National City Municipal Code Ch. 18.42 Building Design Standards

The purpose of standards for building design and materials is to focus efforts on good design in order to create a quality image for the city, making new buildings and building additions compatible with their surroundings, encourage reinvestment, and improve the city's economic vitality.

(Ord. No. 2024-2529, 4-2-2024)

Into setbacks and courts.

A. Requirements—General. Every required front, side, and rear setback shall be open and unobstructed from the ground to the sky, unless otherwise provided. In addition to permitted accessory buildings and structures, the following structures may be erected or projected into any required setback:

1. Fences and walls may be erected or projected into any required setback as provided in this section.

2. Cornices, belt courses, sills, eaves, or other similar architectural features (other than bay windows or vertical projections) may project into a required interior side setback not more than two inches for each one foot of width of such side setback, and may project into any other required setback, passageway or other open space not more than thirty inches, provided the width of an exterior side setback is not reduced to less than three feet.

a. Bay windows or other vertical projections may be permitted, subject to the limitations stated in Subsection (A)(2), provided that no floor area is added. This may be accomplished through a minimum thirty-six-inch gap between ground level and the lower limit of the projection, or some form of permanent interior physical limitation (cabinetry, counter, etc.). The projection may not be greater than thirty percent of the width of the elevation from which it projects.

3. Eaves may project into a required interior side setback not more than four inches for each one foot of width of such side setback, provided the width of such side setback is not reduced to less than two and one-half feet. Eaves may also project into any other required setback, passageway or other open space not more than thirty inches, provided the width of an exterior side setback is not reduced to less than two and one-half feet.

4. Chimneys may project into a required setback, passageway or other required open space not more than two feet, provided the width of any required side setback is not reduced to less than three feet.

5. Fire escapes may project into any setback not more than four feet.

6. Open unenclosed stairways or balconies, not covered by a roof or canopy, may project into a required rear setback not more than four feet, and into a required front setback, exterior side setback side or other required open space not more than thirty inches, provided the width of an exterior side setback is not reduced to less than two and one-half feet.

7. Open, unenclosed porches, platforms or landing places, including access stairways, not covered by a roof or canopy, which do not extend above the level of the first floor of the building, may project into any required setback passageway or other open space not more than four feet, provided that in no event shall any such porch, platform or landing place be more than four feet above the adjacent natural ground level.

8. A one-story unenclosed breezeway, not over five feet in width, extending from a main residential building to an accessory parking or other accessory structure, may project into a required rear or exterior side yard setback a distance not to exceed the required setback of the accessory structure.

9. Awnings or canopies without enclosing walls or screening may be attached to the exterior walls of a residential structure provided that:

a. Such awnings or canopies do not extend more than four feet into a required front setback and have no vertical support within the setback or space;

b. Such awnings or canopies do not extend more than thirty inches into a required side setback, rear setback, or other required open space, but in no event nearer than thirty inches to an interior lot line;

c. Where such awnings or canopies project into a required front or side setback or other required open space, they may extend only over the windows or doors to be protected and for twelve inches on each side thereof.

10. Entry arbors, either freestanding or as part of a fence as provided for in this section.

11. Air conditioning units, water heaters and required screens or enclosures.

(Ord. No. 2024-2529, 4-2-2024)

A. Conditions. Accessory structures and uses may be developed as permitted in this title, provided they are located on the same lot or parcel of land and are incidental to and do not substantially alter the character of the principal permitted use.

B. Alteration. No accessory structure shall be structurally altered, converted, enlarged or maintained for the purpose of providing a second dwelling units unless such accessory structures are made to conform to all regulations of this title for new structures.

C. Westside Specific Plan. Accessory structures in the RS-4 zone shall maintain a three-foot setback from the side lot line and the rear lot line and a minimum of six feet between structures but shall not be located in the front yard setback required except as provided by this title.

(Ord. No. 2024-2529, 4-2-2024)

A. Standards Applicable to All Zones.

1. All mechanical equipment located at ground level shall be enclosed within a permanent noncombustible enclosure subject to the approval of the building official, and subject to all yard and setback regulations.

2. All elevator housing and mechanical equipment located on the roof of any building shall be screened from adjacent views and contained within a completely enclosed penthouse or portion of the same building having walls and roofs with construction and appearance similar to the building served by the equipment and other appurtenances.

3. All accessory equipment, including air conditioning systems, dryers, exhaust or make up air, and similar systems, shall be completely screened with a parapet wall and shall be colored/painted the same color as the surface on which it is mounted or adjacent to.

(Ord. No. 2024-2529, 4-2-2024)

A. Applicability. This section provides standards for commercial buildings including retail, service, office, and institutional buildings in any zone where they are permitted.

B. Commercial Retail Buildings.

1. Large Format Retail or Anchor Stores.

a. Ground floor facades that face public streets shall have arcades, pergolas or galleries; display windows, accentuated entries or entry pavilions; awnings; raised planters; or special corner treatments such as towers, turrets, angled corners with parapets, or similar architectural treatments on at least sixty percent of the total facade length.

b. Facades greater than one hundred twenty feet in length measured horizontally shall incorporate wall plane projections or recesses having a depth of at least two percent of the length of the facade and extending at least twenty-five percent of the length of the facade.

c. A minimum of twenty-five percent transparency (clear vision glass) is required on the ground floor of a large format retail or anchor store.

2. Freestanding or "Pad" Buildings.

a. Freestanding retail buildings fronting a sidewalk shall be provided with sufficient display windows meeting the transparency requirements identified in Subsection (C)(3) below.

b. Freestanding retail or "pad" buildings within centers (multi-tenant strip developments) that do not front on a public street shall exhibit a minimum of a fifty percent window to fifty percent wall on at least three building facades.

3. Retail Shops/Multi-Tenant Development.

a. Buildings facades within a multi-tenant development must provide a repeating pattern that shall include at least one of the following elements at horizontal intervals of no more than thirty feet:

i. Color change;

ii. Texture change;

iii. Material change; or

iv. Structural bay expression through a change in plane no less than twelve inches in width such as an offset, reveal, or project rib.

b. Retail storefronts set back from a street with parking in front shall provide a minimum sixty percent transparency through the use of clear vision windows and doors when located along a sidewalk, building arcade or gallery.

c. Doors and windows mounted flush with the wall surface shall not be used unless in conjunction with an arcade or covered walkway. Doors and windows shall be set back in their wall openings to reveal the thickness of the wall when an arcade or covered walkway is not provided.

C. Building Aesthetics and Materials.

1. Articulation is required to reduce the mass and scale of large monolithic commercial buildings. Articulation is required on at least three sides of a building's facade by use of color, changes in materials, arrangement of facade elements (such as insets, offsets or varying setbacks, canopies, window recesses, arches, arcades or colonnades, varied roof planes, vertical projections, and fenestration). The service side of a building's facade shall not require the same articulation unless it is visible from an adjacent street, park or open space or residential/residentially-zoned area.

2. Any side of an office, commercial and institutional building visible from or adjacent to residential areas or residentially zoned lands shall be treated in the same manner as the street facing facade.

3. For buildings that front on a public right-of-way, internal private street or private drive intended to function as a street, the following minimum standards for transparency or clear vision glass are required:

a. Ground floor retail: Sixty percent.

b. Upper story retail: Forty percent.

c. Ground floor office or institutional: Fifty percent.

d. Second floor office or institutional: Thirty-five percent.

4. Rooflines.

a. Both single and multi-tenant buildings shall have variations in the rooflines and roof features that are consistent with the buildings mass and scale. Roofs shall meet at least two of the following requirements:

i. Decorative parapets that are a minimum of three feet in height.

ii. A three-dimensional cornice treatment a minimum of twelve inches in height.

iii. Overhanging eaves that extend at least two feet beyond the building facade.

iv. Three or more roof planes.

v. Any other treatment that in the opinion of the planning division, meets the intent of this section.

5. Exterior facades of new buildings should be constructed of materials which will withstand the abuses of weathering and possible defacing due to vandalism. These materials should be easily maintained and attractive from any distance. In the commercial and mixed-use zones, the exteriors of all buildings or accessory structures shall be constructed of stucco, masonry, architectural concrete masonry units, pre-cast concrete, rock, and/or wood or wood simulated siding; provided, however, that all buildings or structures shall have an integrated color or painted exterior.

a. Metal for use as a primary exterior building material is not permitted. The use of metal is permitted only as an accent material and may not exceed ten percent of each building facade face.

b. Building fronts shall incorporate and present either a finished parapet or overhang to the street.

c. All roof edges shall be finished with facia and/or combination fascia gutter.

d. Finished soffits are required.

e. The use of decorative materials to enhance the aesthetic appearance of the building or structure shall be required on any portion of the building or structure abutting upon a public street.

6. The exterior walls of all buildings or structures constructed within the commercial and mixed-use zones shall be of new material; provided, however, that quality used materials such as rock, red brick, or decorative masonry may be permissible. Other forms of architectural treatment of used materials may be approved by the planning division.

7. Color.

a. The use of colors on the exterior of a building shall be limited to an appropriate and complementary palette.

b. Large areas of intense white color shall be avoided except on rooftops.

c. The color palette chosen for a building should be compatible with the colors of adjacent buildings except where existing buildings strongly diverge from these standards.

d. Fluorescent or neon colors shall be avoided.

8. Accessory structures shall have compatible architectural details, design elements, and roof designs as the primary structure.

9. Trash and recycling enclosures.

a. Standards are found in Title 7, Section 7.10.080 (Enclosures required).

b. Enclosures shall be provided with receptacles for both rubbish and recyclable materials.

c. Enclosures shall be constructed with a roof.

D. Prohibited Exterior Wall Materials. The following materials are prohibited as a primary exterior wall material:

1. Unfinished concrete and concrete block, except split-face concrete block or slump block.

2. Corrugated metal, standing seam metal, or other metal wall materials.

3. Reflective mirror-type glass.

4. Plywood, including T-11 or similar wood products.

5. Imitation "rock work" veneer.

6. Corrugated fiberglass.

7. Asphalt shingles.

8. Plastic or plastic laminates.

E. Prohibited Roofing Materials. The following materials are prohibited for use as a roofing material:

1. Corrugated metal.

2. High contrast or brightly colored glazed tile, except where desirable for accent purposes.

3. Highly reflective surfaces.

4. Aluminum sheet metal.

(Ord. No. 2024-2529, 4-2-2024)

A. Building Aesthetics and Materials.

1. Long unbroken building facades shall be avoided. Facades with varied front setbacks shall be required.

2. Warehouses shall avoid blank front and exterior side wall elevations on street frontages through the use of building indentations and architectural details.

3. Building entrances to industrial use buildings shall be enhanced with architectural elements and landscaping for emphasis.

4. Materials.

a. All buildings and structures shall be constructed of metal, stucco, masonry, architectural concrete masonry units, pre-cast concrete, rock, and/or wood or wood simulated siding, and shall have an integrated color or painted exterior.

b. Thirty percent, including doors, of the gross area, to a twelve-foot height, of any building or structure abutting on the front or exterior side yard of a lot shall be constructed of, or surfaced with, glass, stone, wood, brick, and/or decorative masonry as architectural treatment to increase the aesthetic appearance of the building. On a corner lot, if the treatment required on the exterior side yard is concentrated on the corner of the building or structure and is located nearest the corner of the intersecting streets, the percentage of required area for decorative purposes may be reduced on the exterior side yard to ten percent.

c. Where the end use of any building or structure prohibits the use of decorative materials in either the front or exterior side of any building or structure or it is not economically feasible to use decorative materials, a color combination of the exterior surface of integrated or painted finish may be permitted, subject to site plan review.

d. The exterior walls of all buildings or structures in the industrial zones shall be of new material; provided, however, that quality used materials such as rock, red brick, or decorative masonry may be permissible. Other forms of architectural treatment of used materials may be approved by the planning division.

e. Metal buildings shall have the architectural appearance of conventionally built structures and an exterior surface that includes stucco, plaster, glass, stone, wood, brick, decorative masonry, or wood sheathing.

5. Trash and recycling enclosures.

a. Standards are found in Title 7, Section 7.10.080 (Enclosures required).

b. Enclosures shall be provided with receptacles for both rubbish and recyclable materials.

c. Enclosures shall be constructed with a roof.

(Ord. No. 2024-2529, 4-2-2024)

A. Multi-Unit Residential Building Design Standards.

1. The exterior design, height, and bulk of multi-unit projects should not negatively impact adjacent lower density residential areas.

2. Facade and Roof Articulation. A structure with three or more attached units should incorporate wall and roof articulation to reduce apparent scale. Changes in wall planes and roof heights, and elements such as balconies, porches, arcades, dormers, and cross gables can avoid a barracks-like quality. Long flat walls and roofs shall be avoided. Secondary hipped or gabled roofs covering the entire mass of a building are preferred.

3. Scale. Because multi-unit projects are usually taller than one story, their bulk can be imposing on surrounding uses. Structures with greater height may require additional setbacks at the ground floor level and/or upper levels.

4. Balconies Porches or Patios as Part of Multi-unit Structures are Required. These elements shall be used to break up large wall masses, offset floor setbacks, and add human scale to structures, and increase neighborhood safety by providing opportunities for "eyes on the street." Individual unit entrances within a multi-unit project shall have individual covered porches.

5. Trash and Recycling Enclosures.

a. Standards are found in Title 7, Section 7.10.080 (Enclosures required).

b. Enclosures shall be provided with receptacles for both rubbish and recyclable materials.

c. Enclosures shall be constructed with a roof.

6. Laundry Facilities. For multi-unit residential projects containing nine units or more that do not provide a washer and dryer for each unit, the following laundry facilities shall be provided: one washer and one dryer for each twenty dwelling units. The minimum requirement shall be one washer plus one dryer for multi-unit residential projects containing nine to twenty dwelling units.

7. Storage Space. In all multi-unit residential projects, a storage space of not less than one hundred fifty cubic feet for each unit plus fifty cubic feet for each additional bedroom more than one. The cubic feet utilized by mechanical equipment (e.g., water heater, furnace, etc.) may not be included in the cubic footage requirement. A bedroom closet shall not be included in the cubic footage requirement.

B. Mobile Homes/Factory-Built Housing.

1. Definition. Factory-built housing includes modular housing and residential structures certified under the National Mobile Home Construction and Safety Standards Act of 1974 and as defined in 798.3 of the Civil Code. All factory-built housing and the lot on which it is placed shall comply with all applicable provisions of Title 18 of the National City Municipal Code and the Design Guidelines.

2. Eligibility. A mobile home shall not be located on a permanent foundation, on a private lot, unless it:

a. Was constructed after September 15, 1971, and was issued an insignia of approval by the California Department of Housing and Community Development or was constructed after July 1, 1976, and was issued an insignia of approval by the U.S. Department of Housing and Urban Development; and

b. Has not been altered in violation of applicable codes.

3. Criteria. Mobile homes placed on a permanent foundation system, on a private lot, shall:

a. Be occupied only as a residential use type;

b. Meet all requirements for the zone in which located;

c. Be attached to a foundation system in compliance with all applicable building regulations and Section 18551 of the Health and Safety Code;

d. Have a minimum width of twenty feet;

e. Be covered with an exterior material customarily used on conventional dwellings and approved by the planning division pursuant to site plan review. The exterior covering material shall extend to the ground, except that when a solid concrete or masonry perimeter foundation is used, the exterior covering material need not extend below the top of the foundation;

f. Have a roof consisting of shingles or other material customarily used on conventional dwellings;

g. A mobile home may be required to have a porch, eaves or roof with eaves when it is determined, pursuant to site plan review, it is necessary to have it compatible with the dwellings in the area.

4. Foundation System. The most recently adopted California Building Code specifies regulations for the mobile home foundation system. These regulations provide:

a. Foundation system definition. A "foundation system" is an assembly of material constructed below, or partly below grade, not intended to be removed from its installation site, which is designed to support the structure and engineered to resist the imposition of external natural forces;

b. That mobile home foundation systems be designed in accordance with the provisions of the most recently adopted California Building Code, and local soil conditions. Design conditions for roof, wind, and seismic loads applicable to permanent building foundations shall be applicable to the mobile home foundation system;

c. The mobile home shall be installed in accordance with installation instructions provided by:

d. The manufacturer of the mobile home; or

e. A California-licensed architect or engineer for an individual mobile home where manufacturer's installation instructions are not available;

f. That both the foundation system and connection of the mobile home to the foundation system shall be capable of withstanding the design loads and concentrated loads identified in the installation instructions;

g. A foundation system plan shall be provided in addition to the installation instructions. The foundation system plan may be:

i. Provided by the mobile home manufacturer either as a part of, or separate from, the installation instructions;

ii. Provided by the installation contractor;

iii. Required to be signed by a California-licensed architect or engineer;

iv. A foundation system plan approved by the California Department of Housing and Community Development will be accepted.

5. Utility Connections. The mobile home electrical, gas, water and drain connections shall be made permanent in a manner applicable to permanent buildings. Gas shut-off valves, meters and regulators shall not be located beneath the mobile homes.

6. Surrender of Registration. Prior to occupancy, the owner shall request a certification from the planning division that a certificate of occupancy be issued pursuant to Section 18551(b)(2) of the California Health and Safety Code. Thereafter, for an existing mobile home, any vehicle license plate, certificate of ownership and certificate of registration issued by a state agency is to be surrendered to the appropriate state agencies.

7. Park and School Fees. Mobile homes placed on a permanent foundation shall be subject to local park and school fees in the same manner as conventional single-family dwellings.

8. Modification of Criteria. Modification of the criteria set forth in this section may be granted by the planning division if the site plan review finds that such modification will not be detrimental to the public interest or surrounding residents or properties. No such modification may be granted from Subsections (3)a, (3)b, and (3)c of this section.

9. Additions. Additions to a mobile home placed on a permanent foundation shall be made in accordance with all applicable laws, codes, and ordinances enforced by the city, and installation instructions provided by (site plan review required):

a. The manufacturer of the mobile home; or

b. A California-licensed architect or engineer; or

c. A building addition plan approved by the California Department of Housing and Community Development.

C. Single-family Infill Standards.

1. Architectural Considerations.

a. New single-family projects should incorporate the distinctive architectural characteristics of surrounding development, for example: window and door detailing, decoration, materials, roof style and pitch, finished-floor height, porches, bay windows, dormers, chimneys, balconies, shutters, decorative molding, and similar architectural details.

b. Rooflines of building additions shall be constructed to integrate the addition with the existing building. Contrasting rooflines which emphasize the separate construction of the addition, such as shed roofs extending from the wall of a structure with a hip or gable roof are prohibited.

c. Exterior materials, window details, and colors of building additions should match those of existing structures.

d. Roof pitches in common use in the residential neighborhood are gable and hip. New residential construction and additions should incorporate roofs which are compatible with the existing neighborhood style. Minimize the use of flat roofs unless the surrounding context suggests their use, or the structure being added on to has a flat roof.

e. Walls should be of either wood or simulated wood clapboard or stucco where the style and context would allow it. Brick or stone is recommended as an accent material. Clay tile is also a very suitable material for roofs and accents, but very shiny glazed roof tile should be avoided.

f. If concrete block is used for exterior wall construction, it shall receive a finish coat of stucco.

g. While two-story construction is considered acceptable in single-story neighborhoods, the structure should incorporate both vertical and horizontal variations in the wall planes in order to reduce the overall bulk of the project and develop a smaller scale to be compatible with adjacent single-story structures.

h. The use of any roof mounted equipment is highly discouraged for single-family units. If alternatives are not feasible, equipment must be screened from view in a manner which blends with the architectural style of the house, including use of materials and colors.

2. Site Design Considerations.

a. New development should continue the functional, on-site relationships of the surrounding neighborhood. For example, in many older neighborhoods, common patterns that should be continued are entries facing the street, front porches, and parking at the rear.

b. Front setbacks for new single-family development in existing neighborhoods should be either:

i. Equal to the average setback of all residences and buildings on both sides of public streets within one hundred feet of the property lines of the new project or

ii. Equal to the average of the two immediate adjacent buildings.

c. In cases where averaging between two adjacent existing buildings is chosen, the new building may be averaged in a stepping pattern.

d. Side yard setbacks in the neighborhood create a certain rhythm along the street. New projects or additions should be respectful of the open space pattern created by these setbacks.

e. Single-family residences located in non-residential and mixed-use zones shall maintain the same setbacks as the RS-2 zone. Lots with up to three single-family detached homes shall maintain the same setbacks as the RS-3 zone.

(Ord. No. 2024-2529, 4-2-2024)