119-21 Tier II Requirements

The area of a private road shall be excluded from the area of the zoning lot for the purposes of applying the applicable requirements of Sections 23-14 (Open Space and Floor Area Regulations in R1 Through R5 Districts) or 23-15 (Open Space and Floor Area Regulations in R6 Through R10 Districts) as modified by this Section, and Sections 23-21 (Required Floor Area per Dwelling Unit) and 33-10 (FLOOR AREA REGULATIONS). For the purposes of this Section, the area of the private road shall include the area of the paved roadbed plus a seven-foot wide area adjacent to and along the entire length of the required curbs.

The maximum permitted percentage of lot coverage on a zoning lot shall be determined by Table I or Table II of this Section, as applicable.

TABLE I

PERMITTED PERCENTAGE OF LOT COVERAGE ON A ZONING LOT BY ZONING DISTRICT, AVERAGE PERCENT OF SLOPE AND RESIDENCE TYPE

If an authorization is granted for a development, enlargement or site alteration on a zoning lot or portion of a zoning lot having a steep slope or steep slope buffer pursuant to Section 119-311, the maximum permitted percentage of lot coverage for said zoning lot shall not exceed the maximum set forth in Table II of this Section.

TABLE II

PERMITTED PERCENTAGE OF LOT COVERAGE ON A ZONING LOT OR PORTION OF A ZONING LOT WITH A STEEP SLOPE, BY ZONING DISTRICT AND RESIDENCE TYPE

However, the maximum permitted percentage of lot coverage on a zoning lot, as determined by Table I or Table II, shall not apply to any development, enlargement or site alteration that receives an authorization pursuant to Section 119-312 (Authorization of certain uses within the Special Hillsides Preservation District) and is located in a Commercial District.

The height and setback regulations set forth in Sections 23-63 (Height and Setback Requirements in R1 Through R5 Districts), 23-64 (Basic Height and Setback Requirements), 34-24 (Modification of Height and Setback Regulations), 35-62 (Commercial Districts With an R1 Through R5 Residential Equivalent) and 35-63 (Basic Height and Setback Modifications) shall not apply to buildings or other structures on Tier II sites within the Special Hillsides Preservation District. In lieu thereof, the height and setback regulations set forth in this Section shall apply.

No portion of a building or other structure shall penetrate a plane drawn parallel to the base plane at a height that is shown in Table III of this Section. For buildings with pitched roofs, height shall be measured to the midpoint of such pitched roof. For the purposes of this Section, the base plane, which is a plane from which the height of a building or other structure is measured in R2X, R3, R4 and R5 Districts, shall also be established in accordance with the provisions of Section 12-10 (DEFINITIONS) for buildings or other structures in R1, R2 and R6 Districts.

TABLE III

MAXIMUM HEIGHT OF A BUILDING OR OTHER STRUCTURE

^*or Residence District equivalent when the zoning lot is located within a Commercial District

^**buildings that utilize the regulations of Section 23-143, applying to a predominantly built-up area, shall not exceed a maximum height of 32 feet above the base plane.

With the exception of private roads and driveways, no grading shall take place beyond 15 feet of the location of a building foundation, measured from the foundation perimeter. The following grading requirements shall apply to all Tier II sites.

(a)        Cut slopes shall be no steeper than two horizontal to one vertical; subsurface drainage shall be provided as necessary for stability.

(b)        Where two cut slopes intersect, the corners shall be rounded with a minimum radius of 25 feet.

(c)        Fill slopes shall be no steeper than two horizontal to one vertical; fill slopes shall not be located on natural slopes 2:1 or steeper, or where fill slope toes out within 12 feet horizontally of the top of an existing or planned cut slope.

(d)        Excavating for fill shall be prohibited unless the material is obtained from a cut permitted under an approved grading plan obtained for some purpose other than to produce fill material, or imported from outside the Special Hillsides Preservation District.

(e)        Fills shall be compacted to at least 95 percent of maximum density, as determined by AASHTO T99 or ASTM D698.

(f)        All retaining walls or cuts with a total vertical projection in excess of three feet and associated with cut or fill surfaces shall be designed as structural members keyed into stable foundations and capable of sustaining the design loads.

(g)        The edge of any cut or fill slope meeting the grade existing on June 30, 1987, should be blended into such grade in a vertical or horizontal arc with a radius of not less than 25 feet.

(h)        The top and toe of any cut or fill slope, or where any excavation meets the grade existing on June 30, 1987, should be rounded in a vertical arc with a radius of not less than five feet.

(i)        Tops and toes of cut and fill slopes shall be set back from lot lines for a horizontal distance of three feet plus one-fifth the height of the cut or fill but need not exceed a horizontal distance of 10 feet; tops and toes of cut and fill slopes shall be set back from buildings and structures a horizontal distance of six feet plus one-fifth the height of the cut or fill but need not exceed a horizontal distance of 10 feet.

The provisions set forth in this Section and Section 119-213 (Grading controls) shall apply to driveways and to private roads that provide access to buildings developed after December 11, 1999. The provisions for private roads set forth in Section 26-20, inclusive, shall not apply. However, the provisions of Sections 26-31 through 26-34 shall apply for private roads in lower density growth management areas.

(a)        Driveways

(1)        the maximum grade of a driveway shall not exceed 10 percent;

(2)        the paved width of a driveway shall not exceed 18 feet; and

(3)        the maximum length of a driveway from a private road or street to an accessory parking space shall not exceed 80 feet.

(b)        Private roads

(1)        the maximum grade of a private road shall not exceed 10 percent;

(2)        the width of the graded section beyond the curb back or edge of pavement of a private road shall extend no more than three feet beyond the curb back or edge of pavement on both the cut and the fill sides of the roadway. If a sidewalk is to be installed parallel to the roadway, the graded section shall be increased by the width of the sidewalk plus no more than one foot beyond the curb back;

(3)        the paved width of a private road shall not exceed 30 feet;

(4)        curbs shall be provided along each side of the entire length of a private road and accessory parking spaces may be located between the required roadbed and curb;

(5)        a curb cut, excluding splays, from a street to a private road may be as wide as such private road;

(6)        curb cuts providing access from private roads to parking spaces shall not exceed the width of the driveway served and in no event shall exceed a width of 18 feet, including splays;

(7)        a minimum distance of 16 feet of uninterrupted curb space shall be maintained between all curb cuts;

(8)        no building permit shall be issued by the Department of Buildings without approval by the Fire Department regarding the adequacy of vehicular access to and within the development for fire safety. Such approval may include the modification of private road width as set forth in paragraph (b)(3) of this Section; and

(9)        for the purposes of applying the yard regulations of Section 26-31, the curb of the private road shall be considered to be the street line.

The City Planning Commission may by authorization or special permit, as applicable, pursuant to Section 119-30 (SPECIAL REVIEW PROVISIONS), allow modifications to, or waivers of, the requirements of this Section. The approval of the Fire Department regarding the adequacy of vehicular access to and within the development for fire safety shall be a condition precedent for any modification or waiver.

(a)        In any area of no disturbance, existing vegetation and topsoil shall not be removed, except in accordance with a tree protection plan or as authorized by the City Planning Commission, pursuant to the provisions of Section 119-313 (Modification of landscaping, tree preservation and tree planting requirements).

(b)        To the maximum extent possible, existing trees, shrubs and ground cover shall be retained. Vegetation may only be removed or destroyed as a result of a development, enlargement or site alteration, provided that:

(1)        it is located in areas to be occupied by buildings, private roads, driveways, areas for required accessory parking or within a distance of 15 feet of a building foundation and, provided that it is not practical to avoid such removal by adjustments in the arrangement of such buildings, private roads, driveways or required parking areas;

(2)        the continued presence of the vegetation would interfere with the growth or health of trees of six-inch caliper or more designated for preservation and belonging to a species listed in Appendices A, B or C;

(3)        the continued presence of the vegetation would create special hazards or dangers to persons or property, which would not be possible or practical to eliminate by pruning or routine maintenance; or

(4)        an authorization has been granted by the City Planning Commission under the provisions of Section 119-313 approving the removal of such vegetation.

(c)        Any vegetation or topsoil that cannot be preserved as a result of a proposed development, enlargement or site alteration and is not permitted to be removed under paragraph (b) of this Section shall be replaced as follows: for every square foot of lot area of removed vegetation or topsoil, there shall be provided the following plantings of the size and number indicated in paragraphs (c)(1) through (c)(4) of this Section. The area of removed vegetation shall be measured so as to include any portions of the zoning lot that were located within the critical root zone of a removed tree of six-inch caliper or more. Species of ground cover and shrubs shall be selected from Appendix A (Selection List for Ground Covers and Shrubs). Species of on-site trees shall be selected from Appendix B (Selection List for On-site Trees).

(1)        Ground cover shall be planted one at one foot on center and at the rate of one plant for every square foot of lot area of removed vegetation; and

(2)        Large trees shall be planted at the rate of one three-inch caliper tree for every 500 square feet of lot area of removed vegetation; or

(3)        Small trees shall be planted at a rate of one eight-foot high tree for every 100 square feet of lot area of removed vegetation; or

(4)        Shrubs shall be planted at a rate of one gallon container-grown material for every 25 square feet of lot area of removed vegetation.

All developments, enlargements and site alterations on Tier II sites shall comply with the following tree planting requirements, whether or not existing vegetation is removed as a result of such development, enlargement or site alteration. However, the requirements set forth herein shall not apply to an enlargement of an existing building, provided that such enlargement does not increase the lot coverage of said building.

On-site trees, pre-existing or newly-planted, shall be provided on the zoning lot at the rate of one tree for each 1,000 square feet of lot area, or portion thereof, or shall equal a total of 51 percent of all tree credits for trees originally on site, whichever is greater.

For any existing tree of at least six-inch caliper that is preserved, credit for one tree shall be given for the first six inches of caliper and, for each additional four inches of caliper, credit for an additional tree shall be given.

Single-trunk trees newly planted to meet this requirement shall be of at least three-inch caliper at the time of planting. Multiple-trunk trees and low-branching coniferous evergreens shall be at least 10 feet in height at the time of planting. On-site trees shall be of a species selected from Appendix B (Selection List for On-site Trees).