BYLAW: Dimensional Regulations
MUNICIPALITY: Amherst, MA.
DATE ADOPTED: July 1998
PURPOSE OF BYLAW: Establishes dimensional regulations by zoning district for lot area, frontage, setback and yard requirements, and maximum coverage and height.
FOR MORE INFORMATION ON THIS BYLAW, CONTACT:
Jonathan Tucker, Planning Director
4 Boltwood Ave.
Amherst , MA 01002
TEXT OF THE BYLAW
SECTION 6.0 OVERVIEW
A lot may not be so reduced as to fail to satisfy any minimum dimension, area or yard required for a permitted principal use except as specified in Sections 4.3 and 4.4. Minimum lot area, frontage, setback and yard requirements, and maximum coverage and height limitations shall be prescribed in the following Table 3, "Dimensional Regulations." Explanation of the column headings can be found in Section 6.1, Interpretation. Section 6.2, Modification of Regulations, discusses the procedure which may be used to modify several of the requirements in Table 3. For non-conforming lots, see Section 9.1 For dimensional regulations in the Educational (ED) District, see Section 3.213.
SECTION 6.1 INTERPRETATION
The following explanation shall apply to the column headings in Table 3.
6.10 Basic Minimum Lot Area
Except as herein specified, no dwelling or other principal building shall be constructed or used on a lot having less than the prescribed basic minimum lot area in square feet.
6.11 Cluster Minimum Lot Area
No dwelling or other principal building in a Cluster Development shall be constructed or used on a lot having less than the prescribed cluster minimum lot area, in square feet.
6.12 Additional Lot Area Per Family
No dwelling for use by more than one family shall be constructed, converted, or occupied unless the lot contains at least the basic minimum area plus the prescribed additional area per family for each family in excess of one.
6.13 Basic Lot Frontage and Cluster Lot Frontage
Except as herein specified, no dwelling or other principal building shall be constructed or used on a lot having less frontage on a street than the prescribed minimum lot frontage, or cluster lot frontage in cluster development.
Such frontage shall be measured along the street right-of-way line on which the lot abuts, except that the frontage of lots on the convex side of a curve in a street may be taken as the straight distance between the points on the side lot lines intersected by the prescribed minimum setback line. In the case of lots which have more than one-half of their frontage along the curve of a permanent turnaround (at the end of a dead end street) or of a similar curved street segment serving no more than six (6) dwelling structures, said straight distance between the points on the side lot lines need not exceed seventy (70) percent of the prescribed minimum. On corner lots, where the included angle is less than 135 degrees, either street may be considered as the frontage street, but not both together. This requirement shall not apply to dwellings in a Planned Unit Residential Development.
In the General Business (B-G), Limited Business (B-L), Commercial (COM), and Village Center Business (B-VC) districts, frontage requirements apply to Residence Uses only (Section 3.32).
6.14 Minimum Setback
The minimum setback shall be determined by a line parallel to the street right-of-way line extending from one side lot line to the other. No part of any building, except uncovered steps, and no accessory structure (other than a sign) having a height of more than four feet shall be placed within or protrude into the area between the setback line and the street line. In the case of corner lots, the setback line shall be observed for all bordering streets.
In the General Business (B-G) District, the 20 foot minimum setback applies only to a part of a building which is within 200 feet of the side boundary of a Residence District abutting on the same street within the same block; otherwise, no setback is required.
6.15 Minimum Side Yard
The minimum side yard shall be the area between the side lot line and the side yard setback line, extending from the front yard to the rear lot line. An accessory structure may be located within the minimum side yard only if it is located behind the front building line.
An accessory structure having a height of six feet or less shall be set back a minimum of three feet from the side lot line. An accessory structure over six feet in height shall be setback a distance equal to its height.
In the General Business (B-G) and Light Industrial (LI) districts, minimum side yards shall be at least 20 feet when adjoining a residence district. Otherwise, side yards are not required, but if provided, shall be at least ten feet. In the General Residence (R-G) District, a single-story garage tool shed, gazebo or similar accessory structure may, under a Special Permit, be located within the side yard behind the frontline of the principal building if such use, location, and proposed dimensions are consistent with the prevailing pattern of existing development for such structures in the neighborhood.
For towers or other structures associated with commercial and public wireless communications uses, the provisions of Section 3.340.2 shall apply and prevail.
6.16 Minimum Rear Yard
The minimum rear yard shall be a similar unbroken area along the rear lot line, subject to the same provision regarding accessory buildings and structures as the rear portion of the required side yard.
In the General Business (B-G) and Light Industrial (LI) districts, minimum rear yards shall be at least 20 feet when adjoining a residence district. Otherwise, rear yards are not required, but if provided, shall be at least 10 feet. For towers or other structures associated with commercial and public wireless communications uses, the provisions of Section 3.340.2 shall apply and prevail.
6.17 Maximum Building Coverage
Maximum building coverage shall be computed as the percentage of the total lot area which may be covered by all principal and accessory buildings and structures. For the purposes of the subsection, a portion of a lot shall be considered as being covered by a structure if it is enclosed on at least three sides by a wall or other substantially sight-impervious fence more than six feet high (whether or not having a roof), or if it has any part of any structure above it in a vertical line. In the case of a Cluster Development as defined in Section 4.3, building coverage shall be calculated as the percentage of the total area of the development which may be covered by all principal and accessory buildings and structures.
6.18 Maximum Lot Coverage
Maximum lot coverage shall include the percentage of a lot covered in the manner described in Section 6.17, Maximum Building Coverage, plus that portion of a lot covered by driveways, parking areas, walkways, tennis courts, swimming pools or other similar surfaces.
For the purposes of this Bylaw, all such surfaces, whether constructed of impermeable materials (i.e., concrete, bitumimous asphalt, oil and stone and the like) or constructed of permeable materials (i.e., gravel, peastone and the like) shall be included in the calculation of maximum lot coverage.
6.19 Maximum Height
The maximum height of a building shall be measured from the highest point of any roof or parapet to the average finished grade on the street side of the structure, provided that in no case shall the height of any exterior face of a building exceed the permitted height by more than ten feet. Height limitations shall not apply to chimneys, spires, cupolas, TV antennae and other parts of buildings or structures not intended for human occupancy. Towers, antennae, panels, dishes and other such structures attached to a building in association with commercial and public wireless communication uses shall not exceed the maximum height of said building, as above defined, by more than ten feet. Related electronic equipment and equipment structures shall not exceed the maximum height. For towers and other such free-standing structures associated with wireless communications uses, the provisions of Section 3.340.2 shall apply and prevail.
SECTION 6.2 FENCES
6.20 Fences - Fences or walls or any similar type structure, shall be considered accessory structures and shall be permitted in the required yards subject to the conditions and requirements of Sections 6.22 through 6.29, except that fences in the B-G and B-L Districts shall require a Special Permit.
6.21 Plantings/Shrubbery - Landscape plantings shall be permitted in the required yards subject to the conditions and requirements of Sections 6.23 and 6.27.
6.22 Fences associated with agricultural uses on parcels of land of five (5) acres or larger are exempt from the regulations of Sections 6.2. Razor fences are prohibited.
6.23 All privately owned fences or walls shall be erected on private property and shall be no closer to any public sidewalk than thirty (30) inches. No landscape plantings shall intrude into or over a public sidewalk for a height of eight feet above the sidewalk.
6.24 Fences and walls shall not exceed four (4) feet in height along the front lot line and that portion of the side lot lines between the front lot line and the minimum front setback line. Fences and walls shall not exceed six (6) feet in height along that portion of side lot lines between the minimum front setback line and rear lot line, and along the rear lot line.
6.25 Fences located within the side or rear yards and exceeding six feet in height shall be set back a distance equal to their height.
6.26 All fences, including temporary construction fences, but excepting agricultural fences as defined in Section 6.22, shall require a building permit.
6.27 On corner lots, no fence, wall or landscape/plantings shall be located within the clear sight triangle so as to obstruct visibility at the intersection in a manner that will jeopardize the safety of vehicles and pedestrians. The clear sight triangle is that area formed by the intersecting street lines and a straight line joining said street lines at a point twenty-five (25) feet distant from the point of intersection of street lines.
6.28 Temporary fences on construction sites may be a maximum height of eight (8) feet to protect the site, providing the fence meets the requirements of Section 6.27. The Building Commissioner, upon the issuance of a building permit, may set a limit as to the length of time the fence may remain erected.
6.29 Fence, wall, and planting requirements as found in Sections 6.23 through 6.28 may be modified by the Zoning Board of Appeals by the issuance of a Special Permit, based upon a finding that such modification is not detrimental to the neighborhood nor that such modification will jeopardize vehicular and/or pedestrian traffic.
SECTION 6.3 FLAG LOTS
In the Office Park (OP) , General Residence (R-G), Village Center Residence (R-VC), Neighborhood Residence (R-N), Outlying Residence (R-O), and Low Density Residence (R-LD) Districts only, individual lots which do not have the required amount of street frontage may be permitted under the following conditions:
6.30 Any such lot which is included within a Definitive Subdivision Plan may be allowed by the Planning Board provided the lot meets all of the requirements of Section 6.32 through Section 6.37.
6.31 Any such lot which is not part of an Approved Definitive Subdivision Plan, may be allowed by the Zoning Board of Appeals by Special Permit provided that the lot meets all of the requirements of Section 6.32 through 6.37.
6.32 The area of each flag lot, exclusive of the access strip, shall be at least double the minimum lot area normally required for that district, except in a Cluster Subdivision, in which case it shall be at least double the minimum lot area required for a cluster lot in that district. In the FP District, the area of flag lots shall be as provided for in Sections 3.2832, 4.3271 and 4.3272.
6.33 Each lot shall have an access strip with a minimum street frontage of forty feet, a minimum width of forty feet at any point between the street and the principal building, and a maximum length of four hundred feet, after which distance the access strip shall end and the building area of the lot shall begin. Where driveway access to a principal building is achieved over the access strip of the lot, then said access strip shall have no change of direction greater than 45 degrees.
For any flag lot included within a Definitive Subdivision Plan, the Planning Board may allow an access strip in excess of 400 feet as part of its subdivision approval if it judges the proposed modification to be in conformance with the intent of Sections 6.330-6.335.
For any flag lot which is not part of a Definitive Subdivision Plan, the Zoning Board of Appeals, acting as the Special Permit Granting Authority, may allow an access strip in excess of 400 feet upon a finding that such a modification will:
6.330 Not have a substantial detrimental impact on the declared intent and purposes of any overlay district in which the land is situated.
6.331 Not create an undue safety hazard.
6.332 Not have a substantial adverse environmental impact on groundwater quality, wetlands, significant wildlife habitat, prime farmland or other environmentally sensitive resources.
6.333 Not remove, destroy or obstruct prominent natural features and views.
6.334 Not remove, destroy or irrevocably alter significant historical, archeological and/or cultural resources.
6.34 The width of that portion of the lot where the principal building is to be constructed, known as the building area, shall equal or exceed the distance normally required for street frontage in that district. Said width shall be measured along the nearest continuous streetward boundary of the building area of the lot. In a Cluster Subdivision, the width of the lot where the principal building is to be constructed shall equal or exceed the distance required for cluster lot frontage in that district.
6.35 That portion of a flag lot within which the principal building is to be located shall be considered the building area. The building area of a flag lot shall be capable of containing a circle whose diameter is equal to or greater than the minimum standard street frontage required in the district where the flag lot has its frontage, without any portion of sae falling outside of the property.
6.36 There shall be no more than three flag lots adjacent to each other at the street line.
6.37 Access to the lot shall meet the following requirements:
6.371 Unimpeded access shall be provided either across the access strip or across an easement at least twenty feet wide.
6.372 The driveway within the privately owned access strip or easement shall have adequate drainage and shall not exceed 5% grade within thirty feet of the property line at the street.
6.373 In all instances where either two, or three, flag lots have their strips adjacent to each other at the street line, access to the lots shall be provided by a single common driveway only, with a minimum width of sixteen (16) feet.
6.374 Any shared driveway shall provide access to a maximum of four lots, including flag lots and any adjacent standard lots.
6.375 All access driveways within the privately owned access strip shall be so drained as to prevent damage or hazard to abutting properties or public streets, and shall be paved with bituminous asphalt, concrete, compacted gravel or similar paving material.
6.38 There shall be no more than three (3) flag lots created from any land identified, according to the records of the Assessor's office, as a single parcel of land as of the effective date of this Section (11/9/87) unless such flag lots are proposed as part of the Definitive Subdivision.
SECTION 6.4 LOTS WITHIN THE FLOOD PRONE-CONSERVANCY DISTRICT
If any portion of a lot falls within the Flood Prone-Conservancy District, that portion may be used to meet the minimum lot area and yard requirements for the District in which the remainder of the lot is situated.
SECTION 6.5 EDUCATIONAL AND RELIGIOUS USES
All structures approved after January 1, 1994, by a permit granting authority for educational or religious uses shall have minimum front, side and rear set backs twice the distance shown in Table 3 for that zoning district, except in the B-G District where the setbacks in Table 3 shall apply.
TABLE 3 - DIMENSIONAL REGULATIONS (click here to view)
a. Requirement may be modified under a Special Permit, issued by the Zoning Board of Appeals.
b. Applies to Residence Uses only (Section 3.32).
c. Applies to any part of a building which is within 200 feet of the side boundary of a Residence District abutting on the same street within the same block; otherwise, no front setback is required.
d. A side yard need not be provided on one side of a single family dwelling if it shares a party wall or double wall with a single-family dwelling on the next lot built at the same time.
e. Rear and side yards shall be at least 20 feet when adjoining a Residence District. Otherwise, rear and side yards are not required, but if provided, shall be at least 10 feet.
f. Rear and side yards shall be at least 50 feet when adjoining a Residence District. Otherwise, rear and side yards shall be at least 10 feet.
g. See Section 6.15 for Interpretation.
h. A buildable lot shall contain either 90% of its total lot area, or 20,000 square feet, in contiguous upland acreage.
i. Substitute with dimensional requirements in Section 4.332 for 10% affordable projects within cluster subdivisions only.
j. 85% in B-L zone adjacent to B-G and along University Drive; 70% in more outlying B-L and in COM.
k. Requirements may be modified under a special permit granted for a cluster subdivision.
l. The above dimensional regulations shall apply to all educational and religious uses located in the zoning districts listed above, except as provided for in Section 6.5.
m. For new town houses (Section 3.322) and apartments (Section 3.323), these areas shall apply in addition to the areas required by this table for any existing dwelling units on the lot. In addition, the density for new town houses and apartments shall not exceed one dwelling unit per 6,000 sq. ft. of the remaining lot area, or the entire area in the case where there are no existing dwelling units.