Part 5. Combining and Overlay Districts
Chapter 18.130
(H-I) HILLSIDE COMBINING DISTRICT
Sections:
18.130.020 Establishment and designation.
18.130.040 Area and lot width requirements for residential districts only.
18.130.050 Development standards.
18.130.080 Methods for measuring natural land slope in residential districts.
18.130.090 Other requirements – On-site parking.
18.130.010 Purpose.
The purpose of the (H-I) combining district is to promote and encourage the orderly and safe development of hillside areas of the city by the application of regulations and requirements established to meet the particular problems and challenges associated with development of hillside areas. (Ord. 490 § 2; Ord. 1512 § 2, 8-3-82; Ord. 2528 § 1, 12-16-03; Ord. 2528 § 1, 12-16-03. 1990 Code § 8-21820.)
18.130.020 Establishment and designation.
(a) An (H-I) district may be established only in conjunction with other districts, except P (planned districts) and O-S (open space districts). An (H-I) designation is applicable to the area in which an (H-I) district is established.
(b) The provisions of this chapter shall apply in an (H-I) district, which district shall also be subject to other provisions of this title, including the provisions applicable to the particular district to which the (H-I) district designation is added and combined; provided, that where conflict between regulations occurs, the regulations specified in this chapter shall prevail.
(c) Whenever an (H-I) district is established, any subsequent application to change the district with which the (H-I) district is combined shall not be construed to be an application to eliminate the (H-I) district for the area covered by the application, unless such intent to eliminate the (H-I) district is expressly stated to be part of the application. (Ord. 490 § 2; Ord. 1512 § 2, 8-3-82; Ord. 21-2005 § 9(Exh. A-18), 7-26-05. 1990 Code § 8-21821.)
18.130.030 Land constraints.
Within the (H-I) district there may be lands on which development capacity is limited because of conditions detrimental to the public health, safety and welfare. The following shall be considered as constraints for development:
(a) Areas identified by the general plan, or any element thereof, or by an on-site soils and geologic investigation as having any of the following characteristics:
(1) Severe soil instability.
(2) Class VIII soil as classified by the Natural Resources Conservation Service of the United States Department of Agriculture.
(3) Groundwater conditions that may affect or be affected adversely by such construction.
(b) Lands that the city engineer or building official reasonably finds, based upon the evidence before him or her, are a landslide, in the path of a landslide, at risk of a landslide, or in an area of slope instability. The evidence to be considered by the city engineer or building official may include any or all of the following:
(1) Fremont general plan;
(2) An on-site geotechnical report;
(3) A survey by the United States Geological Survey;
(4) A survey by the California Geologic Survey;
(5) A report available to the city; or
(6) Observation of physical conditions.
However, in those cases where, based on a detailed site-specific geotechnical report, the city engineer or building official finds that the constraint is capable of reasonable mitigation and development of the area can occur consistent with this chapter, then for purposes of the proposed development, the area shall not be considered as constrained land; provided, however, that any correction of constrained areas shall not result in lands within the hill face open space being redesignated as unconstrained land. Such site-specific geotechnical report shall be prepared by a California licensed professional and the scope of such report determined by the city engineer or building official based on the type of development or construction proposed and the constraints to the land. The city engineer or building official may require that the report be peer reviewed and found acceptable by an independent geologist selected by the city engineer or building official, with the costs borne by the applicant.
(c) Lands having slopes in excess of 30 percent; provided, however, that minor encroachments onto slopes in excess of 30 percent may be permitted for lands below the toe of the hill1 line, where the planning manager or planning commission, where appropriate, finds and determines that the proposed encroachment will not conflict with the purposes and intent of this chapter.
(d) Lands not restricted by constraints that are inaccessible as a result of having to take access over or across constrained lands, as defined herein. For lands located above the toe of the hill1 line, the following shall apply:
(1) Where a preexisting roadway, which is not exempt pursuant to subsection (d)(3) of this section, is proposed to provide access, the slope being crossed is calculated based upon the natural slope as it existed prior to development of the roadway.
(2) Where a new roadway is proposed to provide access, the slope being crossed is calculated based upon the natural slope of the area.
(3) This subsection (d) shall not apply to lands accessible from existing public streets or approved private streets that cross slopes of 30 percent or more. (Ord. 1280 § 1, 10-3-78; Ord. 1512 § 2, 8-3-82; Ord. 1826 § 2, 6-28-88; Ord. 2528 § 2, 12-16-03; Ord. 21-2005 § 9(Exh. A-18), 7-26-05; Ord. 5-2008 § 14, 4-1-08; amended during 2012 reformat. 1990 Code § 8-21821.1.)
18.130.040 Area and lot width requirements for residential districts only.
The following requirements shall apply in an (H-I) district, except that the following provisions for increasing lot area or lot width shall not apply for lots four acres or greater in size:
(a) Lot Area. The minimum lot area shall be the minimum lot area of the residential district with which the (H-I) district is combined, increased two percent in area for each one percent of land slope in excess of six percent (disregarding minor surface humps and hollows); provided, that the maximum total increase required shall not exceed 50 percent for any lot with 30 percent or greater slope if the appropriate subdivision approval authority determines that a practical building site exists within the boundaries of the lot.
(b) Lot Width. The minimum lot width shall be the minimum lot width of the residential district with which the (H-I) district is combined, increased two percent in width for each one percent of land slope in excess of six percent (disregarding minor surface humps and hollows); provided, that the maximum total increase required shall not exceed 50 percent for any lot with 30 percent or greater slope if the appropriate subdivision approval authority determines that adequate access from a public or approved private street can be provided to the building site. The provisions of this subsection shall be applicable irrespective of the fact that they may necessitate an increase in lot area over and above that required pursuant to subsection (a) of this section. (Ord. 490 § 2; Ord. 1020 § 2, 1-7-75; Ord. 1512 § 2, 8-3-82. 1990 Code § 8-21822.)
18.130.050 Development standards.
(a) Development projects shall be reviewed according to the architectural and site design standards in this section. Development located within the hill area1 shall be reviewed according to the performance standards of the open space district, Section 18.55.040, as well as the development standards contained in this section. In cases where there is conflict between standards, the performance standards in the open space regulations shall prevail.
(b) All structures shall be designed to conform to the contours established with a grading plan. Structures shall be planned to minimize any grading outside the structure’s foundation and driveway. Structures shall be designed to fit the land, instead of modifying the land to fit the structure.
(c) Building mass and patterns of tree cover shall recognize views of adjacent properties and minimize the blocking of such vista corridors. Needless obstructions to view corridors shall be deemed a potential basis for denial.
(d) The height of the roof for any section of the building shall not exceed 30 feet above the grade established by the approved as-built grading plan or the individual lot’s approved as-built grading plan. Building height is established by a horizontal plane which is parallel to the ground as established by the approved as-built grading plan or the individual lot’s approved as-built grading plan. When a basement is used, or when there is grading for the creation of crawl space entirely under the building floor and not visible from the exterior of the building, the height shall be measured to the grade established by the approved as-built grading plan or the individual lot’s approved as-built grading plan (thereby excluding these spaces from the height calculation).
The planning manager may approve a building height greater than 30 feet for property located below the toe of the hill1 line, pursuant to the requirements set forth in Chapter 18.240, provided all the following findings can be made:
(1) The increase would enhance the architectural character of the structure;
(2) The increase would not unduly restrict the view from adjacent buildings;
(3) The increase would not exceed 15 percent of the total roof area as seen in plan view;
(4) The building design is unduly constrained by the 30-foot height limit because of significant topographic conditions of the lot.
(e) In no case shall the height of the ridge of any section of a structure exceed 18 feet above the finished grade when that portion of the structure is located on a ridge, knoll, hilltop1 or ridgeline.1 For property located in the hill area1, structures may not be located on knolls, hilltops,1 ridgelines1 or where they will project into the visual plane of such land features, as viewed from public roads, trails, or other public places, unless there is no other building site on the parcel or contiguous parcel in common ownership.
(f) Foundation walls (pony walls) shall be no higher than six feet from the finished floor to the grade established by the approved as-built grading plan or the individual lot’s approved as-built grading plan.
(g) Decks shall include any structure which provides exterior usable space above grade which is wholly or partially supported by structure apart from the wall of the house. In no case shall decks be more than five feet above the grade established by the approved as-built grading plan or the individual lot’s approved as-built grading plan, exclusive of railings. Decks more than 18 inches above the ground shall be provided with a continuous screen wall that will conceal structural support.
(h) Visible retaining walls used to construct garage pads shall be limited to a retaining height of six feet. The sides of any exposed exterior retaining walls installed for this purpose shall be architecturally treated to be compatible with the house.
(i) Retaining walls not a part of the walls of the building shall not exceed a maximum height of three feet each from the grade established by the approved as-built grading plan or the individual lot’s approved as-built grading plan. The use of successive retaining walls for building pads shall not result in grading in excess of four feet at the building.
(j) Other than public or private street lights, exterior lighting shall be diffused or concealed in order to prevent illumination of adjoining properties or the creation of objectionable visual impacts on other properties or roadways.
(k) Antennas or other similar devices, including satellite dish antennas, shall not be placed on roofs, in front yards or side yards adjacent to roadways, and shall be shielded from view from any adjacent properties or roadways.
(l) Solid fencing may be used between adjoining structures and for privacy to a point 20 feet beyond the rear building line or as approved by the planning manager. Open fencing shall be used at all other locations unless solid fencing is deemed acceptable by the planning manager during the design review permit approval process. The design of all fencing requiring the issuance of a building permit shall be approved by the planning manager for design compatibility prior to the issuance of building permits.
(m) Where grading permits are required, a professional engineer registered in the state of California shall be retained to prepare final grading plans for each individual lot and upon the completion of the grading submit to the planning manager a statement that the as-built grading conditions do not deviate from the approved plan by more than one foot of vertical elevation.
(n) All exterior grading shall be accomplished using slopes no greater than three horizontal to one vertical. The city engineer may allow steeper slopes depending on the quality of the soils material involved and the nature of the surrounding terrain. Interior or temporary cuts may be as recommended by the soils engineer.
(o) Balconies from upper levels of single-family residences shall be cantilevered and shall be limited to 125 square feet in area per 40 linear feet of house dimension. A balcony as defined herein shall mean any exterior structure made of wood or other materials which provides usable space above the finished grade and which is wholly supported by or cantilevered from the walls of the house. Where balconies are designed to be an architectural extension of the structure, the requirement for cantilevering may be waived, subject to the approval of the granting authority.
(p) Garbage or trash containers shall be suitably concealed behind permanent screening fencing contiguous to the structure.
(q) All exposed metals, including flashings, chimneys, vents, crickets and metal window frames shall be treated to prevent bright or highly reflective surfaces. Designs which include bright or reflective accents shall not be permitted.
(r) Exterior color schemes shall avoid bright and contrasting colors. Colors chosen to blend with the natural landscape shall be required.
(s) Roof shape, color and texture shall harmonize with the color and architectural treatment of exterior walls. Structures with slightly sloping or flat roofs are not encouraged when the roof will be visible from above.
(t) Solar panels and appurtenances shall be designed to blend with the architectural design of the building and not be substantially visible from adjacent properties or adjacent rights-of-way.
(u) Accessory structures shall be designed to complement the primary structure, unless the accessory structure cannot be seen from neighboring properties or adjacent rights-of-way. In some instances, some landscape screening may be required to mitigate the visual impact of the accessory structure.
(v) Swimming pools and tennis courts shall generally be within natural grade, or four feet from any toe or slope of a compacted fill pad lot (line to be taken from approved grading plans). Any decks related to a pool or court shall be exclusive of the four-foot strip and shall be limited to five feet in height above grade, exclusive of railings.
(w) Appropriate landscaping1 may be required for developments in the hill areas1 as a means of reducing visibility from public places and assuring a harmonious blend of the natural and built environments.
(x) Development of legal parcels shall be limited to one dwelling unit per 20 acres until such parcels meet the water and sewer service levels established by the Alameda County water district and the Union sanitary district.
(y) The development shall be within an acceptable response time for police and fire.
(z) Public or private streets shall meet city standards, including those contained in the city’s hillside streets policy to provide safe and environmentally sound access.
(aa) Where water supply is by private well, a backup power source for the well shall be provided subject to the approval of the fire department.
(bb) In cases where development is being proposed to the planning commission within the hillside combining district or the general plan hill area,1 the planning commission may schedule a field trip in accordance with the commission’s bylaws and state law. (Ord. 2045 § 116, 9-21-93; Ord. 2504 §§ 8, 9, 7-15-03; Ord. 21-2005 § 9(Exh. A-18), 7-26-05; Ord. 5-2008 § 14, 4-1-08; amended during 2012 reformat; Ord. 9-2014 § 19, 3-4-14. 1990 Code § 8-21822.1.)
18.130.060 Additional procedures and standards for development of parcels crossed by the toe of the hill1 line where no subdivision of land is proposed.
(a) Development on a parcel 20,000 square feet or less in area shall be reviewed by planning division staff based upon a checklist to determine if the purposes of the Hill Area Initiative of 2002 are being affected. If it is determined that the proposed project could affect the purposes of the initiative, then the project would need to meet the requirements set forth in the initiative. If, however, it is determined that the project does not affect the purposes of the initiative, then the project may proceed in accordance with the zoning and other city standards established for the portion of the lot located below the toe of the hill1 line.
(b) For a parcel larger than 20,000 square feet in area, development located above the toe of the hill1 line shall comply with the provisions of the Hill Area Initiative of 2002, while development located below the toe of the hill1 line shall comply with the zoning and other city standards applicable to the area below the toe of the hill1 line. (Ord. 21-2005 § 9(Exh. A-18), 7-26-05. 1990 Code § 8-21822.2.)
18.130.070 Additional procedures and standards for development of parcels crossed by the toe of the hill1 line where a subdivision of land is proposed.
(a) For parcels less than 20 acres in size, all new lots located below the toe of the hill1 line shall be developed in accordance with the zoning, subdivision and other applicable city standards. If any new lots contain area located above the toe of the hill1 line, that area shall not count towards the minimum parcel size required by the zoning district below the toe of the hill1 line. That portion of a new lot, if any, located above the toe of the hill1 line shall be placed in an open space easement. The open space easement shall preclude development of all structures other than rural-appearing, open wire-style perimeter fencing. It is preferable that the area above the toe of the hill1 line be associated with as few new lots as determined feasible.
(b) If after subdividing the area below the toe of the hill1 line into conforming lots there remains an area equal to or greater than 20 acres (partially or fully above the toe of the hill1 line), an additional lot may be permitted for each 20-plus acre parcel proposed in accordance with the provisions of the Hill Area Initiative of 2002. (Ord. 21-2005 § 9(Exh. A-18), 7-26-05. 1990 Code § 8-21822.3.)
18.130.080 Methods for measuring natural land slope in residential districts.
The natural land slope for each individual lot is determined by measuring the distance and change of elevation within a minimum rectangle drawn within the lot boundaries. The minimum rectangles are developed by reducing the minimum lot widths and lengths by subtracting the required front, rear and side yards. The rectangle shall be located so that the proposed building site is contained within the rectangle.
Minimum rectangles for each standard single-family zoning district are as follows:
|
Width |
Length |
|
|---|---|---|
|
R-1-6 |
43 feet |
64 feet |
|
R-1-8 |
54 feet |
64 feet |
|
R-1-10 |
60 feet |
70 feet |
|
R-1-20 |
75 feet |
143 feet |
|
R-1-40 |
105 feet |
200 feet |
|
R-1-80 |
105 feet |
200 feet |
(Ord. 1020 § 3, 1-7-75; Ord. 1294 § 4, 11-28-78; Ord. 1512 § 2, 8-3-82. 1990 Code § 8-21823.)
18.130.090 Other requirements – On-site parking.
When a lot or parcel fronts or is proposed to front on a street where a curbside parking lane is not provided, on-site parking shall be provided as required by officially adopted hillside street standards. Such on-site parking may be located in required front yard areas if it is properly screened and if the planning commission finds that front yard parking will not be detrimental to the purposes or intent of this chapter. (Ord. 490 § 2; Ord. 513 § 6; Ord. 631 § 12; Ord. 1020 § 3, 1-7-75; Ord. 1261 § 1, 8-1-78; Ord. 1512 § 2, 8-3-82. 1990 Code § 8-21824.)
[Notes Applicable to Chapter 18.130]
1 This term is defined in Chapter 18.25.