5.11

No building or structure shall be built nor shall any existing building or structure be enlarged which does not conform to the regulations as to maximum ratio of floor area and lot areas, minimum dimensions of front, side, and rear yards and maximum height of structures, in the several districts as set forth in Article 5.000, Section 5.30 except as hereinafter provided and except in the Cambridge Center MXD District, which shall be governed by the requirements of Section 14.30.

5.12

The lot or yard areas required for any new building or use may not include any part of a lot that is required by any other building or used to comply with any requirements of this Ordinance, nor may these areas include any property of which the ownership has been transferred subsequent to the effective date of this Ordinance if such property was a part of the area required for compliance with the dimensional requirements applicable to the lot from which such transfer was made.

5.13

In the case of multiple buildings on a lot that do not contain Residences as listed in Section 4.31 a-j., the minimum distance between such buildings shall not be less than the sum of the heights of the buildings divided by six or ten feet, whichever is greater. In determining compliance with this section, portions of buildings exempted by Section 5.23 shall not be counted in computing building height.

5.14

[Deleted]

5.15

No lot or development parcel shall be changed in size, shape, or ownership so that the dimensional requirements or off-street parking and loading requirements prescribed in this Ordinance are no longer satisfied. This paragraph shall not apply where a portion of the lot or development parcel is acquired for a public purpose.

5.16

Any new building or new addition to a building that receives a building permit or, where applicable, a special permit after the enactment of this Section shall require certification from DPW that it conforms to the Flood Resilience standards set forth in Section 22.80 of this Zoning Ordinance before issuance of a building or special permit if it meets the following criteria:

(a)

The new building or addition involves the construction of a new foundation, and

(b)

In the case of an addition to an existing building, the footprint area of the building, measured in plan view, is increased by at least 50%.

(Ord. No. 2022-9, 2-27-2023; Ord. No. 2025-1, 2-10-2025)

5.21

Lot area and width.

5.21.1

There shall be no required minimum lot area or width except as set forth below.

5.21.2

No building shall be erected on a lot which does not have at least twenty (20) feet of frontage on a street. This paragraph does not apply to subdivided lots within a townhouse development that have a combined lot frontage of at least twenty (20) feet. This requirement shall not be applicable in the Cambridge Center MXD District.

5.22

Open Space. Where a new building is constructed on a lot or where the footprint of an existing building is enlarged, the lot shall conform to the Open Space Ratio required in the zoning district. The total Open Space on the lot shall be the sum of all areas that meet the definition and standards for at least one of the following types of Open Space: Private, Public, Publicly Beneficial, Green Area, or Permeable Open Space. All five terms are defined in Article 2.000 and additional standards are set forth below. Areas that meet the definition of more than one type of Open Space shall only be counted once when calculating the total Open Space on the lot. The Open Space Ratio on a lot shall be the total Open Space area divided by the lot area, expressed as a percentage.

5.22.1

Private Open Space. Private Open Space shall be open and unobstructed to the sky, except that up to fifty (50) percent of the total Private Open Space may be Shaded Area. Trees, plantings, arbors, fences, flagpoles, sculpture, fountains and recreational and drying apparatus and similar objects shall not be considered obstructions when located within a private open space. Objects or structures intended exclusively for bicycle parking, designed and located in accordance with Section 6.100, which may be uncovered, partially covered or fully enclosed, shall not be considered obstructions provided that such objects or structures are not used for motor vehicle parking, general storage or any other use, and further provided that any such structure exceeding six feet (6') in height conforms to the requirements for an accessory building in Section 4.21. Beehives and apiaries conforming to the Standards for Urban Agriculture in Article 23.000 of this Zoning Ordinance shall not be considered obstructions provided that they are no more than six (6) feet in height. Structures or features that are necessary for a building to comply with the Flood Resilience Standards in Section 22.80, such as stairs, ramps, or window wells, shall not be considered obstructions. To the extent permitted in this Ordinance, balconies and roof areas may also be considered as Private Open Space. Private Open Space shall include areas that are shared by all building occupants or available to occupants of separately tenanted areas of a building, such as dwelling units. Private Open Space may include either hardscaped or permeable areas but may not have a slope greater than ten percent (10%). Private Open Space must meet the following other dimensional characteristics:

a.

If located at grade, Private Open Space must have both a width and a length of at least fifteen (15) feet and may be shared by all occupants of a building or divided into areas that are accessed separately.

b.

If located above grade, such as balconies, decks, and roofs of garages and buildings, and shared by all occupants of a building, Private Open Space must have both a width and a length of at least six (6) feet and have a minimum area of seventy-two (72) square feet.

c.

If located above grade or partially below grade and accessible to separately tenanted spaces, such as balconies and decks or lower-level patios, Private Open Space must have a width and length of at least three (3) feet and have a minimum area of twenty (20) square feet.

5.22.2

Public Open Space. Public Open Space shall be open and unobstructed to the sky, except that up to fifty (50) percent of the total Public Open Space may be Shaded Area. Public Open Space may include but is not limited to lawns, decorative plantings, interior walkways, abutting sidewalks, active and passive recreation areas, playgrounds, fountains, and public performance areas. Public Open Space shall not include rooftop areas, patios, balconies, parking lots, or driveways. Limited paved surfaces may be designed to accommodate occasional use by motor vehicles servicing the park facility. If the facility is not held in fee simple by the City of Cambridge or other public entity, the Public Open Space may be land remaining in private ownership but protected for public use by means of a permanent easement, conservation restriction, or other similar legal device acceptable to the City.

5.22.3

Publicly Beneficial Open Space. Such space shall be customarily available or shall be readily visible to such occupants and visitors, though physically inaccessible, by being located and treated to enhance the amenity of the development through a general appearance of openness. Publicly beneficial open space shall include parks, plazas, lawns, landscaped areas, decorative plantings, and active and passive recreational areas. Publicly beneficial open space shall also include loggias, atriums, arcades and pedestrian ways listed and defined in Section 14.45. Streets, parking lots, driveways, service roads, loading areas, and areas normally inaccessible to pedestrian circulation beneath pedestrian bridges, decks, or shopping bridges shall not be counted in calculating publicly beneficial open space.

5.22.4

Green Area Open Space. Green Area Open Space shall be open and unobstructed to the sky except that up to fifty (50) percent of the total required Green Area Open Space may be Shaded Area. Green Area Open Space shall be land at grade and shall consist of friable, permeable materials (including but not limited to loam, gravel, sand, crushed stone, and including naturally occurring soil, bedrock, and incidental pipes and other underground utilities) having a minimum depth of three (3) feet. Said land shall be capable of supporting the growth of trees, grass, ground cover, shrubs, and similar vegetation. Such area may not include any portion of the lot used for parking areas and access drives or other hard surface areas, except walks and terraces designed and intended for non-motor vehicle use.

Green Area Open Space shall consist entirely of living trees, grass, ground cover, bushes, shrubs, and/or similar vegetation, as well as water and other natural features of the site. However, in no case shall hard surfaced walks and terraces, or pervious ground covers like gravel, stone, and wood chips not being used as mulch beneath vegetation, exceed twenty-five (25) percent of the total area counted as Green Area Open Space.

5.22.4(a)

Permeable Open Space. Permeable Open Space shall consist of a surface material that may include vegetation; rocks, pebbles, wood chips and similar landscaping materials; or unit pavers. All other materials (for example, continuously poured asphalt or concrete) are not allowed except that any material may be used for pedestrian walkways not exceeding 5 feet in width or half the width of the area in which they are located, whichever amount is less.

5.22.5

Green Factor. Where any new building, new addition to a building that seeks to increase the footprint of a building by at least 50% in area, or new surface parking area is created on or after the enactment of this Section, the lot or Development Parcel shall be designed to conform to the Green Factor Standard set forth in Section 22.90 of this Zoning Ordinance before issuance of a building permit or special permit if applicable.

5.23

Building Height and Stories Above Grade.

5.23.1

Height Exceptions. The provisions of this Ordinance governing the height of buildings and structures in all districts shall generally not apply to the following:

(a)

chimneys, water towers, air conditioning equipment, elevator bulkheads, skylights, ventilators and other necessary features appurtenant to buildings which are usually carried above roofs and are not used for human occupancy;

(b)

domes, towers, or spires above buildings if such features are not used for human occupancy and occupy less than ten percent (10%) of the lot area;

(c)

wireless or broadcasting towers and other like unenclosed structures which occupy less than ten percent (10%) of the lot area;

(d)

Wind Turbines, subject to the requirements and limitations set forth in Section 22.70;

(e)

elements of a Solar Energy System, as defined in Section 22.60 of this Zoning Ordinance, that would ordinarily be located on a rooftop where they would have direct exposure to sunlight;

(f)

beehives and apiaries extending no more than six (6) feet above a rooftop, in accordance with the Standards for Urban Agriculture in Article 23.000 of this Zoning Ordinance; and

(g)

structures appurtenant to Green Roof Area or usable outdoor space adjacent to a Green Roof Area, including but not limited to elevator and stair access headhouses and Shade Canopies located above the roof, provided that the area of such features is less than the total adjacent Green Roof Area.

5.23.1.1

Building elements enumerated in (a) and (g) above shall be limited in height where they are placed on a building located in a non-residential district, which district abuts a Residence C-1, C-1A, C-2, C-2A, C-2B district. In these instances, the following height limitations shall apply to those building elements:

(a)

The elements must be below one or more forty-five (45) degree bulk control planes. Each bulk control plane shall begin, in the vertical dimension, at the maximum height limit permitted in the non-residential zoning district. In the horizontal dimension, the plane shall begin at the residential/non-residential zoning district line: however, where that line lies within a street, the plane shall begin at the front lot line, located nearest the zoning district line, of the lots on which the building is sited. Thereafter the bulk control plane shall rise from its beginning over the non-residential zoning district. (See illustrative figure 5.23)

(b)

The limitations in Paragraph 1 above may be waived by special permit from the Planning Board upon a finding by the Board that the additional height is necessary. In making that determination the Planning Board shall consider the special and unique requirements of the use that the elements are serving, any special constraints imposed by the site upon which the building is located, the nature and character of development in the adjacent residential district, and the extent to which successful efforts are made to minimize the visual and acoustical impact of the elements on neighbors.

5.23.2

If the Ground Story of a building is elevated to meet the Flood Resilience Standards in Section 22.80 of this Zoning Ordinance, then the allowed height of buildings and structures as set forth in this Zoning Ordinance may be increased as-of-right to compensate for the difference between the Ground Story finished floor elevation and the Grade elevation. However, the allowed increase in height shall be no greater than the difference in elevation between the 1%-Probability Long-Term Flood Elevation as described in Section 22.80 and the Grade, or four (4) feet, whichever is less. The City Engineer shall certify that the Flood Resilience Standards in Section 22.80 are met prior to issuance of a building permit for a building or structure utilizing the provisions of this Section 5.23.2.

5.23.3

Application of Height Limits to Residential and Non-residential Uses. This Section explains how the height limits in the Table of District Dimensional Regulations in Section 5.30 apply.

(a)

Buildings or portions of buildings used as Residences, listed in Section 4.31 a-j of this Zoning Ordinance, or Religious Purposes uses, listed in Section 4.33 a, are generally limited by the maximum number of Stories Above Grade and by the maximum building height above grade in feet, which is intended to enable the allowed number of Stories Above Grade while limiting excessive story height. Where there is no explicit limit on Stories Above Grade, including but not limited to special districts, overlay districts, or PUD districts, any number of Stories Above Grade shall be permitted within the applicable height limit.

(b)

Buildings or portions of buildings used for any uses other than those listed in Section 4.31 a-j or Section 4.33 a of this Zoning Ordinance shall be considered non-residential and subject to the non-residential height limitations of the zoning district.

(c)

In a mixed-use building containing both residential (as described in Paragraph (a) above) and non-residential (as described in Paragraph (b) above) uses, the limit on Stories Above Grade shall apply to the entire building. Portion(s) of the building devoted to uses described in Paragraph (b) above shall not be located above the non-residential height limit. Portion(s) of the building devoted to uses described in Paragraph (a) above may exceed the non-residential height limit but shall not exceed the residential height limit.

5.24

Yards.

5.24.1

Every part of a required yard shall be open to the sky and unobstructed, except that the following features may be located within a required yard:

(a)

Awnings, arbors, fences, flagpoles, recreational, and laundry drying equipment and similar objects;

(b)

Objects or structures intended exclusively for bicycle parking meeting the requirements of Article 6.000, which may be uncovered, partially covered or fully enclosed, provided that such objects or structures are not used for motor vehicle parking, general storage or any other use, and further provided that any such structure exceeding six feet (6') in height conforms to the requirements for an accessory building in Section 4.21;

(c)

Beehives, apiaries, henhouses, and hen runs conforming to the Standards for Urban Agriculture in Article 23.000 of this Zoning Ordinance;

(d)

Objects or equipment located in a required yard that are necessary for or appurtenant to a Public Bicycle-Sharing Station;

(e)

Open or lattice-enclosed fire escapes for emergency use only;

(f)

Projecting eaves, chimneys, bay windows, balconies, open fire escapes and like projections which do not project more than three and one-half (3½') feet and which are part of a building not more than thirty-five (35') feet in height or more than thirty-five (35') feet in height if portions of the building above that height contain residential uses listed in Section 4.31 a-i.;

(g)

Shade Canopies as defined in this Zoning Ordinance, provided that any Shade Canopy exceeding seven feet (7') in height shall be set back at least five feet (5') from a side or rear lot line in a residential district; and

(h)

Exterior steps, ramps, elevated walkways, porches, window wells, flood barriers, and other elevated features that provide protection or resilience from flooding on the lot, provided such features do not project more than twelve (12') feet beyond the line of the foundation wall of a building, are open to the air and are either unroofed or covered only by a Shade Canopy, and are not elevated higher than four (4') feet above Grade or the 1%-Probability Long Term Flood Elevation as determined by the Flood Resilience Standards in Section 22.80 of this Zoning Ordinance, whichever is higher.

(i)

Any required flood water retention systems or related facilities for lots subject to Floodplain Overlay District regulations in Section 20.70 of this Zoning Ordinance.

5.24.2

Existing conforming or pre-existing non-conforming buildings in existence prior to August 2, 2010, may encroach or further encroach into a required yard solely in order to install exterior insulation to an existing exterior wall, provided that such existing exterior wall is not moved or demolished except to remove and replace its exterior wall covering and that the requirements of either Paragraph (a) or Paragraph (b) below are met:

(a)

The yard is not decreased by more than eight (8") inches from the pre-existing condition, the wall itself does not intrude more than eight (8") inches further into the existing yard, and the outer plane of the exterior wall after the installation of exterior insulation and exterior wall covering is not closer than three (3') feet to the nearest property line; or

(b)

The Board of Zoning Appeal (BZA) has granted a special permit to exceed the limitations of Paragraph (a) above upon finding that, given the unique physical constraints of the building or the site, such relief is necessary to install exterior insulation that will substantively improve the thermal performance of the exterior wall envelope, that potential impacts to the safety or privacy of abutting uses will be mitigated, and that the general criteria set forth in Section 10.43 of this Zoning Ordinance are met.

5.24.3

On lots abutting streets on more than one side, the front yard requirements of each of the abutting streets shall apply regardless of designated front lot lines. Any remaining sides shall be subject to side yard requirements.

5.24.4

Measurements for minimum yards which are determined by formula shall be made in the following manner:

(1)

"H" is the height of the building. "L" is the length of the wall measured parallel to the corresponding lot or street line. The front yard is measured from the street line, or building line where such has been established, except where otherwise indicated herein. For buildings of forty (40') feet or less in height the denominator in the yard formulas in the Tables in Section 5.30 may be increased by two subject to the minimum yard requirements set forth in footnotes a, b and c of Tables 5-1 and 5-2.

(2)

Where a building consists of various roof levels an average height, or "H", may be used in the required yard formula. Average height is determined by adding the products of the height of each roof level facing the given lot line, (H1, H2, etc.) times the length of each roof level (L1, L2, etc.) and dividing the sum by the sum of the length of the levels (L1, L2, etc.) (see formula below)

(3)

Where a building presents a variety of vertical planes to any given lot or street line, no plane shall be closer to the street or building line or lot line than permitted by the application to such plane of the appropriate formula in the tables of dimensional requirements in Section 5.30. For all planes set forward of the setback line required by said tables for the building if it were constructed in a single vertical plane, other planes must be set behind the setback line so calculated. The result shall be that the sum of the products of the setback required for each plane times the facing area of each plane respectively shall be at least as great as the product of the setback required by the appropriate table for the building if it were constructed in a single vertical plane times the facing area of the building if viewed as a single plane. (See illustration below):

The product of (setback 1 x facing area 1) + (setback 2 x facing area 2) MUST EQUAL OR EXCEED the product of (single plane setback) x (single plane facing area).

5.25

Gross Floor Area (GFA) and Floor Area Ratio (FAR).

5.25.1

Gross Floor Area shall include:

(a)

Roofed porches and balconies that are enclosed on more than fifty percent (50%) of their perimeter and do not meet the definition of Shaded Area;

(b)

Unroofed porches and balconies above the third floor except as provided in Section 5.25.2(j);

(c)

Elevator shafts and stairwells on each floor, not excluded in Section 5.25.2(c) or (f);

(d)

Attic space, whether finished or unfinished, within the area of a horizontal plane that is five (5) feet above the attic floor and which touches the side walls and/or the underside of the roof rafters and which is not excluded in Section 5.25.2(f);

(e)

Interior balconies, mezzanines, and penthouses, and the area of each floor level of any interior courtyard in a building with more than two floors, whether or not covered by a roof, which has a minimum dimension of less than forty (40) feet in any direction unless twenty (20) percent or more of the perimeter of such courtyard at each floor level measured consecutively is not enclosed;

(f)

Area of parking facilities in structures except as excluded in 5.25.2(b); and

(g)

Any accessory parking spaces not in above ground structures if in excess of the maximum number permitted on the premises as set forth in Section 5.25.3 and 6.30.

5.25.2

Gross Floor Area shall not include:

(a)

Areas used for off street loading purposes;

(b)

Area of parking facilities in structures located underground and the area of on grade open parking spaces outside the building footprint at or below the maximum number permitted on the premises as set forth in Sections 5.25.3 and 6.30;

(c)

Area in Stories Below Grade that meets at least one of the following criteria:

(i)

The area has less than seven feet (7') of ceiling height measured from the floor to the line of the bottom of the floor joists above, or to any subfloor or finished surface above any floor joists that are spaced not less than four (4) feet on center; or

(ii)

The area is designed in accordance with the Flood Resilience Standards set forth in Section 22.80 of this Zoning Ordinance.

(d)

Open and lattice-work fire escapes;

(e)

Unroofed porches and balconies no higher than the third floor;

(f)

Areas located in any part of a building or site devoted to elevator machinery or mechanical equipment necessary for the operation and maintenance of the building, including heating and cooling equipment, electrical and telephone facilities, fuel storage, and sustainable mechanical systems and related equipment and chases for systems including, but not limited to, solar energy systems, geothermal systems and heat pumps, solar hot water systems and related tubes and tanks, equipment related to radiant heating, hydronic cooling, heat recovery ventilators, and energy recovery ventilators;

(g)

Elevator shafts and stairwells on floors where there is no other area which qualifies to be included in Gross Floor Area, including headhouses that provide access to Green Roof Area;

(h)

Attic space not included in Section 5.25.1(d);

(i)

Bicycle parking meeting or exceeding the requirements of Article 6.000, which shall include all areas occupied by Bicycle Parking Spaces and access routes intended exclusively for use by bicycles, which shall be clearly indicated in the bicycle parking plan requirements set forth in Section 6.52.1 whether located in a principal use structure, any parking facility for motor vehicles, or in an accessory structure;

(j)

Green Roof Area as defined in this Zoning Ordinance and constructed in accordance with the standards in Section 22.30 of this Zoning Ordinance, whether or not it meets the minimum Green Roofs Requirement in Section 22.35, as well as the area of adjacent impervious walkways, decks, and access headhouses intended for maintenance or enjoyment of the Green Roof Area, provided that such area is not greater than the Green Roof Area;

(k)

Interior air spaces within a Double-Skin Façade as defined in Article 2.000 of this Zoning Ordinance, up to a maximum depth of one (1) foot, provided the space is not to be accessed except for maintenance purposes;

(l)

Insulating material attached to the exterior of the structural elements of an external building wall;

(m)

Shaded Area as defined in this Zoning Ordinance;

(n)

Public Bicycle-Sharing Stations.

5.25.3

FAR Exceptions for Parking and Loading Facilities.

5.25.3.1

Loading Facilities. Areas used for off-street loading purposes shall be exempt from the requirements as to Floor Area Ratio but shall conform to all other requirements of the district in which it is located.

5.25.3.2

Parking Facilities in Structures. The floor area of an underground parking garage and the floor area of the underground portion of a structure devoted in whole or in part to parking automobiles, shall not be counted as Gross Floor Area and shall be exempt from the requirements as to floor area but shall conform to all other requirements of the district in which it is located. All other parking in structures shall be subject to the requirements as to Floor Area Ratio.

5.25.3.21

Area of Parking Facility. For the purposes of this Section 5.25.3 the area of parking in a structure shall include all parking spaces, access drives, aisles and other elements of the parking facility and shall include any portion of a parking facility located at grade beneath a building but not otherwise enclosed.

5.25.3.22

Definition of Underground. For the purposes of this Section 5.25.3 only, "underground " shall mean either of the following:

(1)

The location of the entire parking facility below the finished grade of the ground abutting the structure, or the underground portion thereof, which grade is maintained naturally without any structural support. No more than two access drives, which in combination total no more than 30 feet in width, shall be permitted to be above the finished grade and still be considered to be located underground.

(2)

The location of a portion of the facility above finished grade to the following extent: (1) the mean height of that portion of the parking facility above finished grade around the entire perimeter of the facility does not exceed four (4) feet, which grade is maintained naturally without any structural support (in no case, however, shall the height above mean grade for that portion of the facility facing a public street exceed four feet), and (2) the roof or top of the facility shall be either set beneath other, non-parking facility portions of the structure, landscaped or otherwise finished to serve as a pedestrian plaza, open space amenity, recreation area or pedestrian circulation. The height above mean grade shall be measured to the roof of the facility, or to the ceiling should the facility be set entirely below other non-parking elements of a building.

5.25.3.3

Exemption for Existing Parking Facilities. Structured parking facilities in existence on or before September 15, 2000, or constructed and occupied at a later date pursuant to a building or special permit in conformance with all provisions of Chapter 40A issued prior to the effective date of the provisions of this Section 5.25, shall not be subject to the requirements as to Floor Area Ratio.

5.25.3.4

Exceptions to the Provisions of this Section 5.25.3

5.25.3.41

Exemption for Residential Parking Spaces. Notwithstanding the provisions of Section 5.25.3.2 above, the following structured parking located above ground, accessory to a residential use, shall not be calculated as part of the Gross Floor Area on the lot:

(1)

One parking space located within a townhouse unit or a one, two or three family dwelling.

(2)

A freestanding parking structure containing no more than one parking space per dwelling unit up to a maximum of three parking spaces on a lot containing a one, two or three family dwelling.

(3)

One parking space per dwelling unit, up to a maximum of fifteen (15) spaces, for multifamily dwellings.

5.25.3.42

Where an above ground parking facility in a structure is proposed to be constructed (a) in the 100-year floodplain, identified as the Zone A flood hazard area (See Section 20.70), or as determined by credible evidence and calculations from a registered professional engineer or (b) on a contaminated site that is listed by the Massachusetts Department of Environmental Protection under the Massachusetts Contingency Plan (310 CMR 40.00) with a Release Tracking Number and has been tier classified, the Planning Board may grant a special permit to waive the limitations of this Section 5.25.3 so that the parking facility is not subject to the requirements in this Ordinance as to Floor Area Ratio provided only the minimum number of parking spaces required for the uses on the site are provided. In granting such a special permit, the Planning Board shall find the following:

(1)

Where in a flood hazard area, the construction of a parking facility underground is (a) not technically feasible due to the requirements of the Massachusetts Wetlands Protection Act (M.G.L. ch. 131, s.40), (b) would require construction that would violate requirements or limitations of the Massachusetts Wetlands Protection Act, (c) would, in the view of the Cambridge Conservation Commission, seriously compromise the wetlands protection objectives of the Massachusetts Wetlands Protection Act, and (d) would result in costs of construction that are significantly greater than would otherwise be typical for the location were it not in a flood hazard area; or

(2)

Where the site is contaminated, the construction of a parking facility underground (a) would, in the opinion of a Licensed Site Professional, pose significant risks to public health or the environment through disturbance of hazardous materials and could not be reasonably mitigated in accordance with state and federal regulations, (b) require construction that is prohibited by state or federal regulations related to hazardous wastes, and (c) would result in costs of construction that would render the project financially unfeasible; and

(3)

The above ground facility is designed so as to reduce its actual or perceived bulk through, among other possible techniques, limiting the number of parking spaces it contains, placement of portions of the facility below grade where feasible, or its location relative to actively occupied portions of the construction. Construction above grade is discouraged that would increase the amount of impervious area on the lot.

5.25.4

Application of FAR Limits to Residential and Non-residential Uses. This Section explains how FAR limits in the Table of District Dimensional Regulations in Section 5.30 apply.

(a)

GFA in buildings or portions of buildings used as Residences, listed in Section 4.31 a-j of this Zoning Ordinance, or Religious Purposes uses, listed in Section 4.33 a, shall not be subject to FAR limitations except where explicitly set forth in the standards for a particular district or overlay district, including but not limited to special districts or PUD districts. GFA in buildings or portions of buildings used as Residences shall be subject to other requirements as set forth in this Zoning Ordinance, including but not limited to Inclusionary Housing Requirements in Section 11.203.

(b)

Buildings or portions of buildings used for any uses other than those listed in Section 4.31 a-j or Section 4.33 a of this Zoning Ordinance shall be considered non-residential and subject to the non-residential FAR limitations of the zoning district.

(c)

On a mixed-use lot containing both uses not subject to FAR limitations (as described in Paragraph (a) above) and uses subject to FAR limitations (as described in Paragraph (b) above), the district FAR limitation shall only apply to the GFA occupied by uses subject to FAR limitations unless otherwise stated in the development controls for that district. In such cases, the GFA occupied by uses subject to FAR limitations shall be divided by the total area of the lot to determine compliance with non-residential FAR limitations.

5.25.5

Calculation for lot in two or more zoning districts.

To the extent that FAR or GFA limitations are applicable to a particular use, the maximum gross floor area permitted for that use on a lot located in two or more zoning districts shall be the sum of the total gross floor area permitted for that use in each portion of the lot, typically determined by multiplying the lot area in each district by the maximum allowed FAR for that use in that district and adding the results for each portion of the lot.

Maximum Gross Floor Area = (Lot area in district 1 x district 1 FAR applicable to that use) +
(Lot area in district 2 x district 2 FAR applicable to that use)

5.26

[Deleted]

5.27

[Renumbered 5.25.5]

5.28

Special Dimensional Standards Applicable to Dwellings.

5.28.1

[Deleted]

5.28.2

Conversion of Non Residential Structures to Residential Use.

Where it is proposed to convert an existing principal use structure, designed and built for non residential use, to residential use (excluding Transient Accommodations listed in Section 4.31.1 and Trailer Park or Mobile Home Park listed in Section 4.31 (j)), the dimensional standards generally applicable in the district as set forth in the Tables of Dimensional Requirements in Section 5.30 and other applicable regulations in this Ordinance, including permitted uses, Section 4.30 - Table of Use Regulations, shall apply except where modifications are permitted, either as-of-right or after issuance of a special permit by the Planning Board, as set forth below. The provisions in this Section 5.28.2 shall apply in all zoning districts with the exception of districts with an Open Space designation.

Intent of this Section:

(a)

To allow the economic reuse of buildings that may be substantially out of compliance with the dimensional requirements of the zoning district within which they are located, especially as they are converted to residential use.

(b)

To encourage the preservation of buildings of historic or cultural significance by providing opportunities for reuse of the structures.

(c)

To establish a framework of development standards and criteria within which existing non-residential buildings that are out of scale and character with surrounding residential uses can be converted to housing of an appropriate style and density while limiting potential negative impacts on neighbors.

5.28.20

Allowed Uses.

The Planning Board may by special permit authorize uses not otherwise allowed in the base zoning district, subject to the following conditions and limitations:

(a)

The permitted uses shall be limited to the following:

(1)

All residential uses listed in Section 4.31 (a-h), but specifically excluding Transient Accommodations listed in Section 4.31.1 and Trailer Park or Mobile Home Park listed in Section 4.31 (j).

(2)

The following institutional uses: Religious uses (4.33.a); Public or non-profit educational uses (4.33.b.1); Private preschool, day care, kindergarten (4.33.b2); Local government or other government facility (4.33.f, 4.33.g); Private museum, library, non-commercial gallery (4.33.h.2).

(3)

The following office uses: Office of an accountant, attorney, or other non-medical professional (4.34.b); Real estate, insurance or other agency office (4.34.c); General office use (4.34.d).

(4)

Any uses allowed as accessory uses to the permitted principal uses.

(b)

All permitted non-residential uses shall be limited to the ground floor or basement of the building. The Planning Board may permit non-residential uses to occupy other floors of the building only after determining that the location and design of such spaces, including access and egress, will not impact the privacy or security of residential occupants. However, the total floor area occupied by non-residential uses shall not exceed the floor area of the ground floor and basement.

(c)

The Planning Board shall determine that any proposed non-residential uses are generally compatible with residential uses in the area, including the dwelling units located within the same building, and will not cause harm or nuisance to surrounding uses.

(d)

The Planning Board shall determine that by permitting non-residential uses, there will be a compensating reduction in the number of dwelling units that would otherwise be permitted, and that the proposed non-residential uses will balance the potential adverse impacts of additional residential units, such as demand for nighttime parking.

5.28.21

GFA and FAR.

Permitted residential and religious uses shall not be limited by GFA or FAR. Other permitted uses shall be subject to the FAR or GFA limitations applicable to non-residential uses in the zoning district.

5.28.22

Dwelling Units.

There shall be no limit on the number of dwelling units permitted.

5.28.23

Yard Requirements.

The required yards shall be those of the structure existing at the time of the conversion to residential use. However, any construction occurring outside the limits of the existing structure shall be subject to the yard requirements of the district in which the structure is located.

5.28.24

Maximum Stories Above Grade and Building Height.

(a)

The maximum Stories Above Grade and maximum building height, respectively, shall be those permitted for residential uses in the district in which the structure is located, or the pre-existing conditions of the non-residential building, whichever are greater.

(b)

Any construction that occurs outside the existing limits of the structure, other than construction exempt from the height limit as set forth in Section 5.23, shall be subject to the applicable maximum Stories Above Grade and building height limit of the district in which the structure is located.

(c)

In granting a special permit, the Planning Board may approve the construction of additional Stories Above Grade beyond those permitted in Paragraph (a) if they are contained entirely within the existing structure and the Planning Board finds that the additional Stories provide space suitable for dwellings, in addition to meeting other applicable special permit criteria.

5.28.25

Open Space Requirements.

The open space requirement shall be that required in the district in which the structure is located, except as modified herein.

The dimensional and locational limitations for Private open space set forth in Section 5.22 shall not apply; any combination of at-grade private open space and decks and balconies at other levels shall be permitted as shall walks intended for non vehicular use. However, in every case where those requirements of Section 5.22 waived by this Paragraph (a) are not met, all portions of the surface of the lot shall be Green Area as defined in Article 2.000 that are (1) not covered by the building or (2) devoted to the minimum area necessary to provide at grade, conforming parking spaces and the minimum necessary circulation and driveways for no more than one parking space per dwelling unit. The amount of Private open space required may be reduced upon issuance of a special permit by the Planning Board should the Board find that full compliance cannot reasonably be expected given the existing development of the lot and the provision of parking necessary to serve the dwelling units. However, where open space requirements are not met, the Applicant shall explore the use of portions of the interior of the building to provide recreational opportunities not possible on the exterior.

5.28.26

Conforming Additions.

Conforming additions to such non-residential structures shall be permitted without reference to the limitations set forth in Section 8.22 for such additions to non-conforming structures.

5.28.27

Required Parking.

Off-street parking shall be provided as required in the Schedule of Parking and Loading Requirements, Section 6.36.

5.28.28

Criteria for Approval of a Special Permit.

In granting any special permit, the Planning Board shall consider the standards and criteria set forth in Sections 10.43 and the Urban Design Objectives set forth in Section 19.30 of this Ordinance in addition to the following review standards.

5.28.28.1

Criteria Applicable to All Projects.

(a)

Privacy Considerations. Where significant variations from the normally required dimensional standards for the district are proposed, the Board shall evaluate the impact on residential neighbors of the new housing use and any other proposed use as it may affect privacy. The location and size of windows, screening elements, decks, entries, security and other lighting, and other aspects of the design, including the distribution of functions within the building, shall be reviewed in order to assure the maintenance of reasonable levels of privacy for abutters. In reviewing a proposed development plan, the Board shall consider, among other factors, the potential negative impacts of the new activity on abutters as a result of the location, orientation, and use of the structure(s) and its yards as proposed.

(b)

Reduction in Open Space. Where it is proposed to reduce the amount of on-site Open Space below that required in the applicable district, the Board shall evaluate the proposal in light of the following:

(1)

The extent to which screening and buffering from neighbors will be accomplished

(2)

The quality and viability of the proposed open spaces as they are designed

(3)

The tradeoff in benefits and negative impacts of the loss of green space in order to provide the required amount of parking, including consideration of the feasibility of alternate parking arrangements that might produce additional green area, such as placing some or all parking within the structure

(4)

The availability of common recreational spaces within the building to compensate for the loss of usable outdoor open space

(c)

Community Outreach. The Planning Board shall consider what reasonable efforts have been made to address concerns raised by abutters and neighbors to the project site. An applicant seeking a special permit under this Section 5.28.2 shall solicit input from affected neighbors before submitting a special permit application. The application shall include a report on all outreach conducted and meetings held, shall describe the issues raised by community members, and shall describe how the proposal responds to those issues.

5.28.28.2

Additional Criteria Applicable to Larger Projects.

Where the proposed project includes more than 10,000 Gross Square Feet or more than ten (10) dwelling units, and the proposed Stories Above Grade are increased above the maximum allowed under base zoning regulations, the Board shall evaluate the proposal in light of the following:

(a)

The implications of the size or number of additional dwelling units on the anticipated demand for parking. In order to assist the Planning Board in evaluating parking impacts, an applicant for a special permit shall be required to submit a Parking Analysis, as set forth in Section 6.35.3 of the Zoning Ordinance, as part of the special permit application.

(b)

The appropriateness of the proposed layout of floor space within the building for a multifamily residential use, with attention to the typical range of unit sizes and types that would be expected for housing in the neighborhood. Considerations may include the suitability of proposed unit configurations for a variety of households, the extent to which unusual unit sizes or shapes may impact parking or overall quality of life for residents or neighbors, and the availability of customary amenities for residents such as storage, utilities, common rooms and recreational facilities.

(c)

The potential mitigating effects of the proposed occupancy of dwelling units. For instance, units designed for elderly residents or live/work spaces for professionals or artists may provide desirable housing options for Cambridge residents with fewer adverse impacts on parking or neighborhood character.

(Ord. No. 1413, 12-9-2019; Ord. No. 2022-9, 2-27-2023; Ord. No. 2024-2, 6-24-2024; Ord. No. 2025-1, 2-10-2025; Ord. No. 2025-2, 2-10-2025; Ord. No. 2025-9, 6-2-2025; Ord. No. 2025-12, 8-4-2025)

5.30.1

Dimensional regulations shall apply as set forth in the table below for the indicated zoning districts. Refer to the applicable subsections of Section 5.20 for additional detail about how the below standards are applied.

Table 5-1: Table of District Dimensional Requirements

(Ord. No. 1407, 4-29-2019; Ord. No. 2022-21, § 2, 4-3-2023; Ord. No. 2024-2, 6-24-2024; Ord. No. 2025-1, 2-10-2025; Ord. No. 2025-12, 8-4-2025)

(1)

At least fifty percent (50%) of the required Open Space in a Residence C-1 district shall meet all of the requirements of Section 5.22.1. In the case of a permitted non-residential use, the standards set forth in Section 5.22.1 shall be met for at least fifty percent (50%) of the required Open Space regardless of whether it meets the definition of Private Open Space. At least fifty percent (50%) of the required Open Space shall meet the definition of Permeable Open Space and shall not be subject to the dimensional limitations of Section 5.22.1 as applied to Private Open Space.

(2)

The height of buildings or portions of buildings used as Residences or Religious Purposes Uses may exceed the base height limit, up to a maximum of 6 stories above grade and 74 feet above grade, if all of the following criteria are met:

(a)

The building or portions of the building used as Residences complies with the Inclusionary Housing Requirements in Section 11.203 of this Zoning Ordinance, regardless of whether it exceeds the size threshold requiring compliance; and

(b)

The area of the lot on which the building is located is not less than 5,000 square feet.

(3)

A dwelling need not be set back from the street line, or building line where such may have been established on the lot, more than the average of the setbacks of the buildings, other than accessory buildings, on the lots adjacent thereto on either side.

(4)

The required side or rear yard setback may be reduced in either of the ways described below:

(a)

No side or rear yard setback shall be required for a building or portion thereof that directly abuts a building or portion thereof on an adjacent lot, as in the case of semi-detached dwellings or other adjoining buildings that share a party wall. However, portions of the building that do not directly abut portions of the building on an adjacent lot shall conform to the required side or rear yard setback.

(b)

The required setback for one side yard of a lot may be reduced if the setbacks for two opposite side yards of the lot sum to at least 10 feet, and if no portion of a building is closer than 10 feet to the exterior wall of an existing building on an abutting lot.

(c)

In the case of an alteration or addition to a building in existence since on or before January 1, 2025, the required side and rear yard setback distances shall be those of the existing building or structure. Additions or alterations that extend horizontally beyond the vertical walls of the existing building shall conform to the requirements in Table 5-1, as modified by paragraphs (a) and (b) above.

(5)

Measured from the centerline of the street, but in no case may a non-residential building be nearer the street than ten (10) feet.

(6)

Measured from the centerline of the street, but in no case may a non-residential building be nearer the street line than five (5) feet

(7)

In no case may a non-residential building be nearer the rear lot line than twenty (20) feet in Residence C-2, C-2B, C-2A, C-3, C-3A, C-3B districts. In Residence C-1 districts, no non-residential building may be nearer the rear lot line than twenty (20) feet plus one additional foot of rear yard for each four feet that the depth of the lot exceeds 100 feet, up to a maximum of thirty (30) feet. For purposes of this Footnote, the lot depth shall be that distance measured along a line perpendicular to the front lot line and extending to that point on the rear lot line most distant from the front lot line.

(8)

For buildings containing principal uses specified in Section 4.34:

(a)

The FAR shall not exceed 1.25.

(b)

The minimum front yards may be reduced to no less than five (5) feet measured from the street line.

(c)

The minimum side yards may be reduced to no less than five (5) feet measured from the street line.

(9)

In no case may a non-residential building on any lot which abuts or is separated only by a public or private way from a Residence C-1, C-2, or C-2B district be nearer the street line or side line of the lot than the minimum front and side yard requirements for a non-residential building in the residential district which said lot abuts or from which it is separated by a way. However, such increased setback requirements shall only apply to any part of a building which is located within one hundred and twenty five (125) feet of a Residence C-1, C-2, or C-2B district.

(10)

The minimum ratio of open space to lot area required for a lot which abuts/or is separated only by a public or private way from a Residence C-1, C-2 or C-2B district shall be equal to the amount of open space required in the residential district which said lot abuts or from which it is separated by a way.

(11)

Yard Requirements for non-residential buildings in the Residence C-2B District

(a)

Setbacks—In the Residence C-2B District, non-residential buildings shall comply with these yard requirements by being set back above and below ground.

(b)

Green Area—general. Two of the yards on a lot shall consist exclusively of green area as defined in section 2.000. Contrary to the provisions of said definition, hard surfaced walks and terraces shall not exceed twenty-five (25) percent of the area of each yard. At a minimum, green area setback shall consist of permanently maintained densely planted trees and shrubs that may be expected to form within three (3) years after the time of planting a continuous unbroken, year round visual screen. Every effort shall be made to retain the best existing trees in said setbacks to meet the requirements this section in whole or in part. Plans for landscaping and maintenance shall be approved by the Committee on Public Planting as appointed by the City Manager. No Certificate of Occupancy may be granted until landscaping under the terms of this section is completed.

(c)

Lots with more than four yards. If the shape of a lot creates a situation where there are more than four yards, this green area requirement shall apply to half of the yards, rounded up in the instance of an odd number of yards.

(d)

Lots in two or more zoning districts. Where a zoning district boundary line or lines split a lot, a lot partially in the Residence C-2B district shall comply with provisions elsewhere in this zoning ordinance with regard to lots in two or more zoning districts, except that the setback and green area requirements of this footnote shall apply to all parts of the lot regardless of zoning district.

(e)

Lots abutting more restrictively zoned districts. When any lot abuts a more restrictively zoned district or districts, all yards abutting the more restrictively zoned district)s) shall be designated as yards required to comply with the green area requirements of this footnote. This provision shall apply to that quantity of abutting yards numbering up to and including the maximum number of green area yards required by this footnote. The total number of green area yards required on a lot shall not be changed by the provisions of this subsection (5).

(f)

Pedestrian and vehicular access.

(i)

When a yard used to satisfy the Green Area Open Space requirement of this footnote is a front yard, the Green Area Open Space may be interrupted by not more than one path for pedestrian access to the building. Said pedestrian path shall be constructed perpendicular to the lot line and shall not be more than eight (8) feet wide. The green area yard may also be interrupted by not more than one driveway constructed perpendicular to the lot line and which is not more than twelve (12) feet wide.

(ii)

The sum of the width of the said pedestrian path and driveway may not exceed the setback provided by the smallest of the yards provided on the lot.

(iii)

The areas allowed to be used for access under this subsection (6) shall be counted as part of the twenty-five (25) percent of the total required green area which is allowed to be use for hard surfaced walks and terraces for the front yard in which the access areas are constructed.

(g)

Townhouse Development When a lot is used for townhouse development, the provisions of this footnote shall apply to the lot before subdivision into townhouse lots. Subdivision into townhouse lots shall be done in such a manner as to not affect the application of this footnote to the entire unsubdivided lot. In particular, the pedestrian path and driveways allowed.

(12)

These requirements may be reduced to a minimum required setback of ten (10) feet with the grant of a special permit from the Planning Board provided that the yard is suitably landscaped to effectively buffer the building walls from abutting lots.

(13)

For purposes of calculating FAR and for no other purpose, notwithstanding the definition of Lot in Article 2.000, a Lot in the Residence C-3B district may contain non-contiguous parcels provided that all parcels are held in identical ownership, are all located within the Residence C-3B district or any abutting Business B district, and further provided that development on any contiguous portion of the lot does not exceed an FAR of 4.0.

(14)

In a Residence C-1 District, no non-residential building plane (excluding projections as permitted by Section 5.24.2) may be nearer than seven feet, six inches (7'6") to a side lot line.

(15)

In a Residence C-1, C-2, C-2A, C-2B, C-3, or C-3A district or Business A-2 district if a non-residential building is hereafter erected on a lot adjacent to a building having a blank wall directly on the side lot line, the new building may be so designed and erected that it will be flush with that portion of the blank wall of the former building which extends along the lot line; otherwise, however, not less than the required side yard shall be provided; in any case the required side yard shall be provided for the remainder of the full lot depth. In case a side wall contains windows or in case any part of a side blank wall of an existing building shall be set back from the side lot line, then a building hereafter erected on the lot adjacent to such an existing building shall be set back from the side lot line in accordance with the provisions thereof.

(16)

In no case may a non-residential building be nearer the rear lot line than twenty (20) feet.

(17)

The cornice line of the principal front wall plane of a non-residential building facing Massachusetts Avenue shall not exceed fifty-five (55) feet in height at the front lot line. Portions of non-residential buildings in excess of this height shall be set back behind a thirty-five (35) degree bulk control plane beginning at an elevation fifty-five (55) feet above the Massachusetts Avenue front lot line. The cornice line of the principal front wall plane of a non-residential building facing Green street shall not exceed thirty (30) feet in height at the front lot line. Portions of non-residential buildings in excess of thirty (30) feet shall be set back behind a forty-five (45) degree bulk control plane beginning at an elevation thirty (30) feet above the Green Street front lot line. No non-residential building or portion of a building within forty-five (45) feet of the Green Street front lot line shall exceed forty (40) feet in height.

(18)

Open space requirements for a lot shall be determined by the mix of uses on the lot. Where one hundred (100) percent of the principal uses on a lot are residential uses listed in Subsections 4.31 a, b, d, e, and g, an area equivalent to fifteen (15) percent of the lot area shall be reserved as private open space. Where one hundred (100) percent of the principal uses on the lot are other uses, an area equivalent to fifteen (15) percent of the lot area shall be reserved as publicly beneficial open space. Where development on a lot contains both the aforesaid residential uses and other uses, an area equivalent to fifteen (15) percent of the lot area shall be devoted to both types of open space in relative proportion to the gross floor areas occupied by residential uses and other uses. The amount of each type of open space shall be determined by the formulae below. The results of said formulae notwithstanding, a minimum of fifteen (15) percent of the area of that portion of a lot within forty-five (45) feet of a front lot line facing Green Street shall be devoted to landscaped green space as specified in Subsection 4.27.3. Where more than fifty (50) percent of the area of that portion of a lot is devoted to landscaped green space, as specified in Subsections 4.27.2 and 4.27.3, none of such green space shall be counted in determining compliance with this Subsection 5.332d. Where fifty (50) percent or less of the area of that portion of a lot is devoted to landscaped green space, such area may be counted in determining compliance with this Subsection 5.33 2d.

(a)

Minimum required total area reserved for both types of open space = lot area multiplied by .15.

(b)

Share of development devoted to residential uses = gross residential floor area divided by gross floor area of entire development.

(c)

Minimum required private open space associated with residential use = total open space required multiplied by residential share.

(d)

Share of development devoted to other uses = other gross floor area divided by gross floor area of entire development.

(e)

Minimum required publicly beneficial open space = total open space requirement multiplied by other use share.

(19)

Where any lot abuts a residential district, non-residential buildings above and below ground shall be set back a minimum of twenty (20) feet from the zoning district boundary line, notwithstanding anything to the contrary provided in Article 6.000 of this Ordinance. Said setback shall consist exclusively of landscaped green area as defined in Article 2.000. Where the zoning district boundary line splits a lot the minimum twenty (20) foot setback shall be measured from the lot line(s) located in the residential district. At a minimum green area setback shall consist of permanently maintained, densely planted trees and shrubs that may be expected to form within three (3) years after time of planting a continuous, unbroken, year round visual screen. Every effort shall be made to retain the best existing trees in said setbacks to meet the requirements of this section in whole or in part. Plans for landscaping and maintenance shall be approved by the Committee on Public Planting as appointed by the City Manager. No Certificate of Occupancy may be granted until landscaping under the terms of this section is completed.

(20)

Subject to the provisions of Footnote 1 in Section 4.40 - Footnotes to the Table of Use Regulations.

(21)

Thirty-five (35) feet [or maximum non-residential height permitted in the abutting residential district, but in no case higher than fifty-five (55) feet] within fifty (50) feet of a residential district line. Where the zoning district boundary splits a lot the fifty (50) feet shall be measured from the lot lines located in the residential district. The height, however, may exceed thirty-five (35) feet provided the non-residential building is set back a minimum distance equal to two-thirds (2/3) the height.

(22)

However, for the side yard of any lot abutting another lot (where that lot does not abut Massachusetts Avenue and where all or a majority of it is located in a residence district) no non-residential building shall be set nearer than twenty feet to (1) either the residence/Business A-2 zoning district line where the lot line is located in the BA-2 District or (2) the side lot line itself where that lot line is located in the residence district. Nevertheless, the provisions of footnote (15) shall continue to apply.

(23)

Or two-thirds (2/3) of the height of the rear wall whichever is greater; however in the Business C district no rear yard shall be required where the rear lot line abuts a lot all of which lies in a business or industrial district.

(24)

Provided however that any portion of a non-residential building having a height greater than thirty-five (35) feet shall be set back of a bulk control plane rising at an angle of forty-five (45) degree from the plane of the principal front wall and rear wall planes beginning at a height of thirty-five (35) feet.

Where the parcel has frontage on two or more streets, this setback plane provision shall apply only to the front wall plane facing the principal abutting arterial street and to the opposite wall plane facing either a side or front property line.

In addition to the above provisions, that portion of a non-residential building located within fifty (50) feet of a residential zoning district line shall be limited to thirty-five (35) feet where the maximum non-residential height permitted in the residential district is thirty-five (35) feet or less.

(25)

Or the setback of the principal front wall plane of any adjacent building facing the same street, whichever is less.

(26)

For development in which all parking is provided entirely below grade, the following dimensional modifications shall be allowed:

(a)

FAR may be increased to 2.0

(b)

Front, Side and Rear yard requirements for non-residential buildings shall be modified to a minimum of ten (10) feet. Sites with two front yards that have a radiused front yard where two streets intersect may be considered as if the adjoining property lines are projected to intersect. Projecting bays and roof decks which are located on portions of a non-residential building below thirty-five (35) feet in height shall be eligible for the setback exception allow in Section 5.24.2 even if the structure itself if greater than 35 feet in height.

(27)

The following dimensional modifications shall apply in the Business A-5 district:

(a)

For any portion of a building within fifty feet (50') of a residential district, the height of that portion of the building shall not exceed thirty-five feet (35').

(b)

The Planning Board may grant a special permit to exclude Retail or Consumer Service Establishments, as listed in Section 4.35 of the Zoning Ordinance, from the calculation of Gross Floor Area (GFA) and Floor Area Ratio (FAR) on the lot if they are located on the Ground Story. The conditions of the special permit shall clearly describe what areas are excluded and what range of uses shall be permitted, along with other conditions to ensure that the objectives of the area are met.

(c)

Notwithstanding any other section of this Zoning Ordinance, roof decks on any Story of a building shall be exempt from gross floor area calculations provided the roof deck is not within 20' of a residential district.

(28)

The required front yard for a dwelling constructed entirely above a commercial establishment shall be reduced to the existing or permitted front yard of the commercial establishment in any Business district except the Business A-3 district.

(29)

A side yard setback of H+L/7 and a rear yard setback of H+L/5 shall be required only for nonresidential uses abutting residences, residential or open space districts or public parks and recreation areas. These requirements may be reduced to a minimum required setback of ten (10) feet on special permit, provided that the yard is suitably landscaped to effectively buffer building walls from abutting lots.

(30)

One hundred and thirty (130) feet by special permit for buildings related to storage and processing of materials permitted in Section 4.37m.

(31)

Except that within the area bounded by Binney Street on the north, a line one hundred and fifty (150) feet easterly of Cardinal Medeioros Avenue on the west, Broadway on the south, and the railroad right of way on the east, the FAR may be increased to 3.2 for non-residential uses for an addition to a building in existence as of June 1, 2001 provided that for each four hundred and fifty (450) square feet of GFA added above an FAR of 2.75 one existing parking space is permanently eliminated.

(32)

In the Industry B District, a hotel use (Section 4.31.1.b) shall have a Maximum FAR of 4.0.

(33)

In an Office, Business or Industrial district no non-residential building shall be erected nearer to the street line than is permitted in the adjacent Residence district within a distance of fifty (50) feet from the Residence district boundary line, except where such building is separated by a street from the Residence district.

(34)

In Office, Business or Industrial districts no non-residential building shall be erected within ten (10) feet of the side lot line of any abutting lot, all or the major portion of which is in a Residence district.

(35)

In a Business C district, within fifty (50) feet of a residential zone, no non-residential building shall be erected that is greater than thirty-five (35) feet in height.

(36)

The maximum building height and FAR for Dormitory (but excluding resident fraternity or sorority) Uses, Section 4.33 b(7), shall be modified for certain districts as set forth in the table below. Where a lot contains a combination of dormitory and other non-residential uses, then the total FAR on the lot shall not exceed the maximum set forth in the table below, and the FAR for all non-residential uses other than Dormitory (determined by dividing the GFA occupied by all non-residential uses other than Dormitory by the total lot area) shall not exceed the maximum non-residential FAR otherwise applicable in the district.

(37)

In a Residence C-1 district, an applicant for a building permit for a building that exceeds three stories above grade and 35 feet above grade, if it does not require a Planning Board Advisory Consultation per Section 19.40 of this Zoning Ordinance and does not require any special permit from the Planning Board, shall:

(i)

schedule a meeting to show plans or renderings of the proposed building, answer questions and gather feedback from abutters;

(ii)

prepare a notification flyer including, at a minimum, a general description of the project, the date, time, location, and other information necessary for people to attend the meeting, and contact information (telephone and e-mail, at minimum) for the developer;

(iii)

provide that notification by mail to abutters, owners of land directly opposite on any public or private street or way, and abutters to the abutters within three hundred feet of the property line of the lot as they appear on the most recent applicable tax list, to the Community Development Department electronically for posting on the City of Cambridge website, and to others whom the applicant may choose to contact;

(iv)

erect and maintain for a minimum of 20 days, beginning at least 10 days before the date of the meeting, a notification sign on the site of the proposed building containing the information in subparagraph (ii) above and meeting the Location and Number and Graphic and Construction Standards in Section 10.42.1, Paragraphs (a) and (d) of this Zoning Ordinance; and

(v)

include with the building permit application a copy of the notification and mailing list, a photograph and site plan showing the location of the notification sign(s), a summary of the meeting, who attended, and what questions and feedback were received.

(Ord. No. 2025-1, 2-10-2025; Ord. No. 2025-12, 8-4-2025)

Editor's note— Ord. No. 2025-1, adopted Feb. 10, 2025, repealed the former 5.40, and enacted a new 5.40 as set out herein. The former 5.40 pertained to transitional requirements and derived from the original Zoning Ordinance.

5.51

[Deleted]

5.52

[Deleted]

5.53

[Deleted]

5.54

Special Regulations for Municipal Elementary and Middle ("K-8") Schools. The following regulations shall apply to the reconstruction, alteration or expansion of existing municipal K-8 school uses. The regulations of this Section shall apply where development is proposed on lots where the existing and proposed principal use is a municipal K-8 school; however, such lots may include other uses customarily associated with a municipal K-8 school such as public recreation, public open space, community center, pre-school and after school programs or municipal library. Where a regulation in this Section 5.54 contradicts any regulation set forth elsewhere in the Zoning Ordinance, including the requirements of Article 8.000, the regulations of this Section 5.54 shall apply.

5.54.1

The following modifications to the dimensional, parking and other requirements applicable in the zoning district as set forth in Paragraphs (a-f) below shall be permitted upon issuance of a Building Permit by the Commissioner of Inspectional Services, subject to the limitation set forth in Paragraph (g) below:

(a)

The maximum permitted Floor Area Ratio shall be the existing Floor Area Ratio for all buildings on the lot at the time of application for a Building Permit, or the maximum Floor Area Ratio allowed under the applicable zoning district regulations, whichever is greater.

(b)

Areas located atop the roof of a building that are used as a playground or outdoor educational space for school-related activities shall not be included in the calculation of Gross Floor Area or Floor Area Ratio on the lot, provided that the space is substantially open to the sky (structures covered with web or netting shall not be considered enclosures).

(c)

For any new structures, additions to an existing structure, or portions of a structure that are demolished and reconstructed in a residential zoning district, the minimum yard requirements otherwise applicable in the district shall not apply, provided that no new structure may be nearer than ten (10) feet to any public street or nearer than fifteen (15) feet to any other abutting lot line; however, for portions of a lot located within an Open Space zoning district, the minimum yard requirements in the base zoning district shall apply. For existing portions of a structure which are neither demolished nor expanded, the required yards shall be those of the structure existing at the time of application for a Building Permit.

(d)

For any new structures, additions to a structure, or portions of a structure that are demolished and reconstructed in a residential zoning district, the maximum building height shall be forty-five (45) feet, or the maximum height allowed under zoning district regulations, whichever is greater; however, for portions of a lot located within an Open Space zoning district, the maximum height in the base zoning district shall apply. For existing portions of a structure which are neither demolished nor expanded, the height of the existing structure shall be permitted.

(e)

The minimum required number of off-street motor vehicle parking spaces shall be the number of legally existing off-street parking spaces on the lot or the minimum number of off-street parking spaces required by Article 6.000, whichever is fewer. Where existing parking spaces are proposed to be reconstructed or relocated, those spaces shall conform to the location, design and layout requirements of Article 6.000.

(f)

The minimum required number of off-street loading bays shall be the number of legally existing off-street loading bays on the lot or the minimum number of off-street loading bays required by Article 6.000, whichever is fewer. Where loading bays are proposed to be reconstructed or relocated, those loading bays shall conform to the location, design and layout requirements of Article 6.000.

(g)

The provisions set forth in Paragraphs (a-f) above shall apply only if there is no net reduction in the area of Public Recreational Open Space on the lot. For the purposes of this Section 5.54, Public Recreational Open Space shall be defined as any contiguous outdoor space having both a width and length of at least twenty-five (25) feet that is available for customary recreational use by the general public and that meets the definition of Public Open Space as set forth in Article 2.000 of this Zoning Ordinance. Notwithstanding anything to the contrary in the definition of Public Open Space, areas beneath unenclosed structures that are accessory to outdoor public recreational uses, such as play structures, shading devices or player dugouts, may be counted as Public Recreational Open Space. Public Recreational Open Space may be altered or relocated on the lot, provided that the total area of space meeting the definition herein is not decreased.

5.54.2

Where it is proposed to reconstruct, alter or expand an existing municipal K-8 school use, any dimensional, parking or other zoning requirements, including those set forth in Section 5.54.1 above, may be waived upon the granting of a special permit by the Planning Board, subject to the conditions and limitations set forth below.

(a)

The Floor Area Ratio on the lot shall not exceed the existing Floor Area Ratio on the lot, except that the Planning Board may approve an increase in Floor Area Ratio to 1.25 for any portion of the lot located within a residential zoning district (but excluding portions of the lot located within an Open Space zoning district).

(b)

For portions of a lot located within an Open Space zoning district, the minimum yard requirements in the base zoning district shall continue to apply to any new buildings or additions to buildings.

(c)

In a residential zoning district, the maximum height of any new building or addition to a building shall not exceed fifty-five (55) feet, except that the Planning Board may approve heights of up to sixty-five (65) feet for portions of a building located at least fifty (50) feet from any lot line. In an Open Space zoning district, the height of any new building or addition to a building shall not exceed the maximum height allowed in the base zoning district.

(d)

The minimum off-street parking requirement shall not be waived except upon issuance of a special permit for Reduction in Required Parking under Section 6.35.1. The Planning Board may approve a reduction in the number of required loading bays upon finding that the proposed loading bays are sufficient to serve the school use. New parking spaces and loading bays shall conform to the location, design and layout requirements of Article 6.000.

(e)

The net area of Public Recreational Open Space on the lot, as defined in Subsection 5.54.1, Paragraph (g) above, shall not be reduced by more than ten percent (10%) of the existing area. In approving any net reduction in Public Recreational Open Space, the Planning Board shall make a determination that the proposed Public Recreational Open Space shall provide benefits to the general public that are at least commensurate with the existing Public Open Space on the lot.

(f)

In addition to the General Special Permit Criteria set forth in Section 10.43 and the Citywide Urban Design Guidelines set forth in Section 19.30, the Planning Board shall make a determination that the proposed changes to the lot have been designed to minimize or mitigate adverse impacts on neighboring residential properties. In making this finding, the Planning Board shall consider the following:

(i)

Arrangement of building height and bulk within the lot.

(ii)

Access and egress for pedestrians, bicycles and motor vehicles, including pick-up and drop-off areas for buses and cars.

(iii)

Location and screening of functions such as parking, loading, trash handling and mechanical equipment.

(iv)

Current impact of existing buildings and existing patterns of use on the site.

(Ord. No. 2025-1, 2-10-2025)