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Item 5D - Downtown Urban Design Guidelines - attachment ADOWNTOWN URBAN DESIGN GUIDELINES City of Boulder Boulder, Colorado feBruary 2016 INTRODUCTIONDowntown Urban Design gUiDelines2INTRODUCTIONIntroduction 3 Section 1: The Historic District 10 1.1 General guidelines for the Historic District 14 1.2 Guidelines for the preservation and restoration of local landmarks and contributing buildings 16 1.3 Guidelines for contemporary alterations and additions to local landmarks and contributing buildings 17 1.4 Guidelines for new construction and remodeling non-contributing buildings in the Downtown Historic District 20 Section 2: The Non-Historic & Interface Areas 24 2.1 General guidelines for the Non-Historic & Interface Areas 26 2.2 Commercial buildings in the Non-Historic & Interface Areas 29 2.3 Residential buildings in the Non-Historic & Interface Areas 32 Section 3: The Public Realm 36 3.1 Signs 39 3.2 The Streetscape 40 3.3 Landscaping 44 3.4 Street Furnishings 48 3.5 Historic Features 48 3.6 Public Art 48 Acknowledgements This third edition of the Downtown Urban Design Guidelines is the result of recommendations from a 2015 joint-board working group consisting of representatives from the Landmarks Board, Design Advisory Board, Downtown Management Commission, the Planning Board and City staff. Much of the basis of this document may be attributed to earlier work by the Downtown Alliance, a group of city boards and commissions, non-profit organizations and neighborhood groups including the city of Boulder Planning Board; the Landmarks Board; the Design Advisory Board; the Downtown Management Commission; Downtown Boulder, Inc.; Historic Boulder; and representatives from the Whittier, Mapleton Hill, Goss Grove, and Flatirons neighborhoods. Photo Credits: Cover photo courtesy of Downtown Boulder, Inc. (DBI) Table of ConTenTs Downtown Urban Design gUiDelines 3 What is the purpose of the guidelines? The purpose of this third edition of the Downtown Urban Design Guidelines is to provide a basis for understanding, discussing, and assessing the design quality of proposed preservation, renovation and new construction projects located within the boundaries of the Downtown Historic District, the Non-Historic Area, and the Interface Area. Through the use of these guidelines, it is anticipated both private and public projects will endeavor to preserve and enhance the unique form, scale, and visual character of Downtown while strengthening the identity of the area through encouraging new, compatible development. How are the guidelines organized? The guidelines are organized into three sections. The first two sections address specific geographic areas of the Downtown: the Downtown Historic District and the Non-Historic & Neighborhood Interface Areas. The last section addresses the Public Realm. The sections are organized around several principal guidelines and a number of “follow-up” guidelines. Within the margins are excerpts marked “Note:” and “Code:” reserved for more in depth references to the subject matter. How are the guidelines revised? The guidelines are part of a Downtown Area Plan and are adopted by Planning Board and City Council with advice from the Design Advisory Board. The Landmarks Board approves guidelines for the Downtown Historic District. How are the guidelines administered? Three review bodies are primarily responsible for administering these guidelines: the Landmarks Board (LB), the Design Advisory Board (DAB), and the Downtown Management Commission (DMC). Specifically, the LB reviews all projects located in the Downtown Historic District and landmarked properties located outside of the District but within the downtown boundaries. The Planning Board applies these guidelines as part of the site review process. DAB reviews all projects with a construction value over $25,000 in the Non-Historic and Interface Areas, and the DMC reviews projects located on the Downtown Boulder Mall. When this document uses terms such as "encouragement" and "generally", it acknowledges that these guidelines are utilized in a mandatory review and voluntary context; however, in the review of Landmark Alteration Certificates and Site Review applications, the guidelines may be applied with mandatory effect in the analysis of specific review criteria. Note: The design guidelines include photographs and diagrams to illustrate acceptable or unacceptable approaches. These photographs and diagrams are provided as examples and are not intended to indicate the only options. Note: In general, these guidelines adhere to Local, State and Federal regulations, but wherever a discrepancy may arise, the higher standard shall be applied. Downtown Urban Design gUiDelines4INTRODUCTIONDowntown Boulder is characterized by the eclectic, fine grained and compact urban character of the Downtown Historic District nestled in against the natural backdrop of the Rocky Mountains. These qualities are reflected in the traditional buildings associated with the original settlement of the area, the street grid and bustling economy, and civic life of downtown. This is also where the historic fabric is the setting for contemporary, vibrant and active urban life where people are living, working, shopping and recreating in the shadow of a visible history. The urban design quality becomes a vital part of what makes Downtown Boulder a memorable place. These guidelines are intended to encourage the preservation and enhancement of Downtown’s built environment through recognition of design attributes that are intrinsic to its existing character or essential to its ongoing appeal: • Design innovation and excellence in form and visual character that respect and reference historic architectural context; • Careful consideration of the urban and natural interface including views, green spaces, and waterways; • Human-scaled space that results from the designed interplay of enclosing mass, void, and light; • Street-level design oriented toward the pedestrian in motion; and • Sustainable design practice with respect to solar access, water, energy and materials. Photo Credits: DBI, Anish Palekar (OSMP), City of Boulder DownTown Vision Fig. 1 Map of Downtown Boulder (City of Boulder) Downtown Urban Design gUiDelines 5 Canyon Blv d Canyon Blvd Walnut St Walnut St Pearl St Spruce St Pine St Pearl St Spruce St Arapahoe Ave Arapahoe Ave BroadwayBroadway13th St13th St14th St15th St16th St17th St18th St18th St19th St11th St9th St9th StBroadwayPearl St Walnut St Spruce St Boulder Cre e k Boul d e r C r e e k Arapahoe A v e Canyon Blv d LEGENDN Downtown Historic District Non-Historic & Interface Area Parks Public Realm Pedestrian Mall Civic Area Downtown Urban Design gUiDelines6INTRODUCTIONNote: Scheduling a design review early is important. In addition, scheduling a design review with the appropriate review body is the responsibility of the property owner, developer or their representative. In general, a meeting should be scheduled before a formal application is made to the city for a building permit or development review. For more information regarding the design review and application procedure please contact (303) 441-1880. Note: When requested LB or DAB may act in an advisory capacity to the other board. Note: For further map data please see the City of Boulder eMapLink. The Landmark Alteration Certificate (LAC) Review Process Landmark Alteration Certificate (LAC) review through the Historic Preservation Program is required for exterior changes to landmarked properties and all properties located within the Downtown Historic District boundaries. The majority of applications are reviewed by the Landmarks Design Review committee (LDRC) that meets each week. Routine changes, such as patios and signage, are reviewed by staff. More complex projects, including demolition or new construction, are reviewed by the Landmarks Board. To find out more or for an application, visit the City of Boulder Historic Preservation website, or call (303) 441-1880. The Design Advisory Board (DAB) Process The Design Advisory Board (DAB) reviews projects valued over $25,000 located in the Non-Historic Area and Interface Area which involve the construction of a new building or exterior work on an existing building. The board provides comments to persons responsible for the design and development, and assures compliance with the most recent Downtown Urban Design Guidelines. DAB also reviews projects that require a discretionary review. To find out more, visit the DAB website, or call (303) 441-1880. The Downtown Management Commission (DMC) Process The DMC manages, controls and supervises the business affairs of the Central Area General Improvement District (CAGID) which includes review of projects which extend into the public right-of-way in the Downtown Boulder Pedestrian Mall. Typical projects reviewed by the DMC include outdoor eating areas, signs, awnings, and other elements. To find out more, visit the DMC website, or call (303) 413-7300. The ReView PRoCess Fig. 2 Application progression for projects within Downtown Boulder (Source: City of Boulder) Downtown Urban Design gUiDelines 7 Sta Review & Approval (may not require a Building Permit) Sta Review & Approval (may not require a Building Permit) Downtown Management Commission Design Advisory Board Downtown Project Application Submittal Design Critique Project scope involves exterior and site feature changes in the Downtown Historic District or to landmarked buildings in the Non-Historic Area and the Neighborhood Interface Area. Project scope involves exterior and site features with a construction value of $25,000, or more, in the Non-Historic Area and/or the Neighborhood Interface Area. Approval/Denial of Revocable ROW Permit Project extends into the public right-of-way on the Downtown Boulder Mall Routine alterations: Patio railings, awnings, signage, etc. Administrative Review More complex alterations Landmark Design Review Commission (LDRC) Landmarks Board > 340 sf new freestanding construction, proposed demolitions or an application referred by the LDRC Proceed with Site Review Process (LUR) or Apply for Building Permit (PMT) Downtown Urban Design gUiDelines8INTRODUCTIONNote: More information, on the history of Boulder, including historic photographs and other relevant background, is available at the Boulder History Museum and the Carnegie Branch Library for Local History . Note: Please see the National Register of Historic Places "Downtown Boulder Historic District" nomination for more specific details regarding the historic context and significance as it relates to the architectural history of the area. Photo Credits: Carnegie Branch Library for Local History, City of Boulder In February of 1859, the Boulder City Town Company was organized to establish a supply center for miners going into the mountains in search of gold and silver in the hope that it would grow to "be an important town." Establishment of the two square mile town site followed the discovery of gold near present day Denver, and a resulting flood of prospectors to the area. One such prospector, George R. Williamson recounted that a straight line was laid out for the main street by driving a stake in the ground at the corner of what is now Broadway and Pearl Streets and "a sighting (was made) across this stick to the black spur on the prairie, known as Valmont Butte" made to establish the alignment of Pearl Street.1 From the beginning Pearl Street has been the nucleus of the community, and its main street. In 1860, the fledgling town was described as containing about sixty log buildings (all with dirt floors), located mainly along Pearl Street. Several years later, upon visiting Boulder the intrepid English visitor described the town as "a hideous collection of frame houses on a burning plain." 2 While growth in Boulder was slow until after the end of the Civil War, business generated from the mining camps, together with Boulder’s selection as the county seat in 1861, the arrival of the railroad in 1873, and establishment of a state university in 1876, provided the foundation for steady growth and the construction of substantial business blocks in the commercial center of the town. Businesses were established along Pearl Street and adjoining streets to supply the needs of the town, local farmers, and mining camps. By the 1880s, the commercial area had developed into bustling hub of restaurants, groceries, saloons, liquor stores, liveries, lumber yards, drug stores, dry goods stores, hardware stores, feed and flour stores, barbers, paint shops, and tailors, in addition to fraternal lodges and the county courthouse. An 1880 account of Boulder in the Boulder County News observed, "I’ve never seen a city of this size with so many saloons (approximately eighteen) and so few drunks."3 Streetcar service enabled residents in new areas of the city to conveniently shop and conduct business downtown as Boulder transformed from a supply town to a sleepy university city with commercial activities centered on and around Pearl Street. The Denver & Interurban Railroad (an intercity connection with Denver) ran along Pearl Street from 1908 until 1917. During the 1920s, several new commercial buildings were erected, updating the appearance of the downtown with Twentieth Century influences. The first decades of the 1900s also saw a rising awareness of Boulder’s potential to draw newcomers and tourists with construction of the Boulderado Hotel in 1909 and the citywide planning for the improvement of Boulder with the Frederick Law Olmsted, Jr. masterplan in 1910. Increasingly, Boulder residents were becoming sensitive to the built and natural environment, leading Saco DeBoer’s 1928 zoning proposal establishing the first zoning ordinance creating seven zoning districts and the first height restrictions limiting downtown buildings to seventy-five feet and neighborhood shopping districts to thirty-five feet. Boulder experienced tremendous growth after World War II as the university grew and the city marketed itself as a perfect place to locate “clean” industry. This led to a number of scientific research institutions and companies locating in the city. The resulting new jobs led to many new residential neighborhoods and automobile-oriented neighborhood shopping areas outside of the core area, creating competition to downtown and leading to the “modernization” of storefronts during the 1950s and 1960s. By the early 1970s, a merchant-led effort to revitalize Pearl Street was underway. Recognizing Boulder’s area growth limitations as a result of acquisition of open space around the city, community leaders joined with downtown property owners and merchants to turn the four blocks of Pearl Street between 11th and 15th Streets into a pedestrian mall. The Pearl Street Mall is among the most successful such pedestrian ways in the United States with many restored historic buildings and a vibrant commercial area. In 1980, the Downtown Historic District was listed in the National Register of Historic Places and in 1999 the area was designated a local historic district. 1 “Boulder in Perspective – From Search for Gold to the Gold of Research”, J.B. Schooland, Johnson Pub., 1980, p.136 2 “ A Lady’s Life in the Rocky Mountains”, Isabella L. Bird, John Murray Pub., 1879, p.230 3 “Boulder in Perspective – From Search for Gold to the Gold of Research”, J.B. Schooland, Johnson Pub., 1980 DownTown hisToRy Downtown Urban Design gUiDelines 9 Fig. 2 Downtown Historic District Map (Source: City of Boulder) Canyon Blv d Canyon Blvd Walnut St Pearl St Spruce St Pine St Pearl St Spruce St Arapahoe Ave Arapahoe Ave BroadwayBroadway13th St13th St14th St15th St16th St17th St18th St18th St19th St11th St9th St9th StBroadwayPearl St Walnut St Spruce St Boulder Cre e k Boul d e r C r e e k Arapahoe A v e Canyon Blv d Chamberlai n H i s t o r i c D i s t r i c t Mapleton Hill Histori c Di s t ri c t LEGENDN Downtown Historic District Mapleton and Chamberlain Historic Districts Parks Pedestrian Mall Individual Landmarks Downtown Urban Design gUiDelines10SECTION 1: THE HISTORIC DISTRICT Section 1 Downtown Urban Design gUiDelines 11 The hisToric DisTricT Note: All buildings in the district have been evaluated for historic significance and are subject to Landmarks Board review when exterior work is involved. Any changes to a building, or site, require a Landmark Alteration Certificate prior to commencement. The boundaries of the Downtown Historic District, designated in 1999 with a period of significance from 1858-1946, generally conform to the boundaries of the Downtown Boulder National Register Historic District. The district contains the City’s greatest concentration of historic commercial buildings, especially along Pearl Street which forms its central spine. These buildings not only serve as a link with our cultural heritage, they also establish a model for design quality. Such buildings are resources for education, recreation and human enjoyment. They provide Downtown with a rich character and a human scale that are unique assets for both residents and visitors. Development in the Downtown Historic District must be especially sensitive to issues of compatibility. The economic success of the area is in many ways dependent on maintaining the historic character and quality that sets the it apart from other shopping areas. For this reason, the preservation, restoration, and appropriate rehabilitation of older buildings in this district is of great importance. The urban design objectives for the Downtown Historic District are to: • Preserve and restore historic buildings. • Preserve the integrity of the historic architectural features of individual buildings. • Ensure that alterations and new construction strengthen and maintain the historic integrity of individual buildings and of the district at large. • Encourage new development that will respect and enhance the visual character. • Preserve the central area as a place for intense pedestrian activity. downtown urBan design guidelines12SECTION 1: THE HISTORIC DISTRICTHistoric properties are organized into three categories: • Local Landmark Buildings - These buildings are officially designated as City of Boulder local landmarks. They have a special character, historic, architectural, or aesthetic interest or value in Boulder’s local history. Landmarked buildings may include contributing properties to the Downtown Historic District. The greatest care must be given to preserving, restoring, and designing additions to these buildings. • Contributing Buildings - Contributing buildings are those built during the district’s period of significance (1858 through 1946) that exist in comparatively “original” condition, or that have been appropriately restored, and that clearly contribute to the historic significance and integrity of the area. Such buildings may have additions that are compatible with the historic character of the original building, have original material now covered, or have experienced some alteration, yet continue to convey some sense of history. Rehabilitations and additions should be sensitive and appropriate to the historic building and district. • Non-Contributing Buildings - There are two types of non-contributing buildings in the Downtown Boulder Historic District. First, buildings built during the district’s period of significance that have been altered to such an extent that historic information is not interpretable and restoration is not possible. Such buildings should be evaluated on a case by case basis to determine if saving and restoring them is feasible or desirable. Second, buildings erected after 1946 which are not individually significant. For alterations to these buildings, the guidelines for new construction and/or remodel of non-contributing buildings in this section apply. Note: The City’s planning department maintains a file of each building in the Downtown area more than 50 years in age. The official Inventory/Survey forms on file indicate the level of significance of each building within the Downtown Historic District. For more information please visit the City of Boulder Historic Preservation website or call (303) 441-1800. Fig. 3 Downtown Historic District Properties (Source: City of Boulder) Pine St BroadwayBroadway13th St14th St15th St16th St11th St9th St Pearl St Walnut St Spruce St Canyon Blv d LEGENDN Landmarked & Contributing Contributing Buildings Downtown Historic District Parks Pedestrian Mall Downtown Urban Design gUiDelines 13 downtown urBan design guidelines14SECTION 1: THE HISTORIC DISTRICTNote: It is neither the intention of this guideline to recreate the past, nor to encourage theme design in the historic district, if the original building facade or original building materials do not exist. However, if documentary evidence exists, such as photographs, then an acceptable alternative is to reconstruct the facade. Note: For further information on recommended treatments for historic properties please see The Secretary of the Interior Standards for the Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating Restoring and Reconstructing Historic Buildings. 1.1 General guidelines for the Historic District The following guidelines apply to all areas of the Downtown Boulder Historic District. A. The use of traditional, durable materials as the primary building material is encouraged to reflect the historic building construction and development pattern within the district. Choose accent materials similar in texture and scale to others in the district. 1. These following materials are generally appropriate: • Full dimension brick and stone masonry • Finish carpentry details, e.g. cornice molding, door and window casing • Finished lumber to achieve traditional patterns, e.g. horizontal siding rather than diagonal • Finished, embossed or painted metal and sheet metal • Clear or lightly tinted glass • Ceramic tiles • Brick, clay and ceramic pavers • Slate, finished metal, glazed ceramic and tile roofs • Brick, concrete or stone lintels • Brick, wood or stone columns 2. The following materials are generally inappropriate: • Thin veneer products • Vinyl replacement windows • EIFS systems or EIFS decorative elements • Faux or simulated materials, including composite wood • Coarsely finished, “rustic” materials, such as wood shakes, shingles, barn board or stained fir plywood • Poorly crafted or “rustic” woodworking and finishing techniques • Indoor-outdoor carpeting or astro-turf • Corrugated metal and fiberglass (unless used sparingly) • Moss rock • “Antique” or old brick with partial paint, mottled light variegated brick, oversized brick and white brick mortar • Ornate wrought-iron, “New Orleans” style grille and rail work • Stucco surfaces that are highly textured such as those sometimes associated with a “hacienda” or “Mediterranean” style • Expanded metal • Silver or clear anodized aluminum sheets • Silver or clear aluminum extrusions for windows and doorways • Residential type sliding glass doors • Imitation wood siding or stone • Flat or molded plastic sheeting in quantities exceeding five square feet when used as primary facade materials • Imitation metal “rock work” • Plastic molded imitations of any conventional building material • Mirror or metalized reflective glass • Glass block B. Awnings may be used to provide visual depth and shade. 1. Awnings should be designed to fit the storefront opening to emphasize the building’s proportions and have at least an downtown urBan design guidelines 15 Note: For detailed information on historic buildings and preservation information on individual building elements see the National Park Service (NPS) Technical Briefs. Code: See the Boulder Revised Code (B.R.C.) Section 9-9-16, “Outdoor Lighting” for lighting requirements. Code: See the B.R.C. Section 9-9-14, "Parking Lot Landscaping Standards" for parking lot screening requirements. eight foot clearance from the sidewalk. Awnings should not obscure or damage important architectural details. 2. Operable fabric awnings are encouraged. Metal awnings or canopies that are similar in form to fabric awnings may be appropriate when designed as an integral part of the building facade, and do not appear as tacked-on additions. Awning color should be coordinated with the color scheme of the entire building front. Mechanized awnings and awnings on the upper stories are discouraged. C. Select building colors appropriate to the area’s historic character. 1. Select a color scheme that will visually link the building to its past as well as to others in the area. Consider colors that are compatible with the building’s predominant materials, or do an analysis of colors pre-existing on the building and use one of the colors found. 2. Develop a comprehensive color scheme. Consider the building as a whole as well as the details that need emphasis. Softer muted colors establish a uniform background. Establish a hierarchy for the color palette with one color on similar elements such as window frames. Reserve brighter colors for small special accents to emphasize entry ways and to highlight special structural ornamentation. 3. It is not appropriate to paint unpainted brick. If the brick is already painted, paint removal is preferred. Avoid paint removal procedures that damage the original brick finish such as sand blasting or caustic chemicals. Before removing paint conduct a test to determine detrimental effects. If the existing paint on the brick is in poor condition and paint removal will damage the underlying brick, the brick should be repainted. D. Minimize the visibility of mechanical, structural, or electrical appurtenances. 1. Use low-profile mechanical units and elevator shafts that are not visible from the street. If this is not possible, set back or screen rooftop equipment from view. Be sensitive to views from the upper floors of neighboring buildings. Skylights or solar panels should have low profiles and not be visible from the public right-of-way. These features should be installed in a manner which minimizes damage to historic materials. E. Improve rear or side alley elevations to enhance public access from parking lots and alleys. 1. Where buildings are built to the alley edge, consider opportunities for alley display windows and secondary customer or employee entries. 2. Screening for service equipment, trash, or any other rear-of-building elements should be designed as an integral part of the overall design. Where intact, historic alley facades should be preserved along with original features and materials. Alterations should be compatible with the historic scale and character of the building and block. F. Exterior building lighting should be designed to enhance the overall architecture of the building. Security lighting should be designed for safety, as well as night-time appearance. G. Reduce the visual impact of structured and surface parking. 1. Parking structures should be compatible with the historic district, overall block and adjacent buildings. All parking structures should be architecturally screened and/or wrapped with an occupiable use. 2. Surface Parking should be located to the rear of the property and screened from view. 3. Pedestrian routes in structures and parking lots should be easily identifiable and accessed, with clear visual connections to the sidewalks and buildings. H. The law requires that universal access be located with the principal public entrance. 1. In existing buildings, where the only route is not accessible from the principal public entrance, a rear or side service entrance route may be considered. 2. Ramps and related accessibility modifications to a historic property should be compatible with the character of the building. 8 1 9 11 7 6 3 10 4 5 2 Fig. 4 Historic Building Elements (Source: City of Boulder) downtown urBan design guidelines16SECTION 1: THE HISTORIC DISTRICTNote: For detailed information the preservation, rehabilitation and restoration of historic buildings and specific building elements see the NPS Technical Briefs. 1.2 Guidelines for the preservation and restoration of local landmarks and contributing buildings While it is acknowledged that changes to structures in the Downtown Historic District will occur over time, it is also a concern that these changes not damage the historic building fabric and character of the area. Preservation of the exteriors and storefronts of these buildings will continue their contribution to the unique historic character of the Downtown. Any building renovation or alteration, no matter the planned use, must retain the overall design integrity of the historic building by protecting the original features and materials and respecting the traditional design elements. The following are the guidelines for the preservation and restoration of local landmarks and contributing buildings: A. Preserve Original Character, Façades and Materials. Wherever possible retain these elements through restoration and repair, rather than replacement. If portions of the original material must be replaced, use a material similar to the original. The following elements are part of the traditional storefront building typology indicative to the development of Downtown Boulder. These elements include: 1. Full-dimension bricks, or stone 2. Display window bulkheads 3. Large storefront display windows 4. Recessed and corner entrances 5. Secondary entrances and detailing 6. Storefront transom 7. Sign bands and storefront cornice 8. Parapet walls, caps, and/or roof cornices 9. Upper story vertically proportioned windows and/or fenestrations 10. Columns, pilasters, and piers 11. Decorative window sills, lintels, window hoods, and other window assembly elements B. Avoid concealing or removing original materials. If the original material has been covered, uncover it if feasible. C. Maintain the historic building set back line. Preserve the historic relationship of the building to the street or property line. Where buildings are built to the alley edge, consider secondary customer entries if original materials and features are not damaged. Fig. 5 A new addition to a historic block with compatible scale (Source: National Park Service) downtown urBan design guidelines 17 Code: See the B.R.C. Section 9-7-1, "Schedule of Form and Bulk Standards" for additional information on height and set back requirements. 1.3 Guidelines for contemporary alterations and additions to local landmarks and contributing buildings The purpose of this section is to provide guidance for the design of additions or alterations to contributing buildings in order to retain the historic character of the overall district. While renovations and building design is expected to reflect the character of its own time acknowledging the Downtown as a living district, it is important that it also respect the traditional qualities that makes the Downtown unique, such as massing, scale, use of storefront detailing, and choice of materials. A. Distinguish additions to historic buildings. 1. Additions to historic buildings should be differentiated, yet compatible, from the original while maintaining visual continuity through the use of design elements such as proportion and scale, siting, facade set back, and materials that are of a similar color and texture. When design elements contrast too strongly with the original structure, the addition will appear visually incompatible. Conversely, when the original design is replicated, the addition is indistinguishable and the historical evolution of the building becomes unrecognizable. New additions should be subordinate to the original building form. 2. For additions to a historic building, retain the original proportions, scale, and character of the main facade. Position the addition so it is subordinate to the original building. Express the difference between the original facade and the addition with a subtle change in color, texture or materials. 3. Maintain the proportions and the established pattern of upper story windows. In addition, upper floors should incorporate traditional vertically proportioned window openings with less window glazing and transparency than the lower floors. Use windows similar in size and shape to those used historically to maintain the facade pattern of the block. 4. Maintain the rhythm established by the repetition of the traditional ~25’ facade widths for projects that extend over several lots by changing the materials, patterns, reveals, and building set backs in uniform intervals or by using design elements such as columns or pilasters. 5. Set back vertical additions to historic buildings maintaining the height of the primary, historic facade. Lateral additions should be subordinate and differentiated from the primary historic building. Additions need to demonstrate a harmonious relationship with the historic building height, mass, and scale. Fig. 6 Historic pattern of building widths along Pearl Street Mall (Source: City of Boulder) Downtown Urban Design gUiDelines18SECTION 1: THE HISTORIC DISTRICT Fig. 8 A non-conforming addition with incompatible materials, massing and window proportioning (Source: National Park Service) Fig. 7 A new addition demonstrating a harmonious use of similar materials in a differentiated, yet compatible manner (Source: Gossens Bachman) Downtown Urban Design gUiDelines 19 downtown urBan design guidelines20SECTION 1: THE HISTORIC DISTRICTCode: Objects or building elements extending into the public right-of-way require a revocable right-of-way permit and/or lease agreement, see the B.R.C Section 8-6-6, "Requirements for Revocable Permits, Short-Term Leases and Long- Term Leases" for more information. 1.4 Guidelines for new construction and remodeling non-contributing buildings in the Downtown Historic District The purpose of this section is to provide guidance for the design of new construction and the renovation of non-contributing buildings in order to retain the historic character of the overall district. While new building design is expected to reflect the character of its own time acknowledging the Downtown as a living district, it is important that it also respect the traditional qualities that makes the Downtown unique, such as massing, scale, use of storefront detailing, and choice of materials. A. Incorporate traditional building elements in new design and construction. Careful integration of traditional facade features reinforces patterns and visual alignments that contribute to the overall character of the district. These features may be interpreted in new and contemporary ways. Please see Section 1.2 for a list of historic building elements. B. Construct new buildings to maintain the continuity of the historic building relationship to the street, adjacent properties, and/ or the block. C. Maintain a human scale rather than a monolithic or monumental scale. Smaller scale buildings and the use of traditionally- sized building components help to establish a human scale and maintain the character of Downtown. Standard size brick, uniform building components, and standard window sizes are most appropriate. D. Consider the proportioning of the height and mass to the building footprint. In general, buildings should appear similar in height, mass, and scale to other buildings in the historic area to maintain the historic district’s visual integrity and unique character. At the same time, it is important to maintain a variety of heights. While the actual heights of buildings are of concern, the perceived heights of buildings are equally important. One, two and three story buildings make up the primary architectural fabric of the Downtown, with taller buildings located at key intersections. 1. Relate the height of buildings to neighboring structures at the sidewalk edge. For new structures that are significantly taller than adjacent buildings, upper floors should be set-back a minimum of 15’ from the front facade to reduce the perceived height. 2. Consider the effect of building height on shading and views. Building height can shade sidewalks during winter months leading to icy sidewalks and unappealing pedestrian areas E. Provide a variation of roof heights and types. F. Buildings are expected to be designed on all exposed elevations. Primary facade materials are to extend to secondary elevations, or wrap building corners, a proportionally relevant distance as to portray a sense of depth. G. Construct residential units to include entry stoops and/or porches. Residential entry porches are encouraged to extend 18” to 30” above grade. Construct commercial buildings at grade. Fig. 9 A compatible renovation with references to adjacent building height and contemporary references to the storefront building typology (Source: Olson Kundig) Downtown Urban Design gUiDelines 21 Fig. 10 New construction with compatible material, scale and window proportioning (Source: City of Boulder) Fig. 11 New construction with contemporary, yet compatible, references to historic building elements (Source: Jorge Mastropietro Architects Atelier) Downtown Urban Design gUiDelines22SECTION 1: THE HISTORIC DISTRICT Fig. 12 New construction with appropriate historic references including materiality and scale (Source: City of Boulder) Downtown Urban Design gUiDelines 23 Fig. 13 Map of the Downtown Historic District, Non-HIstoric and the Interface Area (Source: City of Boulder) Canyon Blv d Canyon Blvd Walnut St Walnut St Pearl St Spruce St Pine St Pearl St Spruce St Arapahoe Ave Arapahoe Ave BroadwayBroadway13th St13th St14th St15th St16th St17th St18th St18th St19th St11th St9th St9th StBroadwayPearl St Walnut St Spruce St Boulder Cre e k Boul d e r C r e e k Arapahoe A v e Canyon Blv d LEGENDN Downtown Historic District Interface Area Parks Non-Historic Area Pedestrian Mall Downtown Urban Design gUiDelines24SECTION 2: THE NON-HISTORIC & INTERFACE AREAS Downtown Urban Design gUiDelines 25 Code: See the B.R.C. Section 9-2-4, "Good Neighbor Meetings and Management Plans" or contact the DMC at (303) 413-7300. Important design elements are 1) the Non-Historic Area’s relationship to its surroundings, including the Historic Area, the Civic Park area, and the residential quality of the Interface Area, 2) the pedestrian quality of the area including the Downtown Boulder pedestrian mall, east and west Pearl Street, Spruce and Walnut streets, Canyon Boulevard. and the north-south streets that connect the Civic Area to the Downtown Boulder pedestrian mall area, and 3) new building design can reflect the character of its own time and meaningful juxtapositions, while respecting the integrity, scale, and massing of historic buildings in the surrounding areas. Creative interpretations of traditional design elements, and designs that reflect the character of their time, are encouraged. The designs should be compatible with the surrounding historic context, but distinguishable. These guidelines also discourage projects that create inhospitable pedestrian design, and buildings that are inappropriate in scale and massing to their surroundings. The Interface Area is composed of the blocks that link the core of the Downtown to the surrounding residential neighborhoods. This area requires special design sensitivities that must be addressed when commercial buildings are located adjacent to residential areas. Impacts to the surrounding residential areas can be minimized through careful design which respects the scale and quality of adjacent residential uses and thoughtfully transitions the commercial and residential areas. The urban design objectives for the Non-Historic and Interface Areas are to: • Reinforce the character of Downtown as a pedestrian place by encouraging architectural solutions that are visually pleasing, reflective of contemporary times yet stylistically appropriate to the context, and compatible in scale and character with their street. • Encourage sensitive design along the edge where the Downtown commercial area abuts residential neighborhoods. • Emphasize a clear distinction between the commercial and residential interface areas. • Maintain the diversity in building type and size, and respect the adjoining residential character. • Discourage adverse impacts from noise, night lighting, poor building design, and commercial service areas on adjacent residential neighborhoods. The non-hisToRiC & inTeRfaCe aReasseCTion 2 Downtown Urban Design gUiDelines26SECTION 2: THE NON-HISTORIC & INTERFACE AREAS2.1 General guidelines for the Non-Historic and Interface Areas A. Maintain the historic or predominant building set back line. 1. Maintain the relationship and continuity of the building wall to the street or property line. 2. For commercial uses in residential buildings, maintain the predominant residential set back of the block, including any porches. B. Minimize the visibility of mechanical, structural, or electrical appurtenances 1. Use low-profile mechanical units and elevator shafts that are not visible from the street. If this is not possible, set back or screen rooftop equipment from view. Be sensitive to views from the upper floors of neighboring buildings. Skylights or solar panels should have low profiles and not be visible from the public right-of-way. C. Design all sides of the building including alley elevations. 1. Well designed rear building entrances, windows, balconies, and planting areas are encouraged. 2. Improve rear or side alley elevations to enhance public access from parking lots and alleys. 3. Where buildings are built to the alley edge, consider opportunities for alley display windows and secondary customer or employee entries. 4. Primary facade materials are to extend to secondary elevations, or wrap building corners, a sufficient amount as to portray a sense of depth. 5. Screening for service equipment, trash, or any other rear-of-building elements should be designed as an integral part of the overall design. Where intact, historic alley facades should be preserved along with original features and materials. D. Exterior building lighting should be designed to enhance the overall architecture of the building. Security lighting should be designed for safety, as well as night-time appearance. E. Reduce the visual impact of structured and surface parking. 1. Parking structures should be compatible to the historic district and adjacent buildings. All parking structures should be architecturally screened and/or wrapped with an occupiable use. 2. Locate any surface parking to the rear of the property. All surface parking must be screened. 3. Pedestrian routes in structures and parking lots should be easily identifiable and accessed, with clear visual connections to the sidewalks and buildings. F. The law requires that universal access be located with the principal public entrance. G. Consider the quality of open space incorporated into new and renovated buildings. When appropriate to the context, integrate the surrounding open spaces into the building design. Well programmed plazas, courtyards, outdoor seating and dining areas on or adjacent to open spaces and pedestrian routes are encouraged. Note: See Section 3 for encroachments into the public right-of-way discussion on revocable lease and allowable dimensions. Code: See the B.R.C. Section 9-9-14, "Parking Lot Landscaping Standards" for parking lot screening requirements. Code: See the B.R.C. Section 9-9-16, “Outdoor Lighting” for lighting requirements. Note: A goal of the city is to make the Downtown as accessible as possible. All accessible design elements must conform to all applicable Federal, State and Local laws and codes. Wherever a discrepancy may arise, the higher standard shall be applied. Downtown Urban Design gUiDelines 27 Fig. 14 A contemporary infill development with appropriate materiality, massing, and human scale elements (Source: Beyer Blinder Belle) Fig. 15 A contemporary infill development with traditional materials, an innovative approach to historic window proportioning and recessed upper floor (Source: Jorge Mastropietro Architects Atelier) Fig. 16 A contemporary infill development with alternative material choices and a traditional storefront building form (Source: City of Boulder) Downtown Urban Design gUiDelines28SECTION 2: THE NON-HISTORIC & INTERFACE AREAS Downtown Urban Design gUiDelines 29 Code: See the B.R.C. Section 9-7-1, "Schedule of Form and Bulk Standards" for specific height and set back requirements. 2.2 Commercial buildings in the Non-Historic and Interface Areas A. Consider incorporating traditional facade elements in new and contemporary ways. See Section 1: The Downtown Historic District for specific building elements. B. Consider the height, mass, and scale of buildings. 1. In general, buildings should appear similar in height, mass, and scale to other buildings in the area. At the same time, it is important to maintain a variety of heights. While the actual heights of buildings are of concern, the perceived heights of buildings are equally important. One, two and three story buildings make up the primary architectural fabric of the Downtown, with taller buildings located at key intersections. 2. Consider the height and proportion of buildings to neighboring structures. For new structures that are significantly taller than adjacent buildings, upper floors should be set-back a minimum of 15 feet from the front facade to reduce the perceived height. 3. Consider the effect of building height on shading and views. Building height can shade sidewalks during winter months leading to icy sidewalks and unappealing pedestrian areas. 4. Maintain the traditional, established breaks between buildings, such as existing paseos. 5. For projects located in the Interface Area, construct buildings three floors or less and consider the adjacent residential height, mass, and scale. 6. Commercial construction on a primarily residential block should be designed to reflect a residential character, e.g. residential set back on a primarily residential street. C. Maintain a human scale, rather than monolithic or monumental scale. 1. Avoid large featureless facade surfaces. Include architectural elements and patterns that divide the facade into familiar intervals. A single facade should not exceed a maximum of 75 linear feet. 2. Consider how the texture and pattern of building materials will be perceived. Use traditionally sized building components in a way that incorporates details, textures, and patterns to establish a sense of human scale. 3. Maintain the distinction between ground and upper floors. Develop the first floor facade as primarily transparent. Consider using windows and other architectural features to create a pattern that will reinforce the traditional facade rhythm found on commercial buildings in the Downtown area. Lower floors are generally differentiated by a higher percentage of glazing and transparency than upper floors. D. Construct primary entrances at grade. Fig. 17 An adaptive reuse building with a contemporary interpretation of materials (Source: McHenry Architecture/Photographer: David J. Murray) Downtown Urban Design gUiDelines30SECTION 2: THE NON-HISTORIC & INTERFACE AREAS Fig. 18 An appropriate adaptive reuse of an existing residential building into a commercial occupancy (Source: City of Boulder) Downtown Urban Design gUiDelines 31 Fig. 19 A contemporary commercial building with traditional storefront proportioning including delineating the bottom, middle and top sections (Source: City of Boulder) Downtown Urban Design gUiDelines32SECTION 2: THE NON-HISTORIC & INTERFACE AREAS 2.3 Residential buildings in the Non-Historic and Interface Areas A. Maintain the diverse architectural character of the residential buildings in the Interface Area. B. Construct residential units to include entry stoops and/or porches. Residential entry porches are encouraged to extend 18” to 30” above grade. C. When feasible, maintain residential uses in historic residential buildings. Fig. 20 A well-articulated alley elevation with an appropriately screened trash enclosure (Source: City of Boulder) Fig. 21 A contemporary row house with compatible materials and overall form (Source: City of Boulder) Downtown Urban Design gUiDelines 33 Fig. 22 A contemporary multifamily residential development with compatible materials and vertically oriented exterior detailing reflecting a townhome or rowhome building type (Source: Studio Architects) Downtown Urban Design gUiDelines34SECTION 2: THE NON-HISTORIC & INTERFACE AREAS Fig. 23 Contemporary single family residence in a historic district with compatible materials, scale and overall references to the surrounding vernacular roof forms (Source: Jeff Jordan Architects) Downtown Urban Design gUiDelines 35 Fig. 23 The Downtown Pedestrian Mall (Source: City of Boulder) Downtown Urban Design gUiDelines36SECTION 3: THE PUBLIC REALM Downtown Urban Design gUiDelines 37 The term “public realm” refers to the entire system of open space, landscaping, signage, streets and sidewalks, by which people circulate through and experience the Downtown. Our image of Downtown Boulder, and the ease and safety with which we move through it, is determined by the quality of the streetscape. The urban design objectives of the Public Realm Guideline are to: • Unify the visual image of Downtown by creating a series of public sitting areas, completing the rhythm of street trees and street lighting, and providing landscaping with seasonal color or other qualities of visual interest. • Create a pedestrian-oriented environment that is safe, accessible, visually pleasing, and comfortable. • Strengthen Downtown’s visual connections. Visually and functionally connect the Downtown Boulder pedestrian mall and Civic Park, or east and west Pearl Street to the Downtown Boulder pedestrian mall. • Maintain the visual unity and historic character of the Downtown Boulder pedestrian mall through the use of traditional materials. • Respect and preserve adjacent residential neighborhoods through the use of residentially appropriate streetscape design. • Encourage design and sign placement that promotes Downtown businesses while complementing the character and scale of the building. • Promote signs that are designed as an integral yet noticeable part of a building’s overall design. • Promote the sign design and placement that is effective individually and harmonious with the overall signage of the block. • Encourage comfortable spaces by integrating appropriate landscaping and street trees into the public realm. • Create an overall image in which a building, signage, and site design relate to each other. The PubliC RealmseCTion 3 Fig. 24 Downtown wall sign with directional lighting (Source: City of Boulder) Fig. 25 Awning signs and patio extension (Source: City of Boulder) Fig. 26 Projecting sign (Source: City of Boulder) Downtown Urban Design gUiDelines38SECTION 3: THE PUBLIC REALM Downtown Urban Design gUiDelines 39 3.1 Signs A. Commercial signs should function to identify and locate businesses, promote commercial activity, attract customers, provide direction and information, and in some cases create visual delight and architectural interest. B. Following are principal sign types that are applicable in the Downtown: 1. Wall Signs: Wall signs are limited in size and defined as projecting less than 15 inches from the building. Wall signs should be positioned within architectural features such as the panels above storefronts, sign bands, on the transom windows, or flanking doorways. Wall mounted signs should align with others on a block to maintain established patterns. 2. Projecting Signs: Projecting signs should be positioned along the first floor level of the facade. Projecting signs may take on their own special shape, or create their own symbol within the overall facade design. 3. Awning Signs: Awnings should be positioned to emphasize special shapes or details of the facade, to draw attention to the shop entrances or to emphasize a display window. Awning signs may be illustrated with letters or symbols. C. Signage should be designed as an integral part of the overall building design. In general, signs should not obscure important architectural details. When several businesses share a building, signs should be aligned or organized in a directory. D. Use simple signs to clearly convey their messages. 1. Sign materials should be durable and easy to maintain. Appropriate sign materials include painted or carved wood, carved wooden letters, epoxy letters, galvanized sheet metal, stone, specialty or decorative glass, clear and colored acrylic, or neon. 2. Lighting external to the sign surface with illumination directed toward the sign is preferred. External lighting may also highlight architectural features. Internally lit signs are generally discouraged. The light level should not overpower the facade or other signs on the street. The light source should be shielded from pedestrian view. The lighting of symbol signs is encouraged. Internal lighting may be appropriate where only letters are illuminated or neon is used. Neon is acceptable, though restricted in size, if it does not obscure architectural detail or overly illuminate display windows. 3. Signs should be designed in simple, straight-forward shapes that convey their message clearly. Symbols are easily read and enhance the pedestrian quality of the Downtown. 4. Lettering styles should be proportioned, simple, and easy to read. In most instances, a simple typeface is preferred over a faddish or overly ornate type style. The number of type styles should be limited to two per sign. As a general rule, the letter forms should occupy not more than 75% of the total sign panel. Code: Awnings, signage, patio extensions, and other associated structures or objects extending into the public right-of- way require a revocable right-of-way permit and/or lease agreement, see the B.R.C Section 8-6-6, "Requirements for Revocable Permits, Short-Term Leases and Long-Term Leases" for more information. Note: The following is meant as a supplement to the city’s Sign Code. Sign permits, obtained through the Planning Department, are required. Signs that extend into the Downtown Boulder pedestrian mall will require review by the Downtown Management Commission. For further information call the DMC at (303) 413-7300 and the Planning Department at (303) 441-1880. Code: Signs on historic buildings or in historic districts must comply with the B.R.C. Chapter 9-11 “Historic Preservation” and Section 9-9-21, "Signs" provisions. Downtown Urban Design gUiDelines40SECTION 3: THE PUBLIC REALM3.2 The Streetscape A. The existing street hierarchy is the basis for designing the streetscape. The concept of a street hierarchy is based on understanding how various Downtown streets function. For example, Canyon Boulevard and Broadway are major vehicular streets, thus street improvements should provide for large volumes of traffic while buffering pedestrians from traffic impacts. Four types of streets have been identified: 1. The Downtown Boulder pedestrian mall (a vehicle-free pedestrian street): The Downtown Boulder pedestrian mall, which encompasses Pearl Street from 11th to 15th Streets, is the most intensely used pedestrian zone in the area. As a shopping, festival, and public gathering place it will remain a vehicle free area with a unified brick paving design. Elaborate landscape treatments, including seasonally-varied plantings and coordinated street furniture, add to the pedestrian ambiance. 2. Canyon Boulevard and Broadway (major vehicular through streets): Canyon Boulevard and Broadway accommodate large volumes of traffic moving through the Downtown. Streetscape features should be designed to buffer pedestrians from traffic impacts, provide greater building set backs and detached sidewalks with planting strips between the sidewalk and curb. The exception is the section of Broadway between Canyon Boulevard and Spruce Street in which attached sidewalks are needed to accommodate more intense pedestrian use. In areas with detached sidewalks, well designed landscaping and street trees shall be provided. On Canyon Boulevard, the use of landscaped median strips and pedestrian safe zones should be designed to minimize pedestrian/vehicular conflicts. 3. 9th, 10th, 11th, 13th, and 14th Streets (north/south pedestrian connectors): These five north/south streets provide the main pedestrian connections between the Downtown Boulder pedestrian mall and the Civic Park. Where these streets cross Canyon Boulevard, which is very wide, crosswalk designs that visually link the north and south sides of the boulevard are important. The use of similar materials, intersection gateway features, landscaping, and street furniture will help to visually weave the areas together and promote pedestrian access between these two important Downtown public gathering places. 4. All other streets in the Downtown (general pedestrian-oriented streets): In order to create a unified image in the area, all streets should share common features. At minimum, these should include similar sidewalk scoring patterns, similar paving materials, similar street trees and tree grates, coordinated street furniture, the inclusion of sidewalk neck downs and pedestrian safe zones, removal of pedestrian obstructions, and consolidation of streetscape elements such as newspaper vending boxes, other traffic and directional signage, and pedestrian scale street lighting. 5. Alleyways (minor service-oriented streets): Alleyways serve as secondary circulation and alternative routes for both pedestrians and vehicles to navigate Downtown. They can provide an alternate means of access to shops, restaurants and other commercial uses. Care must be taken in balancing the service function of the alley and making the street safe for pedestrians. 6. Paseos/Multiuse paths (vehicles free pathways): Paseos provide mid-block pedestrian only access. Multiuse paths traverse the civic and park areas. To promote pedestrian circulation throughout the downtown area both should be encouraged in large projects. Design such connections to be interesting places with thoughtful integration into the overall circulation. They should be handicap accessible, illuminated, appropriately landscaped, and paved in materials compatible with their locations and surrounding context. B. Use materials that reinforce the continuity and integrity of the overall Downtown district. Any variations from the standard materials and patterns required by the Design and Construction Standards should be based on a streetscape plan that illustrates how the variation adds to the visual unity and improves the downtown streetscape, adjacent properties, and the overall image of the block. The design and materials should be durable, classic, and elegant including: Note: In general, the predominate material in the Downtown is brick. The use of brick to highlight and define the streetscape zones is especially appropriate in the blocks adjacent to the mall. Other appropriate materials include sandstone, or the use of art work which is stenciled or sandblasted into the concrete surface. Note: Colored concrete scored or formed to imitate brick or stone is inappropriate. 40 Fig. 27 Street Type Key Map (Source: City of Boulder) Canyon Blv d Canyon Blvd Walnut St Walnut St Pearl St Spruce St Pine St Pearl St Spruce St Arapahoe Ave Arapahoe Ave BroadwayBroadway13th St13th St14th St15th St16th St17th St18th St18th St19th St11th St9th St9th StBroadwayPearl St Walnut St Spruce St Boulder Cre e k Bo u l d e r C r e e k Arapahoe A v e Canyon Blv d LEGENDN Parks Vehicle-free pedestrian street Major vehicular through streets North/south pedestrian connectors General pedestrian oriented streets Alleyways Paseos Downtown Urban Design gUiDelines 41 Downtown Urban Design gUiDelines42 Code: See the Design and Construction Standards "Chapter 11 Technical Drawings" and the B.R.C. "Section 9-9- 13, “ Streetscape Design Standards” for additional requirements. Note: Permanent kitchen equipment, new basement level extensions, second floor extensions and greenhouses are generally not permitted within the right-of-way. Note: Light weight or movable handrails, chains, ropes and unsupported railings are inappropriate railing materials. Note: Improvements in the right-of-way shall match the existing materials. Any proposals to differentiate the materials may require approval. For more information visit the City of Boulder Planning website or contact, (303) 441-1880. Note: For more information on patio extensions and cafe seating contact the DMC at (303) 413-7300.SECTION 3: THE PUBLIC REALM1. Brick 2. Sandstone 3. Scored grey concrete 4. Black enamel street furniture and utility elements, e.g. right-of-way lighting, benches, trash receptacles, bollards, etc. 5. Outdoor seating C. Use a basic sidewalk design to unify the visual image of Downtown. In most locations throughout the area, sidewalks average 15 feet wide from curb to property line. Streets should incorporate the following basic sidewalk elements: 1. Frontage Zone The frontage zone width may vary by street and allows for extensions into the right-of-way which create comfortable and attractive sitting areas. Included within this zone are projecting signs, awnings, cafe seating, and gated patio encroachments. • Design public right-of-way extensions that are visually appropriate to the street character. • Seating areas for dining are limited to the width of the building frontage. All tables and chairs are to be removable. • Railing designs should reflect an open, transparent feeling. Visually closed-in railings that “box-in” the extension area are not appropriate. • Consider building programs and spatial layouts which provide alternative solutions to the need for gated, exterior dining areas. There must be a minimum 7' clearance between the edge of the railing or seating area and any vertical obstruction. • Create comfortable and attractive sitting areas, plazas, and small open spaces. Tables and chairs must be movable. • Orient seating to take advantage of views, sunshine in the winter, and shade in the summer. 2. Pedestrian Zone The sidewalk pedestrian-through zone is the travel area designated for pedestrians and must be kept clear of all obstacles. • Pedestrian zones walkway surfaces should be delineated from the curb zone or buffer areas. 3. Curb Zone The curb zone should consist of a 4’ wide area measured perpendicular from the inside of the curb. • Street elements and landscaping should be organized to allow for pedestrian access to adjacent street parking. • On residential transition streets in the Interface Area blocks use landscaping in the curb zone rather than hard surface concrete. 4. Corner Zone At a minimum, the standard corner zone should include the following elements: • A pedestrian area where only essential “regulatory” elements, such as, signal posts, crosswalk signals and lighting are allowed. All other amenities including benches, bike racks, newspaper racks, are prohibited. • Corner “amenity areas” are located at either side of the pedestrian area. Elements such as benches and bike racks should be carefully arranged in an attractive and accessible fashion outside of any pedestrian throughways. Benches should be arranged to facilitate social interaction. 5. Intersections Important streets may require additional material detailing to match adjacent streetscape design and overall block character. • Materials include utilizing brick and scored concrete patterning, similar to adjacent pedestrian and curb zones, in the crosswalks and special paving within intersection squares. Important intersections are the areas between the Civic Park and Downtown Boulder pedestrian mall. Fig. 28 Diagram of the typical sidewalk zones (Source: City of Boulder) Downtown Urban Design gUiDelines 43 A CB A B C Frontage Zone On the Pedestrian Mall - 10’ maximum extension of into the right-of-way. On all other streets - 6’ maximum extension into the right-of-way. Pedestrian Zone On the Pedestrian Mall - The unobstructed pedestrian throughway must be no less than 8 ‘. A 9’6” wide throughway is encouraged. Any type of extensions into the right-of-way must allow for the pedestrian circulation requirements. On all other streets - An unobstructed pedestrian throughway of no less than 7 ‘ wide is required between vertical elements such as trees or poles and buildings. Standard surface materials include brushed natural color gray concrete tooled in a maximum 4’x 4’ square with brick accents. Curb Zone A minimum 4’ curb zone will include trees, bike parking, landscaping strips, furniture, street and/or utility elements. Strandard suface materials include brushed natural color gray concrete tooled in a 2’ x 2’ square pattern, possibly with brick accents. Downtown Urban Design gUiDelines44SECTION 3: THE PUBLIC REALMCode: For more information on landscaping requirements see the City of Boulder "Design and Construction Standards" and the B.R.C. Section 9-9-12, "Landscaping and Screening Standards". Note: Unsuitable streets trees not to be placed in the public right-of-way include Cottonwood, Chinese and Siberian Elm, Poplar, Russian Olive, Silver Maple, Tree of Heaven, Willow, evergreens that create sight obstructions, and clump forms or multi-stem trees. Note: Tree and landscape maintenance on commercially zoned properties, the maintenance of trees, tree grates, and surrounding hard and soft landscaping located in the public right-of-way is the responsibility of the private property owner. This includes all maintenance and repair of landscaping, trees, irrigation, spraying, fertilizing, and replacing plant materials and tree grates. Note: The city provides pruning, removal of street trees in the public right-of-way, safety inspections, and consultation on street trees that may pose a health or safety concern. Note: Contact the DMC at (303) 413-7300 for additional information regarding street furniture, trash receptacles, bicycle stands, and bollard variations for the Pedestrian Mall. 3.3 Landscaping A. Select street trees that are appropriate to their intended location and function. Plant trees that will tolerate full sun, drought, varying soil pH. Keep in mind that the conditions of various planting sites in the Downtown will vary and should be evaluated for individual landscape objectives and suitability to the specific street on which they are to be planted. The following guidelines should be followed: 1. Large trees should be located along Canyon Boulevard, wide right-of-way streets, and principal access streets such as Pearl and Walnut Streets. Large trees should also be used to highlight corners, to provide cover for large plazas, or as accents against the skyline. 2. Large maturing trees may be located on all downtown streets. 3. Small trees should be used to provide seasonal color and a visual focal point for special locations such as a building entrance, corner area, sitting area, bus stop, or other significant area or view corridor. 4. Install street trees in tree grates at areas of adjacent parking and high pedestrian traffic, except at locations where they occur in special raised planters in the curb zone, in large planted areas that are integrated with a sidewalk area, and in locations where existing trees located in the curb zones have a root system that has pushed up above grade where the use of a grate will injure the tree. 5. Maintain at least a 10 foot distance between tree trunk and building line. This refers to the distance between a tree and building, not the distance necessary to maintain an unobstructed pedestrian area between a tree, as a vertical element, and a railing that encloses a sidewalk restaurant 6. Where tree grates are used they should be aligned with paving pattern score lines and be placed with careful consideration of sidewalk use, such as a sidewalk cafe or curb cuts. 7. Consider alternative methods to increase tree soil volume, e.g. modular, pre-engineered suspended pavement and structural cell systems. B. Select ground level plants that suit their location and function. 1. Use landscaping, shrubs and ground cover to accent areas. 2. Limit the use of annuals and high maintenance plants to the planting beds in the Downtown Boulder pedestrian mall. Use drought tolerant, climate appropriate landscaping, including shrubs, flowering perennials, ground cover, and ornamental grasses in planter beds. 3. Do not use gravel or rough stone in place of ground cover in the curb zone. 4. Whenever feasible, flowers and ornamental grasses should be used in combination to accent gateway locations and special sites. 5. Plantings are preferred in natural, at-grade planting beds rather than planter pots or other containers. 6. Consider maintenance requirements in the placement and design of these features. C. Maintain the character of Canyon Boulevard. 1. Continue the large tree rows on either side of the street and center landscape median. 2. In general, trees and other plant material should be arranged in an urban linear pattern that parallels the street rather than a less formal random arrangement. 3. The primary trees along Canyon do not need to be planted with tree grates. 4. The median should be planted to enhance the “boulevard” quality of the corridor. 5. Incorporate grasses, paved areas or ground covers within the overall design of tree rows. Fig. 29 Diagram of the typical corner and intersection zones (Source: City of Boulder) Downtown Urban Design gUiDelines 45 Corner Zone - A pedestrian area or clear zone that is free of obstacles and lined up with the sidewalk pedestrian zone. Standard surface treatment includes brushed natural gray concrete scored in a 2’x 2’ square pattern parallel to the street. Crosswalks - Pedestrian crosswalks should be a minimum of 10’ wide with a 1’ buer on either side. Standard surface treatment includes truncated dome ramps and marking the crosswalk zone. A C B Corner “amenity areas” - The amenity areas may incorporate benches, bike racks, news racks, and similar elements. Standard surface treatment includes brushed natural gray concrete scored in a 4’x 4’ square pattern and may have brick detailing. D Intersection Squares - the center area of intersections have the same surface material as the surrounding street surfaces. E Pedestrian Zone C D C A F BE B F Curb Zone Fig. 30 Brick, sandstone, and scored concrete defining a corner zone (Source: City of Boulder) Fig. 31 Brick pavers and street features within the Pedestrian Mall (Source: City of Boulder) Fig. 32 Typical bicycle rack and tree grate (Source: City of Boulder) Downtown Urban Design gUiDelines46SECTION 3: THE PUBLIC REALM Fig. 33 View of compatible patio extension with sandstone posts and iron railings (Source: City of Boulder) Downtown Urban Design gUiDelines 47 Downtown Urban Design gUiDelines48SECTION 3: THE PUBLIC REALM Note: The Arts Commission, DMC, DAB, and LB are among the groups involved in making public art decisions in the Downtown. 3.4 Street Furnishings A. Use street furnishings to create a unified visual appearance in Downtown. B. In general, install standard benches, trash receptacles, appropriately sized bollards, pedestrian-scale street lighting, and bike stands in durable black metal to unify the visual quality of the Downtown. C. Strategically locate newspaper stands, kiosks and other furniture adjacent high-traffic areas, e.g. bus stops, intersections, etc. D. Create attractive, safe and comfortable bus stops crafted in durable and elegant materials. 3.5 Historic Features A. Preserve historic features of the streetscape. Whenever possible, preserve, restore, and reuse historic fixtures of the streetscape, such as flagstone sidewalks, globe light fixtures, or any other existing historic features located in the public right- of-way. B. Historic signs, such as those painted on side walls, should be preserved. C. Extensions into the right-of-way involving historic resources should be compatible and not substantially alter the property. 3.6 Public Art A. Enrich the downtown with public art and carefully site art within appropriate areas of the public realm. Consider the context, materials, purpose of the artwork at the proposed site. B. Freestanding artwork should not obscure building elements. Thoughtfully integrated artwork may be incorporated into the surface or facade design. C. Artwork may be utilized as gateway features within discrete areas of Downtown. D. Public art should be complementary and subordinate to associated historic properties and complement the period of significance of the building or district. Fig. 34 West Pearl gateway obelisk (Source: City of Boulder) Downtown Urban Design gUiDelines 49