings) may additionally be applied exclusively to zoning lots containing cottage envelope buildings. Where such provisions are utilized, the provisions of Section 64-50 (STREETSCAPE REGULATIONS), inclusive, shall apply. - For portions of buildings
The following provisions may be applied to portions of buildings as follows:- the provisions of Section 64-311 (Special floor area modifications for all buildings) and 64-313 (Special height and setback regulations for all buildings) may be applied to portions of buildings, regardless of whether such portions comply with flood-resistant construction standards;
- the provisions of Section 64-32 (Special Bulk Regulations for Flood-resistant Buildings), inclusive, may be applied to portions of buildings, provided that such portions comply with flood-resistant construction standards for the entirety of its vertically contiguous segments. Where such provisions are utilized within portions of buildings, the provisions of Section 64-50 (STREETSCAPE REGULATIONS), inclusive, shall apply.
The regulations of all other chapters of this Resolution are applicable, except as superseded, supplemented or modified by the provisions of this Chapter. In the event of a conflict between the provisions of this Chapter and other regulations of this Resolution, the provisions of this Chapter shall control.
SPECIAL USE REGULATIONS
The provisions of this Section, inclusive, are optional, and are only applicable to zoning lots located wholly or partially within flood zones. The provisions of this Section, inclusive, may be applied to zoning lots regardless of whether buildings or other structures on such zoning lots comply with flood-resistant construction standards. For such zoning lots, the underlying use regulations shall apply, except where permitted to be modified by this Section, inclusive.
C1 C2
In the districts indicated, the provisions of Section 32-421 (Limitation on floors occupied by commercial uses) may be modified for buildings containing residences such that the limitations set forth in paragraphs (a) or (b) of such Section need not apply.
The provisions of this Section, inclusive, are optional, and are only applicable to zoning lots located wholly or partially within flood zones. The provisions of this Section, inclusive, may be applied to zoning lots containing flood-resistant buildings, including cottage envelope buildings. For such zoning lots, the underlying use regulations shall apply, except where permitted to be modified by this Section, inclusive.
Measurement of height
In all districts, as an alternative to measuring heights from base plane, curb level, or other applicable datum, all height measurements in flood zones, including the number of stories permitted, as applicable, may be measured from the reference plane. However, this provision shall not apply to signs not affixed to buildings or other structures.
Ground floor use
In all districts, any applicable ground floor level requirements of this Resolution including, but not limited to, the location of such ground floor in relation to the adjoining sidewalk level, the height of a qualifying ground floor, restrictions of types of use, the minimum depth for certain uses, maximum width for certain uses, minimum transparency requirement, and parking wrap and screening requirements, may be modified as follows:
(a) In locations of the flood zone where flood-resistant construction standards prohibit dry-flood-proofing, thereby limiting uses other than parking, storage and building access from being located below the flood-resistant construction elevation, such ground floor level requirements need not apply.
(b) In all other locations of the flood zone, all regulations of this Resolution restricting the location of a ground floor in relation to the adjoining sidewalk level need not apply, provided that all other ground floor level regulations shall be applied to the lowest story above grade that is not solely used for parking, storage or building access, and further provided that the finished floor level of such story shall be located either at or below the level of the flood-resistant construction elevation or five feet above curb level, whichever is higher. All associated transparency requirements may be measured from such level of the finished floor instead of the level of the adjoining sidewalk.
SPECIAL BULK REGULATIONS
The provisions of this Section, inclusive, are optional, and are only applicable to zoning lots located wholly or partially within flood zones.
The provisions of Section 64-31 (Special Bulk Regulations for All Buildings), inclusive, may be applied to zoning lots regardless of whether buildings or other structures on such zoning lots comply with flood-resistant construction standards.
The provisions of Section 64-32 (Special Bulk Regulations for Flood-resistant Buildings), inclusive, may be applied to zoning lots containing flood-resistant buildings, including cottage envelope buildings.
The provisions of Section 64-33 (Special Bulk Regulations for Cottage Envelope Buildings), inclusive, may be applied to zoning lots with cottage envelope buildings.
The provisions of this Section, inclusive, are optional, and are only applicable to zoning lots located wholly or partially within flood zones. The provisions of this Section, inclusive, may be applied to zoning lots regardless of whether buildings or other structures on such zoning lots comply with flood-resistant construction standards. For such zoning lots, the underlying bulk regulations shall apply, except where permitted to be modified by this Section, inclusive.
For all buildings, the definition of floor area in Section 12-10 (DEFINITIONS) shall be modified in accordance with the provisions of this Section.
- Flood control devices
In all districts, for every linear foot of protection by temporary flood control devices and associated fixtures, including emergency egress systems that are assembled prior to a storm and removed thereafter, up to 15 square feet of floor space used for the storage of such devices may be excluded from the definition of floor area, provided that in no event shall such exempted floor space exceed 1,000 square feet. - Buildings containing non-residential uses
In Commercial and Manufacturing Districts, where the permitted commercial or manufacturing floor area ratio does not exceed 1.0, up to 500 square feet of floor space may be excluded from the definition of floor area, provided that:- the building is used exclusively for non-residential uses; and
- such floor space is located at or above the flood-resistant construction elevation.
The regulations for permitted obstructions in yards, courts and open space shall be modified in accordance with the provisions of this Section.
- Mechanical equipment
In all districts, where such energy infrastructure equipment or accessory mechanical equipment is elevated above the flood-resistant construction elevation, the underlying permitted obstruction regulations for such equipment may be modified as follows:- where any equipment is required to be located at least five feet from any lot line, such distance may be reduced to three feet for zoning lots that have less than the prescribed minimum lot area or lot width required by the applicable district regulations;
- the maximum height of such permitted obstructions for the applicable district:
- may be measured from the reference plane instead of the level of the adjoining grade or curb level, as applicable; or
- for zoning lots containing residences and a lot area greater than or equal to one and one-half acres, may exceed the applicable height limitations, provided that:
- such equipment is contained within a building or other structure that is located at least 30 feet from any legally required window;
- any stack associated with heating, ventilation, and air conditioning (HVAC) systems exhausts at a height at least as tall as the tallest building containing residences on the zoning lot; and
- such building or other structure complies with one point of the streetscape mitigations set forth in Section 64-52 (Ground floor level mitigation options); and
- the maximum area that such equipment may occupy within a required side yard, rear yard or rear yard equivalent, or any court containing legally required windows need not apply where the height of such obstructions do not exceed the applicable underlying height allowances, as modified by the provisions of paragraph (a)(2)(ii)(a) of this Section.
- Berms
In all districts, structural landscaped berms and associated flood gates, including emergency egress systems that are assembled prior to a storm and removed thereafter, shall be permitted obstructions in any required open space, yard or rear yard equivalent on the zoning lot, provided that the height of such berm does not exceed the highest flood-resistant construction elevation required on the zoning lot, or five feet above the lowest adjoining grade, whichever is higher. - Flood control devices
In all districts, temporary flood control devices and associated permanent fixtures, including emergency egress systems that are assembled prior to a storm and removed thereafter shall be permitted obstructions in yards and rear yard equivalents, courts, open space, public plazas, arcades, pedestrian circulation spaces and all other publicly accessible open spaces. However, permanent fixtures for self-standing flood control devices installed in publicly accessible open areas, arcades, and pedestrian circulation spaces shall be flush-to-grade. - Steps
In all Residence Districts, the provisions of paragraph (a)(8) of Section 23-442 (Additional permitted obstructions) shall be modified to allow steps within a required yard or rear yard equivalent, provided that such steps access any story located at or below the first story above the flood elevation.
The regulations for permitted obstructions to applicable height and setback regulations shall be modified in accordance with the provisions of this Section.
For Quality Housing buildings, or portions thereof, as an alternative to the provisions of paragraph (c) of Section 23-623, dormers may be a permitted obstruction within a required front setback distance above a maximum base height, provided that the aggregate width of all dormers at the maximum base height does not exceed 40 percent of the width of the street wall of the highest story entirely below the maximum base height. Such dormers need not decrease in width as the height above the maximum base height increases.
The provisions of this Section, inclusive, are optional, and are only applicable to zoning lots located wholly or partially within flood zones. The provisions of this Section, inclusive, may apply to zoning lots containing flood-resistant buildings, including cottage envelope buildings. For such zoning lots, the underlying bulk regulations shall apply, except where permitted to be modified by this Section, inclusive.
In all districts, as an alternative to measuring heights from base plane, curb level, or other applicable datum, all height measurements in flood zones, including the number of stories permitted, as applicable, may be measured from the reference plane, except as follows:
(a) for Quality Housing Buildings, any minimum base height requirements shall continue to be measured from the base plane; and
(b) the provisions of this Section shall not apply:
(1) to fences or other structures that are not buildings; and
(2) to buildings that are accessory to single- or two-family residences, except when mechanical equipment is located within such building.
Illustrative Examples
The following examples, although not part of the Zoning Resolution, are included to demonstrate the application of the optional height regulations available to zoning lots in flood zones. Specially, the examples illustrate how the defined terms reference plane, from which height is measured, relates to the flood-resistant construction elevation and the first story above the flood elevation. All terms are defined in Section 64-11 (Definitions).
EXAMPLE 1
A zoning lot located within the high-risk flood zone has a flood-resistant construction elevation (as defined in Section 64-11) that equates to being located six feet above grade (for illustrative purposes). The owner of a single-family detached residence would like to elevate the first habitable floor three feet above the flood-resistant construction elevation and wet-floodproof the ground floor up to that same level (nine feet above grade) to account for sea level rise projections.
Pursuant to Section 64-321, height measurements in flood zones, including height and setback regulations, may start from the reference plane, allowing the owner the necessary flexibility to address long-term climate change. For zoning lots located within the high-risk flood zone, the reference plane, may be established at any level between the flood-resistant construction elevation and a height of 10 feet above the base plane or curb level, as applicable. (Where the flood-resistant construction elevation exceeds 10 feet, the reference plane may still be established at the flood-resistant construction elevation, but that is not the case here.) While there is a level of flexibility built into the reference plane definition, the reference plane itself must also be located at or below the first story above flood elevation.
Considering the owner of such single-family detached residence is proposing to wet-floodproof the ground floor up to nine feet above grade, the first story above flood elevation becomes the finished floor level of the first story located at or above nine feet, which is, in this case, the second story. Therefore, the reference plane was able to be situated at that same level (nine feet above grade), but not higher.
EXAMPLE 2
A zoning lot located within the moderate-risk flood zone has a flood-resistant construction elevation (as defined in Section 64-11) of two feet above the lowest grade adjacent to the building or other structure. The owner of a mixed building that was flooded during Hurricane Sandy, would like to proactively comply with flood-resistant construction standards to be better prepared in the event of a future storm. To realize that, the owner decided to elevate the ground floor with a commercial use to the flood-resistant construction elevation, and dry-floodproof one foot above that for extra safety.
Pursuant to Section 64-321, height measurements in flood zones, including height and setback regulations, may start from the reference plane, allowing the owner the necessary flexibility to address long-term climate change. For zoning lots located within the moderate-risk flood zone, the reference plane may be established at any level between the flood-resistant construction elevation and a height of five feet above the base plane or curb level, as applicable. While there is a level of flexibility built within the reference plane definition, the reference plane must also be located at or below the first story above flood elevation.
Considering that the owner of such mixed building is proposing to elevate and dry-floodproof the ground floor up to three feet above grade, the first story above flood elevation becomes the finished floor level of the first story located at or above three feet, which is, in this case, the second story. Therefore, the reference plane was able to be situated at five feet above the base plane or curb level, as applicable.
For all flood-resistant buildings, the definition of floor area may be modified in accordance with the provisions of this Section.
(a) Entryways
In all districts, for buildings other than residential buildings with enclosed entryways below the first story above the flood elevation, up to 100 square feet of such entryways may be excluded from the definition of floor area for each foot of difference between the first story above the flood elevation and the level of the adjoining sidewalk, provided such floor space complies with the flood-resistant construction standards for dry-flood-proofing up to the flood-resistant construction elevation or higher. However, no more than a maximum of 500 square feet may be excluded from the definition of floor area for each entryway.
Such exempted floor space shall be considered floor area for the purposes of satisfying other ground floor use regulations of this Resolution, including, but not limited to, limitations on floor area for certain uses, parking wrap and screening requirements, and requirements for floor area at the ground floor.
(b) Modifications to attic allowances for residential buildings
In R2X, R3, R4, R4A, and R4-1 Districts outside of lower density growth management areas, the provisions of paragraph (a) of Section 23-142 (Open space and floor area regulations in R1 and R2 Districts with a letter suffix and R3 through R5 Districts) shall be modified to allow the floor area ratio set forth in the table of such Section to be exceeded by 20 percent provided that any such increase in floor area is located in any portion of a building covered by a sloping roof that rises at least three and one-half inches in vertical distance for each foot of horizontal distance.
(c) Flood-proofed ground floors
(1) For buildings along primary street frontages, or portions thereof, as defined in Section 64-11, floor space located below the first story above the flood elevation and within 30 feet of the street wall along such primary street frontage may be excluded from the calculation of floor area, provided that:
(i) such floor space complies with the flood-resistant construction standards for dry-flood-proofing up to the flood-resistant construction elevation or higher;
(ii) the level of the finished floor of such floor space is located no more than two feet above nor two feet below curb level;
(iii) such floor space shall be limited to non-residential uses other than accessory parking or public parking garages and subject to the minimum depth requirements set forth in Section 37-32 (Ground Floor Depth Requirements for Certain Uses);
(iv) ground floor level street walls shall be glazed in accordance with the provisions set forth in Section 37-34 (Minimum Transparency Requirements); and
(v) for developments, the level of the first story above the flood elevation is 13 feet or more above the level of the adjoining sidewalk.
However, such floor space shall be considered floor area for the purposes of satisfying other ground floor use regulations of this Resolution, including, but not limited to, limitations on floor area for certain uses, parking wrap and screening requirements, and requirements for non-residential floor area at the ground floor.
(2) In all districts, floor space located below the first story above the flood elevation may be excluded from the calculation of floor area provided such floor space complies with the flood-resistant construction standards for wet-flood-proofing up to the flood-resistant construction elevation or higher.
(d) Floor area for existing buildings
For zoning lots containing buildings existing prior to May 12, 2021, as an alternative to the floor area regulations of this Chapter, the amount of floor area allocated to a basement or cellar in such existing building may be determined in accordance with how those terms were defined prior to May 12, 2021.
For zoning lots with flood-resistant buildings, the regulations for yards and open space shall be modified in accordance with the provisions of this Section.
(a) Level of required yards
In all districts, the underlying yard regulations shall be modified to allow the level of a yard or a rear yard equivalent to be located higher than curb level, provided that it does not exceed the flood-resistant construction elevation, and the level set forth by the following regulations:
(1) in Residence Districts, the final grade of front yards and side yards shall not penetrate a plane that begins three feet above curb level at each lot line and has a slope extending perpendicular to lot lines of one foot vertical for each 2 feet 6 inches of horizontal distance;
(2) in Commercial and in Manufacturing Districts, for portions of zoning lots where Sections 33-29 and 43-30 (SPECIAL PROVISIONS APPLYING ALONG DISTRICT BOUNDARIES) apply, the level of front yards and side yards may be permitted to exceed curb level only pursuant to paragraph (a)(1) of this Section.
Nothing in this Section shall be construed so as to permit the creation of spaces below grade on all sides in a manner inconsistent with flood-resistant construction standards.
(b) Permitted obstructions
(1) Covered porches, balconies, and covered access areas
In all districts, a porch or access area covered by a roof or other permanent structure shall be permitted obstructions in any required open space or yard on the zoning lot. Where permanent structures such as balconies are located directly above a porch or access area, such balconies may exceed the width and depth standards of Section 23-13 (Balconies).
(2) Retaining walls
In Residence Districts, retaining walls shall be permitted in front yards and side yards provided any retaining wall parallel to, or within 15 degrees of being parallel to, the street shall not exceed a maximum height of three feet, as measured from the level of the adjoining grade or planted area below such wall, so that no more than three feet of such retaining wall is visible from the street; and
(3) Fences
In Residence Districts, portions of fences located in front yards with height greater than four feet above curb level shall be required to be no more than 50 percent opaque.
(c) Front yard planting requirement
In R1 through R5 Districts, where the distance between the street wall and the street line is 10 feet or less, or for zoning lots with front yards that are shallower than the minimum required pursuant to the applicable district regulations, stairs, ramps or lifts that access the first story above the flood elevation shall be exempted from the area of a front yard for the purpose of calculating the planting requirements of Section 23-451 (Planting requirement).
For all buildings, where the street wall location regulations of this Resolution require the street wall to be located within eight feet of the street line, such regulations may be modified to accommodate exterior stairs and ramps for access to the building, to comply with the requirements of Section 64-50 (Streetscape Regulations), or to provide temporary flood control devices and associated fixtures, as follows:
(a) no street wall need be located closer to the street line than eight feet;
(b) for buildings on zoning lots with a lot width greater than or equal to 50 feet, up to 50 percent of the aggregate width of street walls may be recessed beyond eight feet of the street line, provided that any such recesses deeper than 10 feet along a wide street or 15 feet along a narrow street are located within an outer court and the height of such recess shall not be less than the height of the first story located completely above the level of the adjoining grade; and
(c) for buildings on zoning lots with a lot width of less than 50 feet:
(1) for the first story above the flood-resistant construction elevation, or reference plane, as applicable, and any street wall below such first story, the aggregate width of street wall may be located anywhere; and
(2) for the remaining aggregate width of street walls above such stories, up to 50 percent of the aggregate width of street walls may be recessed beyond eight feet of the street line, provided that any such recesses deeper than 10 feet along a wide street or 15 feet along a narrow street are located within an outer court.
For all buildings where the aggregate width of exterior stairs, ramps, or elevated platforms in front of a street wall exceeds 70 percent or more along the ground floor of the street wall, such stairs, ramps, or elevated platforms shall be screened by living plant material or by the provisions of paragraph (b)(1) of Section 64-521 (Options available for all buildings).
The provisions of this Section, inclusive, are optional, and are only applicable to zoning lots located wholly or partially within flood zones. The provisions of this Section, inclusive, may be applied to zoning lots with cottage envelope buildings. For such zoning lots, the underlying bulk regulations shall apply, except where permitted to be modified by this Section, inclusive.
No building that utilizes the provisions of this Section shall subsequently be enlarged pursuant to Section 73-622 (Enlargements of single- and two-family detached and semi-detached residences).
R3 R4A R4-1
In lower density growth management areas in the districts indicated, the provisions of paragraph (b) of Section 23-142 (Open space and floor area regulations in R1 and R2 Districts with a letter suffix and R3 through R5 Districts) shall be modified to allow the floor area ratio set forth in the table of such Section to be exceeded by 20 percent, provided that any such increase in floor area is located in any portion of a cottage envelope building covered by a sloping roof that rises at least three and one-half inches in vertical distance for each foot of horizontal distance.
R1 R2 R3 R4 R5
In the districts indicated, for zoning lots containing cottage envelope buildings, the following yards, courts and open space regulations may be modified in accordance with the provisions of this Section.
(a) Lot Coverage and Open Space
In R1-2A, R2A, R3-1, R3-2, R4, R4-1, and R4A Districts, the lot coverage and open space regulations need not apply. In lieu thereof, the yard requirements of this Section shall apply.
(b) Front Yards
For buildings that are utilizing the provisions of this paragraph, the provisions of paragraphs (b) and (c) of Section 23-45 (Minimum Required Front Yards) need not apply.
For the purpose of this Section, the area between the street line and the street wall line of adjacent buildings containing residences on the same or adjoining zoning lots fronting on the same street shall be considered adjacent front yards.
Where an adjacent front yard is shallower than the minimum required pursuant to the applicable district regulations, then the front yard of the zoning lot containing cottage envelope buildings may be as shallow as the shallowest adjacent front yard.
(c) Side Yards
The side yard provisions for the applicable district shall apply, except that the required total width of side yards for a zoning lot may be reduced by four inches for each foot by which the width of a zoning lot is less than the minimum widths set forth in the definition of cottage envelope building in Section 64-11 (Definitions). However, in no event shall the required width of a side yard be less than three feet.
In addition, for buildings utilizing the provisions of this paragraph, the provisions of paragraph (c) of Section 23-461 (Side yards for single- or two-family residences) need not apply, provided such open area does not serve as access or contain accessory off-street parking spaces serving existing buildings that remain on the zoning lot, or an adjoining zoning lot.
(d) Rear Yards
(1) Where an interior lot is less than 95 feet deep at any point, the depth of a required rear yard, or portion thereof, for such interior lot, may be reduced by six inches for each foot by which the depth of a zoning lot, or portion thereof, is less than 95 feet. However, in no event shall the minimum depth of a required rear yard, or portion thereof, be reduced to less than 10 feet.
(2) Where a through lot is less than 180 feet deep at any point, the depth of a required rear yard equivalent, or portion thereof, for such through lot, may be reduced by one foot for each foot by which the depth of a zoning lot, or portion thereof, is less than 180 feet. However, in no event shall the minimum depth of a required rear yard equivalent, or portion thereof, be reduced to less than 20 feet.
(e) Corner Lots
Where a corner lot has a lot area equal to or less than 3,000 square feet, only one front yard need be provided, and the remaining front lot line may be treated as a side lot line.
R1 R2 R3 R4 R5
In the districts indicated, all cottage envelope buildings shall be subject to the height and setback provisions set forth in paragraph (b) of Section 23-631 (General provisions), except that:
(a) the maximum height of a perimeter wall of a cottage envelope building before setback shall be 21 feet;
(b) the maximum height of a ridge line shall be 25 feet; and
(c) all heights may be measured from the reference plane.
In addition, the maximum number of stories in any cottage envelope building shall not exceed two stories above the reference plane. For the purposes of this Section, attic space providing structural headroom of less than eight feet shall not be considered a story.
The underlying parking regulations of this Resolution may be modified in accordance with the provisions of this Section inclusive. The provisions of this Section, inclusive, are optional, and are only applicable to zoning lots located wholly or partially within flood zones.
The provisions of Section 64-41 (Special Parking Regulations for All Buildings), inclusive, may be applied to zoning lots regardless of whether buildings or other structures on such zoning lots comply with flood-resistant construction standards.
The provisions of Section 64-42 (Special Parking Regulations for Flood-resistant Buildings), inclusive, may be applied to zoning lots containing flood-resistant buildings, including cottage envelope buildings.
The provisions of this Section, inclusive, are optional, and are only applicable to zoning lots located wholly or partially within flood zones. The provisions of this Section, inclusive, may apply to zoning lots regardless of whether buildings or other structures comply with flood-resistant construction standards. For such zoning lots, the underlying parking regulations shall apply, except where permitted to be modified by this Section, inclusive.
R1 R2 R3 R4 R5
In the districts indicated, other than R4B and R5B Districts, where existing below-grade off-street parking facilities within residential buildings are eliminated and, in compliance with flood-resistant construction standards, are filled in, accessory off-street parking spaces may be relocated from such garages to the side or rear of such buildings, or to the front yard driveway that accessed the former garage, or to a shared driveway along a common side lot line, and such relocated parking spaces need not comply with the underlying parking location, curb cut spacing or permitted obstruction regulations that limit parking, provided that:
(a) no more than two parking spaces may be located in tandem (one behind the other);
(b) each relocated parking space shall have a dimension that conforms with the minimums set forth in Section 25-62 (Size and Location of Spaces); and
(c) where eliminated garages were accessed by a driveway less than 18 feet long, such driveway and curb cut shall be eliminated, and the former driveway planted to the extent necessary to comply, or increase compliance, with the provisions of Section 23-451 (Planting requirement) as if the building on the zoning lot was constructed after April 30, 2008.
Notwithstanding the modifications above, no modification to the maximum number of curb cuts on a zoning lot or the minimum or maximum width of a curb cut, shall be permitted.
In the event that there is no way to arrange relocated required parking spaces on the zoning lot in compliance with the provisions of this Section, given that buildings existing on May 12, 2021, will remain, the Commissioner of Buildings may waive the requirement for such spaces.
Surfacing
R1 R2 R3 R4 R5
In the districts indicated, Section 25-65 (Surfacing) may be modified to allow dustless gravel on all open off-street parking spaces and on portions of driveways beyond the front lot line that access single- or two-family residences on a zoning lot.
The provisions of this Section, inclusive, are optional, and are only applicable to zoning lots located wholly or partially within flood zones. The provisions of this Section, inclusive, may apply to zoning lots containing flood-resistant buildings.
Parking modifications
R1 R2 R3 R4 R5
In the districts indicated, except R4B and R5B Districts, the provisions of this Section shall apply to zoning lots containing single- or two-family residences. For such zoning lots, where off-street parking spaces are required pursuant to Section 25-20 (REQUIRED ACCESSORY OFF-STREET PARKING SPACES FOR RESIDENCES) inclusive, the underlying parking regulations may be modified as follows:
(a) the regulations governing parking location, curb cut location, or permitted obstruction that limit parking need not apply, provided that all parking spaces are either located beneath the first story above the flood elevation within buildings or driveways directly in front of a garage opening. Such spaces shall have a dimension that conforms with the minimums set forth in Section 25-62 (Size and Location of Spaces). However, within lower density growth management areas the provisions of paragraph (c) of Section 25-632 (Driveway and curb cut regulations in lower density growth management areas) shall continue to apply; and
(b) the underlying curb cut spacing regulations for zoning lots existing on May 12, 2021, with a frontage of less than 35 feet along a street need not apply, provided that at least four feet of curb space is provided between a new curb cut and an existing curb cut on the same or an adjacent zoning lot.
Notwithstanding the modifications above, no modification to the maximum number of curb cuts on a zoning lot or the minimum or maximum width of a curb cut, shall be permitted.
All zoning lots utilizing this Section shall comply with the provisions of Section 23-451 (Planting requirement) as if the building on the zoning lot was constructed after April 30, 2008.
STREETSCAPE REGULATIONS
The provisions of this Section, inclusive, shall apply to zoning lots containing flood-resistant buildings, as set forth in paragraphs (b) and (c) of Section 64-12 (Applicability), that have a street wall within 50 feet of the street line in Residence Districts, Commercial Districts and M1 Districts. However, the provisions shall not apply to such buildings containing uses predominantly listed under Use Groups IV(B), IX(B) or X.
All buildings shall provide streetscape mitigation elements in the categories of access or ground floor level, in order to achieve the total points required in the following table. The total points required varies based upon the level of the first story above the flood elevation, as measured from curb level. The individual mitigation options are set forth in Sections 64-51 (Building Access Mitigation Options) and 64-52 (Ground Floor Level Mitigation Options). Cells marked with an “x” designate mandatory categories to fulfill at least one point out of the total points requirement.
The points awarded for compliance with each individual mitigation are set forth in parentheses after the title to each paragraph describing a mitigation element.
For corner lots, the total points requirement set forth in this Section shall apply separately along each street frontage except where the street wall width along one of the street frontages is 25 feet or less, the requirements need only apply to one frontage.
Where zoning lots are required to provide streetscape elements in accordance with other provisions of this Resolution, such elements may also be utilized towards meeting the requirements of this Section, provided that such elements comply with the applicable standard herein.
In addition, all buildings shall meet the requirements set forth in Section 64-53 (Screening Requirements for Parking Within or Below Buildings) as applicable.
Level of the first story above the flood elevation |
Streetscape Mitigation Elements |
Total Points Required |
|
Building Access (Section 64-51) |
Ground Floor Level (Section 64-52) |
||
Below five feet or no first story above the flood elevation |
1 |
||
Five feet or above |
x |
x |
31,2 |
1 Single- and two-family residences on a zoning lot less than 25 feet wide with a first story above the flood elevation at five feet or above need only satisfy a total of two points instead of the three points set forth in the above table.
2 If the requirements of this Section apply to only a portion of the building with a first story above the flood elevation at five feet or above, and such portion of the building does not have a primary entrance, the total points required shall be two, and they need only be satisfied through the ground floor level category.
The streetscape mitigations options of this Section may be applied to all buildings. Where provided as a required streetscape mitigation element, the following shall apply:
(a) Entrance close to grade
(one point)
The primary entrance for the principal use for the building shall be located within two feet of the level of the adjoining sidewalk. However, for mixed buildings in Commercial Districts the primary entrance for the non-residential use on the ground floor shall be located within two feet of the level of the adjoining sidewalk, regardless of whether it is the principal use.
(b) Recessed access
(one point)
Recesses in the street wall shall accommodate the primary entrance to the building, including stairs or ramps to such entrance. However, recesses shall not exceed 50 percent of the aggregate width of street wall for the building.
(c) Wide stairs
(one point)
The primary entrance to a building along the street wall shall include stairs:
(1) with a minimum width of five feet where the aggregate width of street walls of the building is less than or equal to 25 feet; and
(2) with a minimum width of eight feet where the aggregate width of street walls of the building is greater than 25 feet.
In both cases, the run of such stairs shall be oriented perpendicular, or within 15 degrees of being perpendicular, to such primary entrance for at least 50 percent of the height of such stairs.
(d) Covered access
(one point)
The primary entrance to a building shall have a porch or access area covered by a roof or other permanent structure, provided that all structural elements shall have a minimum width or depth of at least three inches. Such roof or other permanent structure shall be located at a minimum height at least eight feet above the finished floor of the primary entrance. In addition, such covering shall have a depth of at least three feet measured perpendicular to the street wall and shall extend along at least 50 percent of the aggregate width of the street wall.
The streetscape mitigations options of this Section may be applied to all single-, two-, or three-family residences. Where provided as a required streetscape mitigation element, the following shall apply:
(a) Porch or landing
(one point)
The primary entrance to a building shall have a porch or landing with a depth of at least three feet and a width that is at least 50 percent of the aggregate width of the street wall. However, such porch or landing need not exceed a width of 25 feet.
(b) Stair turn or stair landing
(one point)
The primary entrance shall be accessed by stairs or ramps that, at a point no higher or lower than two feet from the beginning and end of the stair run, respectively, either change direction in plan or incorporate at least one landing.
The streetscape mitigations options of this Section may be applied to all buildings except single-, two-, or three-family residences. Where provided as a required streetscape mitigation element, the following shall apply:
Multiple entrances
(one point)
Multiple entrances into the building shall be provided, with at least one entrance per every 50 linear feet of street frontage. Fractions equal to or greater than one-half resulting from this calculation shall be considered one entrance.
For the purposes of this Section, where there is a reference to a “blank wall,” the following shall apply:
(a) For manufacturing buildings, the provisions of Type 2 blank walls set forth in Section 37-361 (Blank wall thresholds) shall apply.
(b) For commercial buildings, community facility buildings and mixed buildings, the provisions of Type 3 blank walls set forth in Section 37-361 shall apply.
(c) For residential buildings, the provisions of Type 4 blank walls set forth in Section 37-361 shall apply.
Such blank walls shall be covered by one or more options in Section 37-362 (Mitigation elements) or by options as described in this Section, inclusive. In addition, any surface area of a wall which bounds stairs, ramps, landings, or chair lifts facing a street and that exceeds a height and width of four feet shall constitute a blank wall and comply with the standards of Type 3 blank wall. Such blank wall surfaces shall be calculated between the level of the adjoining sidewalk and the level of the first story above the flood elevation. In addition, any surface area of a wall which bounds stairs, ramps, landings, or chair lifts facing a street and that exceeds a height and width of four feet shall constitute a blank wall and comply with the standards of Type 3 blank wall. Such blank wall surfaces shall be calculated between the level of the adjoining sidewalk and the level of the first story above the flood elevation.
The streetscape mitigations options of this Section may be applied to all buildings. Where provided as a required streetscape mitigation element, the following shall apply:
(a) Surface treatment
(one point)
Surface treatment shall be provided for blank walls in the form of wall treatment, surface texture, or any combination thereof, pursuant to the provisions set forth in paragraphs (a)(1) or (a)(2) of Section 37-362 (Mitigation elements).
If the level of the first story above flood elevation is greater than 10 feet, surface treatment shall only be required to a height of 10 feet above the level of the adjoining sidewalk.
(b) Linear treatment
(one or, where noted, two points)
Linear treatment shall be provided for blank walls in the form of planting, pursuant to the provisions set forth in paragraph (b)(1) of Section 37-362, pursuant to one of the following options below, or any combination thereof. Where the options of this Section are utilized, the percentage requirement associated with the applicable type of blank wall set forth in Section 37-36 (Special Requirements for Blank Walls) shall not apply.
(1) Raised front yards and open space
For residential buildings in Residence Districts where the distance between the street wall and the street line is 10 feet or more, the grade between the street line and blank walls, and their prolongations, shall be elevated above the level of the adjoining sidewalk so that the height of such grade that is midway between the street line and blank walls and prolongations is at least 18 inches above curb level at all points, except for pedestrian ways, vehicular access and off-street parking spaces permitted pursuant to 64-40 (SPECIAL PARKING REGULATIONS). The area with final grade above the level of the adjoining sidewalk shall be greater than 30 percent of the total area between the street line and blank walls and their prolongations.
Raised front yards and open spaces shall be planted in accordance with applicable planting requirements in this Resolution.
This option shall satisfy two points if the area with final grade above curb level is greater than 50 percent of the total area between the street line and blank walls and their prolongations.
(2) Terraced front yards and open spaces
For residential buildings in Residence Districts, terraced planting areas shall be provided. The retaining walls of such areas shall not be less than an average height of three feet and exceed an average height of six feet, as measured from the level of the adjoining sidewalk below such wall, and the retaining wall closest to the street line shall not exceed a height of three feet. The area with the retaining walls shall be greater than 30 percent of the total area between the street line and blank walls and their prolongations. Planting shall also be provided for at least 50 percent of the linear footage above and below the retaining walls, through a combination of perennials, annual flowers, decorative grasses or shrubs.
This option shall satisfy two points if the area with the retaining walls is greater than 50 percent of the total area between the street line and blank walls and their prolongations.
The streetscape mitigations options of this Section may be applied to all single-, two-, or three-family residences. Where provided as a required streetscape mitigation element, the following shall apply:
(a) Transparency
(one point)
Transparent glazing materials shall occupy at least 20 percent of the surface area of the street wall of the ground floor, measured between a height of two feet and 10 feet, or the height of the ground floor ceiling, whichever is higher, as measured from the adjoining sidewalk.
(b) Additional fenestration
(one point)
In addition to the primary entrance, one or more doors, including garage doors, shall be provided.
The streetscape mitigations options of this Section may be applied to all buildings except single-family, two-family, or three-family residences. Where provided as a required streetscape mitigation element, the following shall apply:
(a) Transparency with use
(one point)
One or more of the following options may apply:
(1) Lobby
(one point)
In all districts, a lobby that complies with the standards of Type 1 lobbies set forth in Section 37-33 (Maximum Width of Certain Uses), shall be provided. Transparent glazing materials shall occupy at least 40 percent of the surface area of the street wall of the lobby, measured between a height of two feet and 10 feet, or the height of the ground floor ceiling, whichever is higher, as measured from the adjoining sidewalk.
(2) Community facilities and accessory residential uses
(one point)
In all districts, for buildings containing residences with three or more dwelling units, at least 50 percent of the ground floor level street wall shall be allocated to accessory residential uses other than accessory off-street parking, or community facilities uses, including, but not limited to, recreation space or bicycle storage, that extends to a minimum depth of 15 feet from the street wall. Transparent glazing materials shall occupy at least 40 percent of the surface area of the street wall of such uses, measured between a height of two feet and 10 feet, or the height of the ground floor ceiling, whichever is higher, as measured from the adjoining sidewalk. Where the spaces for such uses need not be fully enclosed, decorative screening or latticework may be substituted for transparent glazing materials.
(3) Non-residential uses
(one point)
In Commercial Districts, uses on the ground floor level, to the minimum depth set forth in Section 37-32 (Ground Floor Depth Requirements for Certain Uses), shall be limited to non-residential uses, except for Type 2 lobbies and entrances and exits to accessory parking spaces provided in accordance with Section 37-33. Ground floor level street walls shall be glazed in accordance with Section 37-34 (Minimum Transparency Requirements) except that the transparent materials may begin higher than 2 feet, 6 inches, above the level of the adjoining sidewalk.
If group parking facilities are provided, they shall be wrapped by floor area, in accordance with paragraph (a) of Section 37-35 (Parking Wrap and Screening Requirements).
(b) Transparency close to grade
(one point)
In all districts, transparent materials provided to satisfy street wall transparency requirements shall not begin higher than 2 feet, 6 inches above the level of the adjoining sidewalk. The floor level behind such transparent glazing materials shall not exceed the level of the window sill for a depth of at least four feet, as measured perpendicular to the street wall.
(c) Linear treatment
(one point)
Linear treatment shall be provided for blank walls in the form of benches, bicycle racks, tables and chairs, or any combination thereof, as set forth in paragraph (b) of Section 37-362 (Mitigation elements).
The provisions of this Section shall apply to all buildings other than:
- single or two-family residences; and
- buildings containing uses predominantly listed under Use Group IV(B), IX(B) or X.
Where the first story above the flood elevation is five or more feet above curb level and the street wall of a building is within 50 feet of the street line, for any level where off-street parking is provided within or below a building, such parking shall be either wrapped by floor area or screened pursuant to the provisions of Section 37-35 (Parking Wrap and Screening Requirements).
Buildings in existence prior to May 12, 2021, shall not be altered in any way that will create a new non-compliance or increase the degree of non-compliance with the provisions of this Section.
The provisions of this Section, inclusive, are optional, and may be applied to buildings with non-conforming uses, or to non-complying buildings or other structures, as applicable, that are also flood-resistant buildings.
For all buildings with non-conforming uses, the provisions of Sections 52-20 (REPAIRS OR ALTERATIONS), 52-40 (ENLARGEMENTS OR EXTENSIONS), and 52-50 (DAMAGE OR DESTRUCTION), inclusive, shall be modified to allow a non-conforming use to be continued, and a building with non-conforming uses to be altered, enlarged, relocated or reconstructed to comply with flood-resistant construction standards, pursuant to the provisions of this Section, inclusive.
Where a building with non-conforming uses is also non-complying with the applicable bulk regulations, non-compliances may be continued, increased or newly created only in accordance with the provisions of Section 64-612 (Special floor area regulations for buildings with non-conforming uses), Section 64-613 (Special height regulations for buildings with non-conforming uses), and Section 64-614 (Process for establishing non-conforming uses), except that Section 64-622 (Special open area regulations for non-complying buildings) and Section 64-624 (Process for establishing non-compliances) may also apply.
In addition, damage and destruction provisions set forth in Section 64-611 (Special regulations for damage or destruction provisions for buildings with non-conforming uses) shall apply to such buildings.
The provisions set forth in Sections 52-53 (Buildings or Other Structures in All Districts) and 52-54 (Buildings Designed for Residential Use in Residence Districts) shall be modified to allow all buildings containing non-conforming uses to be reconstructed, provided that:
(a) for non-conforming single- and two-family residences in Residence Districts and Commercial Districts, except C8 Districts, such reconstruction may exceed 75 percent of the total floor area of the building;
(b) for non-conforming single- and two-family residences in C8 Districts or Manufacturing Districts, such reconstruction may exceed 75 percent of the total floor area of the building provided that 25 percent or more of the aggregate length of the block frontage on both sides of the street facing each other is occupied by zoning lots containing residential or community facility uses;
(c) for all other buildings with non-conforming uses, the extent of reconstructed floor area shall not exceed 75 percent of the total floor area of the building.
The maximum amount of non-conforming floor area in the altered, enlarged, relocated or reconstructed building shall not exceed the amount of non-conforming floor area existing prior to the alteration or reconstruction work.
The maximum height of such altered, enlarged, relocated or reconstructed building with non-conforming uses, shall not exceed the maximum height permitted by the applicable district regulations, except that for non-conforming residences in C8 Districts or Manufacturing Districts, the maximum height of such altered, enlarged, relocated or reconstructed building, shall comply with one of the following options:
(a) for single or two-family residences, a horizontal plane equivalent to a height of 35 feet, and for buildings other than single- or two-family residences, the applicable sky exposure plane for the district; or
(b) for all residences a horizontal plane equivalent to the pre-existing height of such building, as measured from the top of the lowest usable floor, to the highest point of such pre-existing building, as measured from the reference plane.
For all buildings with non-conforming uses utilizing any of the provisions of this Section, the amount of pre-existing non-conforming floor area and pre-existing non-compliances, as applicable, shall be based either on construction documents for such building that were previously approved by the Department of Buildings at the time of construction, enlargement, or subsequent alteration, as applicable, of the building or, where an approved set of construction documents does not exist for such building, an as-built drawing set completed by a professional engineer or architect. The Department of Buildings may request additional information to substantiate proof of non-conformances and non-compliances, as applicable. Verification by the Department of Buildings of such documentation shall be a pre-condition prior to any demolition for reconstruction work, or alteration permit issued by the Department of Buildings for a zoning lot altering or reconstructing buildings with non-conforming uses and non-compliances, as applicable, pursuant to the provisions of this Section.
For all non-complying buildings or other structures, the provisions of Sections 54-20 (REPAIRS OR ALTERATIONS), 54-30 (ENLARGEMENTS OR CONVERSIONS), and 54-40 (DAMAGE OR DESTRUCTION IN NON-COMPLYING BUILDINGS), inclusive, shall be modified to allow a non-compliance to be continued, and such non-complying building or other structure to be altered, enlarged, relocated or reconstructed to comply with flood-resistant construction standards, subject to the permitted thresholds of Sections 54-41 (Permitted Reconstruction) and 54-42 (Use of Alternate Formula), and the provisions of this Section.
In addition, such altered, enlarged, relocated or reconstructed building or other structure may create a new non-compliance with, or increase the degree of existing non-compliance with the applicable bulk regulations for the district, subject to the applicable provisions of this Section, inclusive.
For buildings with non-complying floor area, the maximum amount of floor area in the altered, enlarged, relocated or reconstructed building shall not exceed the amount of pre-existing floor area, nor shall it exceed the maximum floor area permitted by the applicable district regulations by more than 20 percent. In addition, subsequent to such alteration, enlargement, relocation or reconstruction, no extension or change of use may create a new non-compliance or increase the degree of existing non-compliance with floor area.
The following provisions may apply to non-complying buildings or other structures.
(a) Relocation allowances
Non-complying buildings or other structures may continue an existing non-compliance, increase the degree of an existing non-compliance, or create a new non-compliance with yards, open space, open space ratio, lot coverage, courts, minimum distances between two or more buildings, or minimum distances between legally required windows and walls or lot lines, in order to relocate or alter the footprint of the building, provided that:
(1) the resulting lot coverage shall be less than or equal to that of the pre-existing building or other structure as it existed prior to the alteration, enlargement, relocation or reconstruction work or the amount permitted by the district, as applicable, whichever is greater, except that, where the provisions of paragraph (b) of this Section are utilized, the first story above the flood elevation and any stories below, may be exempted from such calculation;
(2) a new or increased non-compliance into an open area shall not exceed a horizontal distance of five feet, as measured perpendicular to the outermost edge of the non-complying building or other structure, as it existed prior to the alteration, enlargement, relocation or reconstruction work, except that such limitation shall not apply:
(i) where the pre-existing building or other structure is located either partially or entirely seaward of the shoreline, and such building or other structure will be altered, enlarged, relocated or reconstructed to be repositioned landward of the shoreline on the same zoning lot; or
(ii) where additional distance is necessary to accommodate access, including stairs, ramps or lifts in a required yard, provided that any additional encroachment is limited to the depth of such access;
(3) any new or increased non-compliance shall not result in an open area of:
(i) less than five feet between the wall of a building or other structure and a rear lot line;
(ii) less than three feet between the wall of a building or other structure and a front lot line, in districts with front yard requirements; and
(iii) three feet between the wall of a building or other structure and a side lot line for detached buildings in districts that do not allow zero lot line buildings; and
(4) the height of buildings or other structures within non-complying yards or open space, as measured from the reference plane, shall not exceed the height set forth in paragraph (a) of Section 64-623 (Special height regulations for non-complying buildings).
(b) Allowances for horizontal expansions
The first story above the flood elevation and stories located below such story, may create a new non-compliance with, or increase the degree of existing non-compliance with the applicable rear yards, open space, open space ratio, or lot coverage regulations for the district, provided that:
(1) the increased lot coverage does not exceed an additional 20 percent of such lot coverage permitted by the underlying regulations in R1-2A, R2A, R3-1, R3-2, R4, R4B, R5, R5B, and R5D Districts;
(2) the increased lot coverage does not exceed an additional 20 percent of the maximum footprint permitted by applying the applicable district rear, side and front yard regulations in R2X, R3A, R3X, R4-1, R4A, and R5A Districts;
(3) for single- or two-family residences, the encroachment into a rear yard does not result in a rear yard with a depth of less than 20 feet; and
(4) in all districts, the encroachment into a required open area does not exceed a height of 15 feet, as measured from the first story above the flood elevation.
Nothing in this Section shall affect the permitted obstruction allowances set forth by the district regulations.
For buildings or other structures that are non-complying with the applicable district height and setback regulations, the maximum height of such altered, enlarged, relocated or reconstructed building or other structure, shall not exceed the height permitted pursuant to either paragraph (a) or (b) of this Section, as applicable. An alteration, enlargement, relocation or reconstruction pursuant to this Section may continue an existing non-compliance, increase the degree of an existing non-compliance, or create a new non-compliance with height and setback regulations, and may continue or increase a non-compliance with other bulk regulations associated with such non-complying height, subject to the limitations of this Section. All permitted obstruction allowances shall be measured with respect to the modified envelopes of this Section.
(a) For pre-existing buildings or other structures that do not exceed the overall permitted height
Where the height of a pre-existing building or other structure does not exceed the overall height permitted by the applicable district regulations, as measured from the top of the lowest usable floor to the highest point of such pre-existing building, the height of such altered, enlarged, relocated or reconstructed building or other structure shall not exceed:
(1) the applicable sky exposure plane, for buildings governed by sky exposure planes as measured from the reference plane; or
(2) a horizontal plane equivalent to the maximum building height permitted by the applicable district for all other buildings as measured from the reference plane.
(b) For pre-existing buildings or other structures that exceed the overall permitted height
Where the height of a pre-existing building or other structure exceeds the overall height permitted by the applicable district regulations, as measured from the top of the lowest usable floor to the highest point of such pre-existing building:
(1) the height of such altered, enlarged, relocated or reconstructed building or other structure as measured from the reference plane shall not exceed a horizontal plane equivalent to the pre-existing height of such building, as measured from the top of the lowest usable floor, to the highest point of such pre-existing building, provided also that such height shall not exceed the overall height permitted by the applicable district regulations by 10 percent, or 10 feet, whichever is less; and
(2) for single or two-family residences in R1-2A, R2A, R2X, R3, R4, R4-1, R4A, or R5A Districts, where the degree of the alteration or reconstruction exceeds 75 percent of the floor area, the height of a perimeter wall of such altered, enlarged, relocated or reconstructed building or other structure as measured from the reference plane shall not exceed the higher of the maximum perimeter wall height for the district, or the pre-existing height of such perimeter wall, as measured from the top of the lowest usable floor to the highest point in such pre-existing building before setback.
However, the height allowances of this Section shall not apply to single or two-family residences that are not non-complying with floor area requirements, or where the provisions of paragraph (b) Section 64-622 (Special open area regulations for non-complying buildings) are utilized.
For all non-complying buildings or other structures utilizing any of the provisions of this Section, the amount of pre-existing non-compliances shall be based either on the construction documents of such building or other structure previously approved by the Department of Buildings at the time of construction, enlargement, or subsequent alteration of such building or other structure, as applicable, or, where an approved set of construction documents does not exist for such building or other structure, an as-built drawing set completed by a professional engineer or architect. The Department of Buildings may request additional information to substantiate proof of non-compliances. Verification by the Department of Buildings of such documentation shall be a pre-condition prior to any demolition for reconstruction work, or alteration permit issued by the Department of Buildings for a zoning lot altering or reconstructing non-compliances pursuant to the provisions of this Section.