Chapter 19.12


19.12.010    General.

19.12.020    Site features and context.

19.12.030    Building design and visual interest.

19.12.040    Landscape design and outdoor spaces.

19.12.050    Vehicular and pedestrian circulation.

19.12.060    Screening of service and mechanical areas.

19.12.070    Lighting.

19.12.080    Signs.

19.12.010 General.

A. Applicability. This chapter establishes design standards for regulated improvements in all zones established by MICC 19.01.040, except Town Center. Design standards for Town Center are set forth in Chapter 19.11 MICC. These standards are in addition to any other standards that may be applicable to development in the zone in which the development occurs. In the PBZ, the terms of the PBZ site plan as set forth in MICC 19.04.010 shall control; provided, to the extent not inconsistent with MICC 19.04.010, the provisions of MICC 19.12.010 [excluding (D)(2)(b) and (c)], 19.12.030, 19.12.060, 19.12.070 and 19.12.080 shall apply. These design standards are not intended to slow or restrict development, but to add consistency and predictability to the permit review process.

B. Design Vision.

1. Site and Context. Non-Town Center areas are largely characterized by residential settings that are heavily vegetated, topographically diverse and enhanced with short and long-range views that are often territorial in nature. The design of new and remodeled structures should respond to this strong environmental context. Site design should maintain the natural character of the island and preserve vegetation concentrations, topography and the view opportunities that make Mercer Island special.

2. Building Design. Development of new and remodeled structures should conserve Mercer Island’s special environmental characteristics, such as steep slopes, watercourses, and large concentrations of mature trees. Buildings shall be designed to be architecturally compatible with other structures in the neighborhood with respect to human scale, form and massing, and relationship to natural site features. High quality and durable materials, complementary colors, texture, and architectural detail should be incorporated into the design. Use of materials such as natural wood and stone, and design elements such as large building overhangs and window exposure to natural light, are encouraged.

3. Landscaping and Amenities. Landscaping should reflect the natural wooded character of Mercer Island and provide visual separation between different land uses. Amenities such as street trees, plantings, and other landscape design elements, including fountains or water features, and art features should be integrated into new and remodeled structures and their sites.

C. Applicant’s Responsibility. It is the responsibility of the applicant to design a project in compliance with the objectives and standards of this chapter and all other regulations applicable to the zone in which the development occurs.

D. Design Review Process. Design review shall be conducted by the city’s design commission or code official consistent with the process provided in MICC 19.15.040(F). The design commission or code official shall review each regulated improvement and determine each project’s conformance with the applicable objectives and standards of this chapter.

1. Full Application of Design Requirements: Major New Construction. All design requirements of Chapter 19.12 MICC shall apply, except as provided in MICC 19.01.050(D)(3)(a), when there is new construction from bare ground, or intentional exterior alteration or enlargement of a structure over any three-year period that incurs construction costs in excess of 50 percent of the existing structure’s current King County assessed value as of the time the initial application for such work is submitted; provided, application of Chapter 19.12 MICC shall not be construed to require an existing structure to be demolished or relocated, or any portion of an existing structure that is otherwise not being worked on as part of the construction to be altered or modified.

2. Partial Application of Design Requirements: Minor Exterior Modification. The following design requirements shall apply when there is a minor exterior modification, as defined in MICC 19.16.010:

a. MICC 19.12.030 pertaining to building design and visual interest;

b. MICC 19.12.040(B)(5), (6), (7), (8), (9) and (11) pertaining to landscape design and outdoor spaces: entrance landscaping; planting types; screen types and widths by use and location; perimeter landscape screens; surface parking lot planting; and general planting, irrigation and maintenance standards;

c. MICC 19.12.050 pertaining to vehicular and pedestrian circulation;

d. MICC 19.12.060 pertaining to screening of service and mechanical areas;

e. MICC 19.12.070 pertaining to lighting;

f. MICC 19.12.080 pertaining to signs;

The design requirements pertaining to structures shall be applied only to that portion of an existing structure that undergoes minor exterior modification and shall not require any portion of an existing structure that is otherwise not being worked on as part of the construction to be altered or modified.

3. Value Measure When Structure Has No Assessed Value. For purposes of determining when a project will be considered major new construction or minor exterior modification, and the threshold for application of design requirements as set forth in subsections (D)(1) and (2) of this section, if there is no current King County assessed value for a structure, a current appraisal of the structure, which shall be provided by the applicant and acceptable to the code official, shall be used as the value point of reference.

E. Shall/Should. When a standard uses the word “shall,” the standard is mandatory. When a standard uses the word “should,” the standard is mandatory unless the applicant can demonstrate, to the satisfaction of the design commission or code official, an equal or better means of satisfying the standard and objective.

F. Development Agreements. An applicant may request modifications to any design and development standards set forth in this chapter by requesting a development agreement consistent with RCW 36.70B.170 through 36.70B.210. All development agreements shall be in form and content acceptable to the city attorney and will be reviewed and either approved or rejected by the city council after a public hearing pursuant to RCW 36.70B.200. (Ord. 04C-08 § 1).

19.12.020 Site features and context.

A. Objectives.

1. To encourage design that respects natural landforms, mature trees, and sensitive areas and uses them to provide project identity.

2. To ensure site design is approached in a systematic and unified manner that takes advantage of inherent opportunities and complies with specific standards for building location and orientation.

3. To link open space and recreation areas, where feasible, with public open space, parks, and trails.

4. To encourage building and site designs that use natural elements which link new or modified development to the neighborhood.

5. To promote functional and visual compatibility and better transitions between different uses, adjacent neighborhoods, and between development and natural features.

B. Standards.

1. Site Features.

a. Landforms. Design and layout of the site should incorporate natural landforms such as trees, topography and water courses into proposed developments. Cut and fill should be minimized and preservation of mature trees should be maximized, particularly adjacent to project boundaries and steep slopes. Natural contours should be respected and retained where feasible.

2. Sloped or Hillside Development.

a. Building development should generally occur on the least steep portions of the site in order to conserve the more fragile areas for landscaping or general open space.

b. Structures built on substantial slopes or hillsides should be designed to minimize their visual impact on surrounding areas. Ridgelines of major slopes should not be broken by structures or loss of vegetative cover. Acceptable methods to integrate structures into the hillside include, but are not limited to, height control, stepped construction, muted earth tone colors, and tree preservation.

c. Building Orientation. Buildings should respond in design to a prominent feature, such as a corner location, a street or the lake. Buildings and site design should provide inviting entry orientation. Buildings should not turn their backs to the street.

3. Relationship of Buildings to Site.

a. Site Design. Site design and architectural style shall be pedestrian in scale and address interface with public rights-of-way, vehicular and pedestrian circulation.

b. Architectural Context. New development should reflect important design elements of existing structures in the neighborhood, including but not limited to, roof forms, materials and colors.

c. Multiple Structures. Variable siting of individual buildings, heights of buildings, and building modulation should be used in order to provide variety in site and specific building design.

d. Transitions to Neighborhoods. Proposed developments should transition with and not overpower adjoining permitted land uses through modulation of building facades, use of established setbacks, and installation of landscape buffers. Building designs should step down to lower heights adjacent to surrounding buildings.

e. Decorative Landmarks. Imaginative exterior features that complement and are integrated into the building design and create visual focal points that give identity to an area, such as special paving in pedestrian areas, art features, decorative clocks, or water features should be provided. (Ord. 04C-08 § 1).

19.12.030 Building design and visual interest.

A. Objectives.

1. To ensure high quality materials and finishes are used to bring a visually interesting experience to the streetscape.

2. To ensure that building design is based on a strong, unified, coherent, and aesthetically pleasing architectural concept.

3. To not restrict the design to a particular style.

4. To ensure that new buildings are appropriately designed for the site, maintain human scale, and enhance the architectural character of the neighborhood.

5. To ensure buildings are detailed, provide visual interest, do not have blank walls and that large buildings are modulated and articulated to reduce their apparent mass and scale.

6. To ensure high quality and durable buildings which will help to maintain and protect property values.

B. Standards.

1. Scale, Form and Mass. Scale, form, massing, building proportions, spacing of windows and doorways, roof silhouette, facade orientations, and style of architecture shall have a unified character and, as to commercial, regulated residential and regulated public facilities, recognize pedestrian needs.

a. Scale. Building scale should be proportional to other adjacent buildings, the street edge and, as to commercial, regulated residential and regulated public facilities, to the pedestrian environment.

b. Form and Mass. Building forms should not present visual mass or bulk impacts that are out of proportion to adjacent structures, or that appear from the public way or surrounding properties as having unmodulated visual bulk.

2. Building Facades – Visual Interest.

a. Facade Modulation. Building facade modulation shall break up the overall bulk and mass of the exterior of buildings and structures. Such modulation should always be addressed on the horizontal plane and the vertical plane. Large or massive buildings should integrate features along their facades that are visible from the public right-of-way, pedestrian routes and nearby structures to reduce the apparent building mass and achieve an architectural scale consonant with other nearby structures.

b. Modulation Guidelines.

i. Horizontal building facade modulation should occur at no less than every 50 feet of wall length. Forms of both vertical and horizontal building modulation may include, but are not limited to: facade indentations and extrusions; actual building separation; connecting atriums, courtyards and plazas; variable roof forms and overhangs; and decks and balconies.

ii. Building facades visible from public ways and public spaces should be stepped back or projected forward at intervals to provide a minimum of 40 percent overall facade modulation.

c. Ground Level Facades. Blank walls at the ground level that may be visible from a public view should be avoided. Ground level facades should create visual interest by utilizing features such as windows, wall articulation, arcades, trellises or other plant features.

d. Fenestration. Fenestration should be integrated in the overall building design and should provide variety in facade treatment.

e. Horizontal Variation and Emphasis. Building facades should be made more visually interesting through the use of reveals, medallions, belt courses, decorative tile work, clerestory windows, or other design features. The scale of the detail should reflect the scale of the building.

f. Signs. Building design should allow space for a wall sign, consistent with the provisions of MICC 19.12.080, Signs, if it is anticipated that a wall sign will be used.

3. Building Articulation. Design shall articulate building facades by use of variations of color, materials or patterns, or arrangement of facade elements that are proportional to the scale of the building. Architectural details that are used to articulate the structure may include reveals, battens, and other three dimensional details that create shadow lines and break up the flat surfaces of the facade.

a. Tripartite Articulation. Tripartite building articulation (building top, middle, and base) should be used to create human scale and architectural interest.

b. Fenestration. Fenestration should be used in facades visible from public ways and public spaces visible from public ways for architectural interest and human scale. Windows should be articulated with treatments such as mullions or recesses and complementary articulation around doorways and balconies should be used.

c. Architectural Elements. The mass of long or large scale buildings should be made more visually interesting by incorporating architectural elements, such as arcades, balconies, bay windows, dormers, and/or columns.

d. Upper Story Setback. Upper stories should be set back to reduce the apparent bulk of a building and promote human scale. When buildings are adjacent to single-family residential dwellings, upper story setbacks shall be provided from property lines.

4. Materials and Color.

a. Durable Building Exteriors. Building exteriors should be constructed from high quality and durable materials that will weather well and need minimal maintenance.

b. Consistency and Continuity of Design. Materials and colors generally should be used with consistency on all sides of a building.

c. Material and Color Variation. Color and materials should highlight architectural elements such as doors, windows, fascias, cornices, lintels, sills and changes in building planes. Variations in materials and colors should generally be limited to what is required for contrast or to accentuate architectural features.

d. Concrete Walls. Concrete walls should be architecturally treated. The enhancement may include textured concrete such as exposed aggregate, sand blasting, stamping or color coating.

e. Bright Colors. Bright colors should be used only for trim and accents. Bright colors may be approved if the use is consistent with the building design and other design requirements. Fluorescent colors are prohibited.

5. Building Entrances.

a. Architectural Features and Design. Special design attention should be given to the primary building entrance(s). A primary entrance should be consistent with overall building design, but made visually distinct from the rest of the building facade through architectural features. Examples include recessed entrances, entrances which roof forms that protrude from the building facade, and decorative awnings, canopies, porte-cocheres, and covered walkways.

b. Entrance Connections. The primary entrance to a building should be easy to recognize and should be visible from the public way and/or physically connected to the public way with walkways. Landscaping should reinforce the importance of the entrance as a gathering place and create visual and physical connections to other portions of the site and to vehicular and pedestrian access points.

6. Rooflines.

a. Roofline Variation, Interest, and Detail. Roofline variation, interest, and detail shall be used to reduce perceived building height and mass and increase compatibility with smaller scale and/or residential development. Roofline variation, interest and detail may be achieved through use of roofline features such as dormers, stepped roofs, and gables that reinforce a modulation or articulation interval, incorporation of a variety of vertical dimensions, such as multiplaned and intersecting rooflines, or flat-roofed designs that include architectural details such as cornices and decorative facings.

b. Roofline Variation, Numeric Standard. Roof line variation shall occur on all multifamily structures with roof lines which exceed 50 feet in length, and on all commercial, office or public structures which exceed 70 feet in length. Roof line variation shall be achieved using one or more of the following methods:

i. Vertical off-set ridge or cornice line;

ii. Horizontal off-set ridge or cornice line;

iii. Variations of roof pitch between 5:12 and 12:12; or

iv. Any other approved technique which achieves the intent of this section.

7. Additional Standards for Buildings Containing Residential Units. Buildings containing residential units should incorporate the following additional design elements to make them residential in character:

a. Bay windows, dormers, patios or decks;

b. Base articulation such as plinths; or

c. Other techniques approved by the design commission which make the building residential in character.

8. Corporate Design. Building and site design for chain or franchise businesses should use customized components consistent with the objectives and standards of this chapter. Specific icons or trademarks of a company may be used, but the overall design of the building and site must represent a development compatible with the neighborhood including its colors, materials, textures and treatment of design.

9. All-Weather Features. All-weather features at the sidewalk, courtyard or public gathering space areas of commercial and regulated public facilities, such as awnings, canopies, covered walkways, trellises, or covered patios, should be provided to make spending time outdoors feasible in all seasons.

10. Public schools should respect privacy for adjacent residential properties by providing appropriate screening and placement of windows in buildings. Distance from residential property lines should also be considered when determining the appropriate amount of screening and the type and placement of windows. (Ord. 14C-06 § 5; Ord. 04C-08 § 1).

19.12.040 Landscape design and outdoor spaces.

A. Objectives.

1. To ensure that landscape design reinforces the natural and wooded character of Mercer Island, complements the site, the architecture of site structures and paved areas, while enhancing the visual appearance of the neighborhood.

2. To ensure that landscape design is based on a strong, unified, coherent, and aesthetically pleasing landscape concept.

3. To ensure that landscape plantings, earth forms, and outdoor spaces are designed to provide a transition between each other and between the built and natural environment.

4. To ensure suitable natural vegetation and landforms, particularly mature trees and topography, are preserved where feasible and integrated into the overall landscape design. Significant trees and tree stands should be maintained in lieu of using new plantings.

5. To provide a vegetated screen between dissimilar uses, to screen surface parking areas from adjacent uses and public rights-of-way.

6. To ensure planting designs include a suitable combination of trees, shrubs, groundcovers, vines, and herbaceous material; include a combination of deciduous and evergreen plant material; emphasize native plant material; provide drought tolerant species; and exclude invasive species.

B. Standards. Any quantitative standards contained in MICC 19.12.040(B) that specify types of plant material, quantities, spacing, and planting area widths are not intended to dictate a rigid and formal landscape. The applicant should incorporate the quantitative standards into a quality landscape and planting design that meets the stated objectives and standards of this section.

1. Landscape Area. Landscape design shall address all areas of a site not covered by structures or used by automobiles. Landscape areas include open space, plantings, patios, plazas, pedestrian ways, trails, and other outdoor spaces. Surface parking lot planting and screening are required as set forth in MICC 19.12.040(B)(7), (8) and (9). Design review, however, shall be primarily concerned with: (a) areas of a site that require landscaping in order to address the impact of development on adjoining properties or public ways; and (b) parts of the development that are visible from adjoining properties or public ways.

2. Outdoor Spaces. Outdoor spaces should be designed at a human scale and include hardscape spaces, spaces created by plant materials and combinations of the two.

a. Strategically placed and useable pedestrian areas such as courtyards, plazas, outdoor seating or other gathering places should be provided for commercial, regulated residential and public facilities.

b. On-site recreation areas appropriate to the users should be provided for residential and public projects.

c. The design of outdoor spaces should combine necessary site functions, such as storm water detention, with open space and visual interest areas.

3. Architectural Features. The design of landscape architectural features should be in scale with and complement the architecture of site structures and the visual character of the neighborhood.

a. Use of architectural screens, arbors, trelliswork, art features, fountains and paving treatments such as wood, brick, stone, gravel and/or other similar methods and materials should be used in conjunction with native plant materials or in place of plant materials where planting opportunities are limited.

b. Fences should be made of ornamental metal or wood, masonry, or some combination of the three. The use of razor wire, barbed wire, chain link, plastic or wire fencing is prohibited if it will be visible from a public way or adjacent properties, unless there are security requirements which cannot feasibly be addressed by other means.

c. Fences should not create the effect of walled compounds that are isolated from adjacent developments and public ways.

4. Minimum Landscape Area Requirements.

a. Total Landscaped Area. The following minimum areas shall be landscaped:

i. Single-Family Residential (SF). For nonresidential uses in single-family residential zones (SF), a minimum of 35 percent of the gross lot area of shall be landscaped.

ii. Multifamily Residential (MF). In multifamily residential zones (MF-2, MF-2L, MF-3), a minimum of 40 percent of the gross lot area shall be landscaped.

iii. Planned Business Zone (PBZ). In the planned business zone (PBZ) landscape area requirements shall be as set forth in MICC 19.04.010.

iv. Commercial Office (CO). In commercial office (CO) zones, a minimum of 40 percent of the gross lot area shall be landscaped.

v. Business (B). In business (B) zones, a minimum of 25 percent of the gross lot area shall be landscaped; provided, for fuel stations, a minimum of 10 percent of the gross lot area shall be landscaped.

b. Impervious Surfaces. For all zones, area landscaped by impervious surfaces should constitute no more than 25 percent of the total required landscape area; provided, for multifamily residential zones, area landscaped by impervious surfaces should constitute no more than 10 percent of the total required landscape area.

5. Entrance Landscaping. For commercial and regulated public facilities, landscaping at entrances should frame an outdoor space near the entrance and reinforce this important building feature as a gathering place.

6. Planting Material, Types and Design. The following planting types should be used:

a. Native or northwest-adapted plants should be used for all open space and buffer locations and drought tolerant plantings should be used in a majority of plantings.

b. New plantings should complement existing species native to the Pacific Northwest.

c. Ground cover should be used to ensure planting areas are attractive, minimize maintenance and the potential for encroachment of invasive plant material. Ground cover should be planted and spaced to achieve total coverage within three years after installation.

7. Perimeter Screen Types and Widths by Use and Location.

a. Required Screen Types and Widths. The following screen types and widths should be used:


Adjacent to

Screen Type and Width




Institutional Use or Public Facility

Public Way


20 feet1, 2


Public Schools

Public Way


20 feet1



Single-Family Residential

20 feet1, 3, 4



Utility Development

Public Way


10 feet


Commercial or Multifamily outside of C-O Zone

Public Way



10 feet

All uses inside of C-O Zone

Public Way


20 feet


Commercial, Institutional, Utility or Public Facility

Residential (Single or Multifamily)

20 feet1



Institutional, Commercial, Utility, Public Facility


10 feet


Public Park

20 feet



Multifamily Development

Single-Family Residential


20 feet



Multifamily Residential


10 feet



Institutional, Commercial, Utility, or Public Facility


10 feet



Public Park

20 feet



All other private uses

Public Park

20 feet



1Breaks in full or partial screen planting may be allowed for institutional and public facilities to create focal points, preserve views, and highlight the prominence of important buildings.

2Perimeter landscape requirements may be modified if necessary to enable an existing public facility to make safety-related improvements to a legally nonconforming parking lot.

3School bus and student loading and unloading and primary parking areas located 100 feet or less from an abutting single-family zoned property shall provide a 30-foot-wide full screen. The number of trees required in the 30-foot-wide full screen area shall be 1.25 times the number otherwise required for a full screen. The design commission may modify screening width, location, height and number of trees to avoid casting shadows on adjacent residential properties or to accommodate existing storm detention systems and utilities.

4Owners of adjacent single-family zoned property shall be consulted on perimeter screen design and planting materials.

b. Perimeter Width Averaging. Averaging of screen widths may be allowed, if the objectives of this section, the minimum landscape area requirements set forth in MICC 19.12.040(B)(4) and the following criteria are met:

i. Plant material is clustered to more effectively screen parking areas and structures; and

ii. Significant trees are retained.

8. Perimeter Landscape Screens. Perimeter landscape screens should be consistent with the following definitions of screen types. Where existing undergrowth will be retained, the shrub and ground cover requirements for all screen types may be adjusted, provided the objectives of this section are met.

a. Full Screen. A full screen provides a dense vegetated separation between dissimilar uses on adjacent properties. A full screen should block views from adjacent properties as seen at the pedestrian eye level in all seasons within three years of installation. The number of trees provided shall be proportionate to one tree for every 10 feet of landscape perimeter length.

b. Partial Screen. A partial screen provides a moderate vegetated separation between uses on adjacent properties and intermittent views to adjacent properties. A partial screen shall provide the desired screening function as seen at the pedestrian eye level in all seasons within three years of installation. The number of trees provided shall be proportionate to one tree for every 20 feet of landscape perimeter length.

c. Filtered Screen. A filtered screen should provide in all seasons and within three years of installation a lightly vegetated visual separation between uses on adjacent properties and allow visual access to adjacent properties. When compared to the other screen types, a filtered screen should be characterized by more open spaces, light filtration and transparency through the plant material forming the screen.

9. Surface Parking Lot Planting. Surface parking lot planting is required in addition to required perimeter landscape screens. The requirements for surface parking lot planting for new parking lots with fewer than 20 spaces and for additions or remodels may be waived or modified if the applicant can demonstrate that these standards would reduce the amount of parking below the minimum required for the site.

a. Standards by Location. Surface parking lots not located adjacent to public rights-of-way should provide one tree for every six parking stalls. Surface parking lots located in the front of buildings or adjacent to public rights-of-way should provide one tree for every four parking stalls. Trees should be at least six feet high at the time of planting. All lots should have planting areas at the end of parking aisles.

b. Common Standards for Surface Parking Lot Planting. The following standards apply to all surface parking lot planting:

i. Shrubs. Shrubs should be maintained at a maximum three feet height within surface parking lots so views between vehicles and pedestrians will not be blocked. Irregular spacing and clustering is encouraged; however, the minimum number of shrubs shall be determined by assuming shrubs are planted on three foot centers throughout the entire planting area. Where vehicle headlights may project onto neighboring properties, shrubs shall be spaced to provide a continuous planting buffer.

ii. Planting Islands or Strips. Planting islands or strips should have an area of at least 80 square feet and a narrow dimension of not less than five feet if wheel stops are provided to prevent vehicle overhang. A narrow dimension of not less than eight feet may be provided if the vehicle overhang area is included in the planting area.

iii. Tree Location. In parking lots, trees should be planted no closer than four feet from pavement edges where vehicles overhang planted areas. Curb stops may be used to proportionally decrease this distance.

iv. Narrow Planting Strips and Parking Spaces. Narrow parking lot islands or peninsulas and planting strips shall not be planted in sod. Location of wider parking spaces adjacent to islands is suggested to reduce damage to plant materials.

v. Clustering of New Plant Material. Clustering of new plant material within surface parking lots may be approved if the objectives of this section are met.

10. Landscape Grading Standards.

a. Slopes in Planting Areas. Graded slopes in planting areas should not exceed a 3(Horizontal): 1(Vertical) slope, in order to decrease erosion potential and to facilitate maintenance. Graded slopes planted with grass should not exceed a 4(H): 1(V) slope.

b. Erosion Control. On ungraded slopes equal to or greater than 2(H): 1(V), erosion control netting or alternative procedures shall be used to prevent erosion.

c. Guidelines. The obligation to install plants, shrubs and ground cover includes the obligation to utilize soil, planting practices and irrigation equipment that maximize the likelihood of their long-term survival.

11. General Planting, Irrigation and Maintenance Standards. The following standards apply to the planting requirements set forth above:

a. Coverage. Planting areas should be completely covered with trees, shrubs, flowers, mulched areas, and/or ground covers.

b. Berms and Landforms. Earth berms and landforms in combination with shrubs and trees may be used to achieve the initial planting height requirement.

c. Minimum Width. All planting areas should be a minimum of five feet in width. Planting areas should be wider wherever possible.

d. Sight Clearance. At intersections, plantings shall not create sight obstructions that may compromise pedestrian or traffic safety.

e. Planting Coverage. All required planting areas should extend to the ditch slope, curb line, street edge, or area of sidewalk.

f. Curbs Required. Permanent curbs or structural barriers/dividers should enclose planting areas in vehicle use areas except when draining runoff from pavement to planting areas functioning as rain gardens or other low impact development facilities. Wheel stops should also be used to protect planting areas from damage due to cars overhanging the curb.

g. Plantings Near Utilities. Trees shall not be planted within eight feet of a water or sewer pipeline. Shrubs shall be at least four feet from hydrants. A full screen will be required to screen above-ground utilities from adjacent uses and public rights-of-way. Perimeter plantings shall be clustered in areas to screen structures, utility structures, loading areas, trash enclosures, storage areas and mechanical equipment. This subsection shall not apply to utilities, structures, loading areas, enclosures or equipment unless the utility, structure, loading area, enclosure or equipment is being added as part of the regulated improvement being reviewed.

h. Drainage. Planting areas shall be provided with adequate drainage.

i. Maintenance Requirements. All required landscaping shall be maintained in good condition. Plant material should be cared for in a way that allows their natural form to be maintained, even when the plant reaches maturity. Performance guarantees to ensure maintenance or required landscaping may be required pursuant to MICC 19.01.060. (Ord. 14C-06 § 6; Ord. 10C-06 § 4; Ord. 09C-17 § 6; Ord. 04C-08 § 1).

19.12.050 Vehicular and pedestrian circulation.

A. Objectives.

1. To create an attractive street edge and unified streetscape, to encourage pedestrian activity in commercial areas, stimulate business, maintain adequate public safety, and create a sense of community.

2. To provide for safe and efficient parking and loading areas while minimizing their visual and noise impacts.

3. To provide safe and efficient pedestrian connections within and between projects and the public way to enhance safety and circulation.

B. Standards.

1. Vehicular Circulation Characteristics.

a. Parking Lot Design. Parking areas should be designed for efficient and safe ingress and egress by vehicles and should not inhibit safe pedestrian movement or circulation. Parking lot design should be subordinate to the overall site design and should be located behind new buildings when appropriate and physically feasible. Below grade parking is also encouraged. Planting strips should be incorporated between parking aisles in new and expanded parking lots where space permits. Parking lot development standards, such as stall and aisle dimensions, are contained in Appendix A.

b. Loading Docks. Proposed development of features such as loading docks, and other features designed to support activities with a substantial likelihood of generating significant noise should be designed with noise attenuation walls and sited in a manner to limit impacts to adjacent properties and pedestrian areas.

2. Pedestrian Circulation Characteristics.

a. Pedestrian Improvements. All developments shall provide for pedestrian access including pedestrian walkways, sidewalks, and/or paths. Areas for sitting and gathering should be provided as an integral part of regulated public facilities, regulated residential and commercial building design. Pedestrian improvements should be separated from vehicular areas by physical barriers such as curbs or landscaping. This requirement for new parking lots with fewer than 20 spaces and for additions or remodels may be waived or modified where the applicant can demonstrate that these standards would reduce the amount of parking below what would be required for the site.

b. On-Site Circulation for Regulated Public Facilities and Commercial Buildings. Proposed development should be linked to existing and planned walkways and trails. Entrances of all buildings should be linked to each other and to public ways and parking lots. Where possible and feasible, the pedestrian system shall connect to paths or sidewalks on neighboring properties. (Ord. 04C-08 § 1).

19.12.060 Screening of service and mechanical areas.

A. Objectives.

1. To ensure that building and site appurtenances are properly integrated into the design concept.

2. To properly screen mechanical equipment to reduce visual impacts.

3. To ensure service and truck loading areas, utility structures, and elevators are screened from public view in such a manner that they are not visible from public ways or residential areas.

B. Standards.

1. Accessory Buildings. Ground level outdoor storage buildings, mechanical equipment and utility vaults shall be screened from adjacent public ways.

2. Rooftop Mechanical Equipment and Appurtenances. All rooftop mechanical equipment shall not be visible and shall be enclosed, hidden or screened from adjacent properties, public ways and parks. Rooftop appurtenances are allowed if there is a functional need for the appurtenance and that functional need cannot be met with an appurtenance of a lesser height. This provision shall not be construed to allow building height in excess of the maximum limit. Rooftop appurtenances should be located at least 10 feet from the exterior edge of any building, and shall not cover more than 20 percent of the rooftop area. Appurtenances shall not be located on the roof of a structure unless they are hidden or camouflaged by building elements that were designed for that purpose as an integral part of the building design. All appurtenances located on the roof should be grouped together and incorporated into the roof design and thoroughly screened. The screening should be sight-obscuring, located at least 10 feet from the exterior edge of any building; and effective in obscuring the view of the appurtenances from public streets or sidewalks or residential areas surrounding the building.

3. Meters and Mechanical Units. Water meters, gas meters, electric meters, ground-mounted mechanical units and any other similar structures should be hidden from public view or screened.

4. On-Site Service Areas. All on-site service areas, loading zones, outdoor storage areas, garbage collection and recycling areas and similar activities should be located in an area not visible from public ways. Service areas should accommodate loading, trash bins, recycling facilities, storage areas, utility cabinets, utility meters, transformers, etc. Service areas should be located and designed for easy access by service vehicles and for convenient access by all tenants. Loading activities should generally be concentrated and located where they will not create a nuisance for adjacent uses. Loading docks shall meet the standards identified in MICC 19.12.050(B)(1)(b).

5. Garbage, Recycling Collection and Utility Areas. Garbage, recycling collection and utility areas shall be enclosed and screened around their perimeter by a wall or fence at least seven feet high, concealed on the top and must have self-closing doors. If the area is adjacent to a public way or pedestrian alley, a landscaped planting strip, minimum three feet wide, shall be located on three sides of such facility.

6. Fence, Trellis and Arbor Standards. Fences, trelliswork and arbors shall meet the standards identified in MICC 19.12.040(B)(3).

7. Noise, Vapor, Heat or Fumes. With respect to all aspects of the development referred to above in this section, emissions of noise, vapor, heat or fumes should be mitigated. (Ord. 08C-01 § 7; Ord. 04C-08 § 1).

19.12.070 Lighting.

A. Objectives.

1. To regulate exterior lighting in order to avoid unsafe and unpleasant conditions as the result of poorly designed or installed exterior lighting.

2. To discourage excessive lighting that negatively impacts adjacent land uses.

3. To protect low and moderate density residential zones from the negative impacts associated with institutional, mixed-use, and commercial exterior lighting.

4. To create a safe environment during hours of darkness.

5. To ensure lighting is an integral part of any new or existing development. Lighting shall contribute to the individuality, security and safety of the site design without having overpowering effects on the adjacent areas.

6. To ensure lighting is viewed as an important feature for functional and security purposes and that the design of light fixtures and their structural support is integrated with the architectural theme and style of the main structures on the site.

B. Standards.

1. Architectural Elements. Lighting should be designed as an integral architectural element of the building and site.

2. Function and Security. On-site lighting shall be sufficient for pedestrian, bicyclist, and vehicular safety. Building entrances should be well lit to provide inviting access and safety. Building-mounted lights and window lights should contribute to lighting of walkways in pedestrian areas.

3. Lighting Height. Freestanding, parking area, and building-mounted light fixtures shall not exceed 16 feet in height, including any standard or base.

4. Shielding. All exterior lighting fixtures shall be shielded or located to confine light spread within the site boundaries. Full cut-off fixtures should be used. The use of unshielded incandescent lighting fixtures less than 160 watts and any unshielded lighting less than 50 watts may be allowed. Parking area light fixtures shall be designed to confine emitted light to the parking area.

5. Uplighting of Structures and Signs.

a. Residential Zones. Structures in residential zones shall not be illuminated by uplighting. Limited uplighting of signs and plantings in residential zones may be approved provided there is no glare or spillover lighting off the site boundaries.

b. Nonresidential Zones. Structures, signs, and plantings in nonresidential zones may be illuminated by uplighting, provided there is no glare or spillover lighting off the site boundaries.

6. Light Type. Lighting should use low wattage color-corrected sodium light sources, which give more “natural” light. Metal halide, quartz, neon and mercury vapor lighting are prohibited in residential zones. High pressure sodium lights may only be used as street lights and must be fully shielded. (Ord. 04C-08 § 1).

19.12.080 Signs.

A. Objectives.

1. Signs shall be distinctive in shape, of high quality and durable materials, designed to enhance the architectural character of the building and use the minimum wattage necessary to identify the facility or establishment. Channel or punch-through letters are preferred over a sign that contains the text and/or logo symbols within a single, enclosed cabinet.

2. Signs shall be designed for the purpose of identifying the facility or establishment in an attractive and functional manner and to help customers find the specific establishment and location; signs in residential zones should not serve as general advertising.

3. The size of signs shall be proportional to the size of the building and site.

4. Signs shall be integrated into both the site design and building design, shall be compatible with their residential, office, or business, or public park or open space surroundings, and clearly inform viewers of building or activity use, but shall not detract from the architectural quality of individual buildings or park surroundings.

B. Standards.

1. Freestanding Ground Signs Outside Residential Zones.

a. Number. An individual building or a building complex outside residential zones may display one ground sign on each street frontage.

b. Design. The sign shall be architecturally compatible with the style, materials, colors and details of the building or complex. Use of symbols is encouraged.

c. Size. All signs shall be:

i. Proportionate. Proportionate to the street frontage of the use they identify; and

ii. Maximum Size. In no case shall a freestanding ground sign be larger than:

(A) Twenty-Five Square Feet. Twenty-five square feet for single-tenant building ground signs and complex identification ground signs. Such signs may be allowed in front or side yard setbacks; or

(B) Forty Square Feet. Forty square feet for joint tenant ground signs (identifying more than one facility or establishment within a building or building complex) with six square feet maximum for any one establishment included in a building or building complex; provided, joint tenant ground signs shall be restricted to a maximum of 25 square feet if located within front or side yard setbacks.

d. Maximum Height. The maximum height of any sign within 10 feet from any property line facing a street shall be 42 inches. All other ground signs shall be no higher than six feet.

e. Backs of Signs. Exposed areas of backs of signs should be finished with appropriate color, material or texture to present an attractive appearance relative to the building material, color and texture.

2. Wall Signs Outside Residential Zones.

a. Number and Eligibility. An individual building or a building complex outside residential zones may display one wall sign on each street frontage. A business or other use occupying a building whose only entrance is from a driveway or parking lot shall be allowed one wall sign facing that driveway or parking lot.

b. Size. All signs shall be:

i. Proportionate. Proportionate to the street frontage of the use they identify; and

ii. Maximum Size. In no case shall a wall sign be larger than:

(A) Twenty-Five Square Feet. Twenty-five square feet for any individual business or other use; or

(B) Forty Square Feet. Forty square feet for joint tenant directory signs identifying the occupants of a building or a building complex and located next to the entrance.

c. Determination of Size. The sign size shall be measured as follows:

i. Boxed Sign Displays: Total area of a boxed sign display, including the background and borders.

ii. Individual Letters and Symbols: Total combined area of a rectangle drawn around the outer perimeter of each word and each symbol.

d. Placement. Wall signs may not extend above the building parapet, soffit, the eave line or the roof of the building, or the windowsill of the second story. Wall signs shall be integrated with the overall building and site design.

e. Master Signage Plan. When multiple signs for individual businesses in one building or multiple buildings in a complex are contemplated, a master signage plan stipulating the location and size of allowed signs shall be required.

3. Signs for Non-Single-Family-Dwelling Uses in Residential Zones. One wall sign and one freestanding ground sign are permitted on each separate public street frontage for non-single-family-dwelling uses in residential zones, such as apartment buildings, hospitals, assisted living and retirement facilities, churches, clubs, public facilities, schools, day cares, pre-schools, park and recreation facilities, assembly halls, libraries, pools or stadiums. A wall sign may be unlighted or exterior lighted, not to exceed 12 square feet. A free-standing ground sign shall be no larger than 18 square feet and shall not exceed a maximum height of 42 inches above grade. The location of any freestanding ground sign shall be subject to all setback requirements for the zone in which the sign is located.

4. Signs for Licensed Practitioners or Service Operators in Residential Zones. Licensed practitioners or service operators in residential zones shall be permitted one unlighted window or wall sign for identification purposes only, bearing only the occupant’s name and occupation, not to exceed 72 square inches.

5. Parking Lot Signs. Signs within parking lots should be limited to those necessary for safety and identification. Any required signs for individual stalls should be marked on the pavement. Freestanding or wall-mounted signs should not be permitted, with the exception of ADA handicapped accessible parking signs.

6. Directional Signs.

a. Minimal Number. To address safety concerns and avoid a cluttered appearance, only those directional signs necessary to protect the safety of pedestrians and vehicle occupants shall be allowed.

b. Size and Height. Directional signs shall be no larger than three square feet and no higher than 36 inches above grade.

7. Temporary Signs. Unless prohibited by this chapter, use of temporary signs shall be governed by MICC 19.06.020, Temporary Signs.

8. Street Numbers.

a. Use. City-assigned street numbers should be installed on all buildings.

b. Effect on Permitted Sign Area. Street numbers will not be counted towards permitted sign area.

c. Size. Street numbers for any building or building complex shall be no smaller than six inches in height.

9. Prohibited Signs.

a. Roof. Signs mounted on the roof are prohibited.

b. Projecting Signs. Projecting signs are prohibited in all zones other than the PBZ. Within the PBZ, projecting signs are permitted subject to the Town Center standards set forth in MICC 19.11.140(B)(3)(b).

c. Window Signs. Window signs are prohibited in all zones other than the PBZ, except as provided above in MICC 19.12.080(B)(4). Within the PBZ, window signs are permitted subject to the Town Center standards set forth in MICC 19.11.140(B)(4).

d. Inflated Signs. Inflated signs, balloons and figures are prohibited.

e. Internally Lit Signs. Internally lit signs are prohibited in all zones other than the PBZ. Within the PBZ, lighted signs are permitted subject to the Town Center standards set forth in MICC 19.11.140(B)(9).

f. Neon. Neon signs are prohibited.

g. Portable. Portable signs, such as signs on trailers, are prohibited. This standard is not intended to prohibit A-frame signs as allowed pursuant to MICC 19.06.020, Temporary Signs.

h. Flashing, Moving or Animated Signs, Etc. Flashing, moving, animated, blinking, reflecting, revolving, or other similar signs or signs that incorporate these elements are prohibited.

i. Off-Premises Signs. Off-premises signs (signs related to a building, business, tenant or establishment not located on the same premises as the sign) are prohibited.

j. Vehicles. Signs attached to or painted on vehicles parked and visible from the public right-of-way are prohibited if, based on the relative amount of time the vehicle is parked rather than being used as a means for actual transportation, the vehicle’s primary purpose is as a stationary sign rather than a means for actual transportation.

k. Vending Machines. Vending machines, such as soft drink or snack machines, shall not be placed where they are visible from the public right-of-way.

10. Signs for Public Schools in Public Institution Zones. One wall sign and one freestanding ground sign are permitted for each public school. A wall sign shall not exceed 12 square feet. A freestanding ground sign shall not exceed 18 square feet and shall not exceed a maximum height of 42 inches above grade. A freestanding ground sign shall be set back a minimum of 10 feet from a public right-of-way and 35 feet from abutting properties. Wall and freestanding ground signs shall not have internal lighting, except for an electronic readerboard.

11. Electronic Readerboards. A public school may have no more than one electronic readerboard. This electronic readerboard shall count as the wall sign or freestanding ground sign allowed by MICC 19.12.080(B)(10). Electronic readerboards shall comply with the following:

a. Electronic readerboards shall be designed and placed to minimize light and glare from being visible to adjacent residential properties.

b. Electronic readerboards shall dim during twilight and night hours to reduce glare.

c. Electronic readerboards shall be turned off between 10 pm and 7 am.

d. The display shall include only static text and/or static graphics. No moving graphics, animations such as flying or fading, video, or blinking/pulsing/strobe effects are allowed.

e. Each message and/or graphic shall be displayed for at least 10 seconds. The change from one message/graphic to the next may utilize a scrolling or wipe effect, but the effect shall take no more than one second to complete.

f. Electronic readerboards shall display any message deemed necessary by the City of Mercer Island Emergency Operations Center (EOC) upon request by the EOC. The display of any such message shall be exempt from the requirements of subsections (B)(11)(c) and (B)(11)(e) of this section. (Ord. 14C-06 § 7; Ord. 04C-08 § 1).