Rochester City Zoning Code
ARTICLE 19
Dimensional Regulations
§ 275-19.1 Overview.
A.
Dimensional requirements by zoning district are provided in the following tables which are located at the end of this chapter:[1]
(1)
Table 19-A, Dimensional Standards - Residential Districts.
(2)
Table 19-B, Dimensional Standards - Commercial Districts.
(3)
Table 19-C, Dimensional Standards - Industrial Districts.
(4)
Table 19-D, Dimensional Standards - Special Districts.
[1]
Editor's Note: The tables are included as attachments to this chapter.
B.
Additional dimensional standards are provided throughout this chapter.
§ 275-19.2 Dimensional provisions.
General dimensional regulations and regulations (as well as clarifications, notes, and references) specifically referenced to the tables follow:
A.
Building height.
(1)
Adjacent to residences. In any zone, required setbacks shall be increased by one foot for each foot buildings exceed 35 feet in height.
(2)
Barns. In the AG District barns may exceed the height limit.
(3)
Exceptions. Unless subject to FAA requirements, the height limits specified in the tables shall not apply to the following: chimneys, flares, stacks, storage silos, satellite dishes, antennas, elevator shafts, rooftop mechanical equipment, ventilators, skylights, church towers, cupolas, domes, pinnacles, spires, silos, water tanks, and similar elements, provided the combination of the building and element does not exceed 100 feet in height (unless otherwise specifically provided for in this chapter).
B.
Building separation. Except within the DC Zone, all buildings or open covered structures situated on the same lot must be separated from one another by a minimum of 10 feet or as regulated by the New Hampshire State Building or Fire Code.
C.
Building stories.
(1)
Floors below grade. Floors with any portion below grade do not count toward meeting requirements for a minimum number of stories. Any floor with at least 1/3 of the floor to ceiling space situated at or above grade shall count toward the maximum number of stories permitted.
(2)
Upper floors. Upper story/attic spaces count toward the minimum required number of stories specified in the dimensional tables if a portion of the floor area of those upper story/attic spaces equal to at least 1/2 the floor plate of the building has a ceiling height of at least seven feet.
D.
Corner lots. On corner lots, for the purpose of setbacks, there shall be established a front, a street-side side, a (regular) side, and a rear. The ordinary front setback shall apply to that section of the lot which is deemed the front, as determined by the Director of Building, Zoning, and Licensing Services (based upon the locations of the front entrance, street address, path to the front, and driveway; E911 standards; the prevailing pattern of the other buildings on both blocks; impact upon the streetscapes; and other appropriate factors). The street-side setback shall apply to that side of the lot facing the other street. The street-side setback shall be the ordinary side setback in that district.
E.
Density rings. The density rings are shown on the Official City of Rochester Zoning Map that is adopted as part of this chapter and only apply to multifamily dwellings/developments. The rings are defined as follows:
[Amended 2-6-2018; 5-7-2019]
(1)
There is no minimum lot area per dwelling unit applicable within the Downtown Commercial (DC) Zone District. For areas outside of the DC Zone District, the minimum lot area per dwelling unit within a one-mile radius of the center of Rochester shall be 5,000 square feet. The minimum lot are per dwelling unit outside of the one-mile radius of the center of Rochester shall be 7,500 square feet.
(2)
The minimum lot area per dwelling unit within a one-half-mile radius of the center of Gonic and East Rochester shall be 5,000 square feet. The minimum lot are per dwelling unit outside of the one-half-mile radius of the center of Gonic and East Rochester, shall be 7,500 square feet.
(3)
Any lot that is partially within the radius of a density ring shall be treated as if it were entirely within the radius of the density ring.
F.
Double frontage lots. On double frontage lots, for the purpose of setbacks, there shall be established a front, two sides, and a rear. The ordinary front setback shall apply to that section of the lot which is deemed the front, as determined by the Director of Building, Zoning, and Licensing Services (based upon the locations of the front entrance, street address, path to the front, and driveway; E911 standards; the prevailing pattern of the other buildings on both blocks; impact upon the streetscapes; and other appropriate factors). The regular rear setback shall apply to that section of the lot opposite the front.
G.
Exempt structures. Nonhabitable utilities and utility-type structures erected by a governmental, public utility or nonprofit agency which customarily are built within the road right-of-way, on undersized lots, or close to property lines, and which cannot reasonably be made to conform to the requirements of the dimensional tables, are exempt from those requirements.
H.
Frontage and access. Access to lots shall be taken from the same road where the lot frontage is located unless waived by conditional use.
I.
Frontage.
[Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II)]
(1)
Continuous. An area used to meet frontage requirements must be continuous and unbroken. Two or more discrete areas may not be added together to meet frontage requirements.
(2)
Culs-de-sac. The Planning Board may reduce the required frontage on the curved end portion of a cul-de-sac by up to 20% by conditional use (due to the narrower frontage relative to lot width that naturally occurs along a cul-de-sac).
(3)
Depth. The front portion of every lot must be at least the width of the required frontage from the front property line extending back at least the depth of the setback from the front property line.
J.
Lot area; usable area. No lot shall be approved unless a rectangle measuring at least 3,000 square feet can be fit inside the lot beyond any required setbacks, wetlands, wetland buffers, or slopes greater than 25%. The rectangle must be located in an accessible part of the lot and its width must measure at least 30 feet.
K.
Lot coverage. All of the following elements are considered part of lot coverage: buildings, roofed structures, or impervious surfaces.
L.
Multiple principal uses. Where there are multiple principal uses on one lot or parcel, minimum required lot sizes are not aggregated except where there are multiple residential uses; i.e., it is necessary only that the lot size meet the minimum requirement for any use proposed for the lot. (Example: A certain zoning district stipulates a minimum lot size of 40,000 square feet for all permitted uses, including single-family and commercial both of which are allowed. To accommodate a single-family house and a commercial use on the same lot, a lot 40,000 square feet would be required, rather than a lot 80,000 square feet. However, to establish duplexes, townhouses, and apartments on the same lot, the minimum lot size would be based on the total number of dwelling units.) Nonetheless, as part of site plan review, the Planning Board may stipulate appropriate conditions to ensure compatibility of the multiple uses.
M.
Nonconformities, creation of. Except for open space lots and conservation land, lots and sites may not be created or modified in any manner that would make them nonconforming in terms of any dimensional requirements of this chapter.
N.
Open space lots; frontage. It is not necessary for open space lots and conservation land to be in compliance with any requirements of the dimensional tables. Minimum frontage of 12 feet is required in order to ensure access.
O.
Right-of-way encroachments. Within commercial districts where there is no minimum front setback, encroachments may occur within the public right-of-way as follows:
(1)
Footings below grade may encroach as needed subject to approval of the Director of Building, Zoning, and Licensing Services and Public Works Department.
(2)
Awnings over the sidewalk provided there is a vertical clearance of at least seven feet.
(3)
Architectural elements, such as balconies, bay windows, and cornices, on upper floors provided the encroachment does not exceed two feet and provided there is a vertical clearance of at least 10 feet.
P.
Rounding off. In any calculation, where the final number results in a fraction of a unit, the number of units shall be rounded up to the next whole number where the fraction is 1/2 or greater. It shall be rounded down to the next whole number where the fraction is less than 1/2.
Q.
Setbacks for accessory uses. Setback requirements apply to buildings and roofed structures accommodating accessory uses in similar fashion as those accommodating principal uses except where otherwise specified.
R.
Setback application.
(1)
Required setbacks apply to buildings, roofed structures, open air decks, porches, ground-mounted mechanical equipment, ground-mounted satellite dishes, fuel tanks, and bulkheads. The setback requirement applies whether the element is a principal or an accessory use. [See extensions beyond setbacks (i.e., into setback areas) below; special exception provisions for porches; and several other specific exceptions and special provisions regarding setbacks in this chapter.]
(2)
Setbacks are measured to the building foundation, except where a portion of the building containing usable floor area extends beyond the foundation (such as on the upper floors in a garrison-style house). Where a building foundation is not present or not applicable, setbacks are measured to the most appropriate vertical fascia, eave board, or header joist for that part of the structure. For ground-mounted mechanical equipment, ground-mounted satellite dishes, fuel tanks, and bulkheads, setbacks are measured to the nearest part of the structure.
S.
Extensions beyond setbacks (i.e., into setback areas).
(1)
Appurtenant elements to buildings or structures which do not contribute to usable floor area and do not have a foundation and which are not specifically included in Subsection R above may extend into the setback areas but may not extend beyond any property line. This includes, but is not limited to, architectural trim, awnings, bay windows, chimneys, decorative architectural elements, downspouts, window air-conditioning units, exterior steps, fire escapes, gutters, place of refuge decks, building-mounted satellite dishes, roof eaves, siding materials, and vents.
(2)
In cases where any landing serving exterior steps exceeds 24 square feet in area, that landing (but not the steps) must meet all required setbacks.
T.
Triangular lots. Triangular lots shall contain one front lot line and two side lot lines.
U.
Triple frontage lots. On triple frontage lots, for the purpose of setbacks, there shall be established a front, two sides, and a rear. The ordinary front setback shall apply to that section of the lot which is deemed the front, as determined by the Director of Building, Zoning, and Licensing Services (based upon the locations of the front entrance, street address, path to the front, and driveway; E911 standards; the prevailing pattern of the other buildings on both blocks; impact upon the streetscapes; and other appropriate factors). For any side which faces a street the setback shall be the ordinary side setback in that district. The ordinary rear setback shall apply.