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HomeMy WebLinkAboutExhibit A_HPGuidelinesCriteria Page 1 of 12 Exhibit A Historic Preservation Design Guidelines Criteria Staff Findings Note: Staff findings on the guidelines begins on page 11 of this exhibit. 26.415.070.D Major Development. No building, structure or landscape shall be erected, constructed, enlarged, altered, repaired, relocated or improved involving a designated historic property or a property located within a Historic District until plans or sufficient information have been submitted to the Community Development Director and approved in accordance with the procedures established for their review. An application for a building permit cannot be submitted without a development order. 3. Conceptual Development Plan Review b) The procedures for the review of conceptual development plans for major development projects are as follows: 1) The Community Development Director shall review the application materials submitted for conceptual or final development plan approval. If they are determined to be complete, the applicant will be notified in writing of this and a public hearing before the HPC shall be scheduled. Notice of the hearing shall be provided pursuant to Section 26.304.060.E.3 Paragraphs a, b and c. 2) Staff shall review the submittal material and prepare a report that analyzes the project's conformance with the design guidelines and other applicable Land Use Code sections. This report will be transmitted to the HPC with relevant information on the proposed project and a recommendation to continue, approve, disapprove or approve with conditions and the reasons for the recommendation. The HPC will review the application, the staff analysis report and the evidence presented at the hearing to determine the project's conformance with the City Historic Preservation Design Guidelines. 3) The HPC may approve, disapprove, approve with conditions or continue the application to obtain additional information necessary to make a decision to approve or deny. 4) A resolution of the HPC action shall be forwarded to the City Council in accordance with Section 26.415.120 - Appeals, notice to City Council, and call-up. No applications for Final Development Plan shall be accepted by the City and no associated permits shall be issued until the City Council takes action as described in said section. Page 2 of 12 Page 3 of 12 Relevant Historic Preservation Design Guidelines: 1.1 All projects shall respect the historic development pattern or context of the block, neighborhood or district. • Building footprint and location should reinforce the traditional patterns of the neighborhood. • Allow for some porosity on a site. In a residential project, setback to setback development is typically uncharacteristic of the historic context. Do not design a project which leaves no useful open space visible from the street. 1.5 Maintain the historic hierarchy of spaces. • Reflect the established progression of public to private spaces from the public sidewalk to a semi-public walkway, to a semi private entry feature, to private spaces. 1.6 Provide a simple walkway running perpendicular from the street to the front entry on residential projects. • Meandering walkways are not allowed, except where it is needed to avoid a tree or is typical of the period of significance. • Use paving materials that are similar to those used historically for the building style and install them in the manner that they would have been used historically. For example on an Aspen Page 4 of 12 Victorian landmark set flagstone pavers in sand, rather than in concrete. Light grey concrete, brick or red sandstone are appropriate private walkway materials for most landmarks. • The width of a new entry sidewalk should generally be three feet or less for residential properties. A wider sidewalk may be appropriate for an AspenModern property. 1.7 Provide positive open space within a project site. • Ensure that open space on site is meaningful and consolidated into a few large spaces rather than many small unusable areas. • Open space should be designed to support and complement the historic building. 1.8 Consider stormwater quality needs early in the design process. • When included in the initial planning for a project, stormwater quality facilities can be better integrated into the proposal. All landscape plans presented for HPC review must include at least a preliminary representation of the stormwater design. A more detailed design must be reviewed and approved by Planning and Engineering prior to building permit submittal. • Site designs and stormwater management should provide positive drainage away from the historic landmark, preserve the use of natural drainage and treatment systems of the site, reduce the generation of additional stormwater runoff, and increase infiltration into the ground. Stormwater facilities and conveyances located in front of a landmark should have minimal visual impact when viewed from the public right of way. • Refer to City Engineering for additional guidance and requirements. 1.11 Preserve and maintain historically significant landscaping on site, particularly landmark trees and shrubs. • Retaining historic planting beds and landscape features is encouraged. • Protect historically significant vegetation during construction to avoid damage. Removal of damaged, aged, or diseased trees must be approved by the Parks Department. • If a significant tree must be removed, replace it with the same or similar species in coordination with the Parks Department. • The removal of non-historic planting schemes is encouraged. • Consider restoring the original landscape if information is available, including original plant materials. 1.27 Preserve and maintain significant landscaping on site. • Protect established vegetation during any construction. • If any tree or shrub needs to be removed, replace it with the same or similar species. • New planting should be of a species used historically or a similar species. • Maintain and preserve any gardens and/or ornamental planting on the site. • Maintain and preserve any historic landscape elements. Page 5 of 12 2.1 Preserve original building materials. • Do not remove siding that is in good condition or that can be repaired in place. • Masonry features that define the overall historic character, such as walls, cornices, pediments, steps and foundations, should be preserved. • Avoid rebuilding a major portion of an exterior wall that could be repaired in place. Reconstruction may result in a building which no longer retains its historic integrity. • Original AspenModern materials may be replaced in kind if it has been determined that the weathering detracts from the original design intent or philosophy. 2.3 Match the original material in composition, scale and finish when replacing materials on primary surfaces. • If the original material is wood clapboard for example, then the replacement material must be wood as well. It should match the original in size, and the amount of exposed lap and finish. • Replace only the amount required. If a few boards are damaged beyond repair, then only those should be replaced, not the entire wall. For AspenModern buildings, sometimes the replacement of a larger area is required to preserve the integrity of the design intent. 2.6 Remove layers that cover the original material. • Once the non-historic siding is removed, repair the original, underlying material. 3.1 Preserve the functional and decorative features of a historic window. • Features important to the character of a window include its frame, sash, muntins/mullions, sills, heads, jambs, moldings, operations, and groupings of windows. • Repair frames and sashes rather than replacing them. • Preserve the original glass. If original Victorian era glass is broken, consider using restoration glass for the repair. 3.2 Preserve the position, number, and arrangement of historic windows in a building wall. • Enclosing a historic window is inappropriate. • Do not change the size of an original window opening. 3.5 Preserve the size and proportion of a historic window opening. • Changing the window opening is not permitted. • Consider restoring an original window opening that was enclosed in the past. 3.7 Adding new openings on a historic structure is generally not allowed. • Greater flexibility in installing new windows may be considered on rear or secondary walls. • New windows should be similar in scale to the historic openings on the building, but should in some way be distinguishable as new, through the use of somewhat different detailing, etc. • Preserve the historic ratio of window openings to solid wall on a façade. Page 6 of 12 • Significantly increasing the amount of glass on a character defining façade will negatively affect the integrity of a structure. 4.1 Preserve historically significant doors. • Maintain features important to the character of a historic doorway. These include the door, door frame, screen door, threshold, glass panes, paneling, hardware, detailing, transoms and flanking sidelights. • Do not change the position and function of original front doors and primary entrances. • If a secondary entrance must be sealed shut, any work that is done must be reversible so that the door can be used at a later time, if necessary. Also, keep the door in place, in its historic position. • Previously enclosed original doors should be reopened when possible. 4.2 Maintain the original size of a door and its opening. • Altering its size and shape is inappropriate. It should not be widened or raised in height. 4.5 Adding new doors on a historic building is generally not allowed. • Place new doors in any proposed addition rather than altering the historic resource. • Greater flexibility in installing a door in a new location may be considered on rear or secondary walls. • A new door in a new location should be similar in scale and style to historic openings on the building and should be a product of its own time. • Preserve the historic ratio of openings to solid wall on a façade. Significantly increasing the openings on a character defining façade negatively affects the integrity of a structure. 5.1 Preserve an original porch or balcony. • Replace missing posts and railings when necessary. Match the original proportions, material and spacing of balusters. • Expanding the size of a historic porch or balcony is inappropriate. 6.1 Preserve significant architectural features. • Repair only those features that are deteriorated. • Patch, piece-in, splice, or consolidate to repair the existing materials, using recognized preservation methods whenever possible. • On AspenModern properties, repair is preferred, however, it may be more important to preserve the integrity of the original design intent, such as crisp edges, rather than to retain heavily deteriorated material. 7.1 Preserve the original form of a roof. • Do not alter the angle of a historic roof. Preserve the orientation and slope of the roof as seen from the street. • Retain and repair original and decorative roof detailing. Page 7 of 12 • Where the original roof form has been altered, consider restoration. 7.2 Preserve the original eave depth. • Overhangs contribute to the scale and detailing of a historic resource. • AspenModern properties typically have very deep or extremely minimal overhangs that are key character defining features of the architectural style. 9.1 Developing a basement by underpinning and excavating while the historic structure remains in place may help to preserve the historic fabric. • This activity will require the same level of documentation, structural assessment, and posting of financial assurances as a building relocation. 9.3 Site a relocated structure in a position similar to its historic orientation. • It must face the same direction and have a relatively similar setback. In general, a forward movement, rather than a lateral movement is preferred. HPC will consider setback variations where appropriate. • A primary structure may not be moved to the rear of the parcel to accommodate a new building in front of it. • Be aware of potential restrictions against locating buildings too close to mature trees. Consult with the City Forester early in the design process. Do not relocate a building so that it becomes obscured by trees. 9.4 Position a relocated structure at its historic elevation above grade. • Raising the finished floor of the building slightly above its original elevation is acceptable if needed to address drainage issues. A substantial change in position relative to grade is inappropriate. • Avoid making design decisions that require code related alterations which could have been avoided. In particular, consider how the relationship to grade could result in non-historic guardrails, etc. 9.5 A new foundation shall appear similar in design and materials to the historic foundation. • On modest structures, a simple foundation is appropriate. Constructing a stone foundation on a miner’s cottage where there is no evidence that one existed historically is out of character and is not allowed. • Exposed concrete or painted metal flashing are generally appropriate. • Where a stone or brick foundation existed historically, it must be replicated, ideally using stone salvaged from the original foundation as a veneer. The replacement must be similar in the cut of the stone and design of the mortar joints. • New AspenModern foundations shall be handled on a case by case basis to ensure preservation of the design intent. 9.6 Minimize the visual impact of lightwells. • The size of any lightwell that faces a street should be minimized. Page 8 of 12 • Lightwells must be placed so that they are not immediately adjacent to character defining features, such as front porches. • Lightwells must be protected with a flat grate, rather than a railing or may not be visible from a street. • Lightwells that face a street must abut the building foundation and generally may not “float” in the landscape except where they are screened, or on an AspenModern site. 10.2 A more recent addition that is not historically significant may be removed. • For Aspen Victorian properties, HPC generally relies on the 1904 Sanborn Fire Insurance maps to determine which portions of a building are historically significant and must be preserved. • HPC may insist on the removal of non-historic construction that is considered to be detrimental to the historic resource in any case when preservation benefits or variations are being approved. 10.3 Design a new addition such that one’s ability to interpret the historic character of the primary building is maintained. • A new addition must be compatible with the historic character of the primary building. • An addition must be subordinate, deferential, modest, and secondary in comparison to the architectural character of the primary building. • An addition that imitates the primary building’s historic style is not allowed. For example, a new faux Victorian detailed addition is inappropriate on an Aspen Victorian home. • An addition that covers historically significant features is inappropriate. • Proposals on corner lots require particular attention to creating compatibility. 10.4 The historic resource is to be the focus of the property, the entry point, and the predominant structure as viewed from the street. • The historic resource must be visually dominant on the site and must be distinguishable against the addition. • The total above grade floor area of an addition may be no more than 100% of the above grade floor area of the original historic resource. All other above grade development must be completely detached. HPC may consider exceptions to this policy if two or more of the following are met: o The proposed addition is all one story o The footprint of the new addition is closely related to the footprint of the historic resource and the proposed design is particularly sensitive to the scale and proportions of the historic resource o The project involves the demolition and replacement of an older addition that is considered to have been particularly detrimental to the historic resource o The interior of the resource is fully utilized, containing the same number of usable floors as existed historically Page 9 of 12 o The project is on a large lot, allowing the addition to have a significant setback from the street o There are no variance requests in the application other than those related to historic conditions that aren’t being changed o The project is proposed as part of a voluntary AspenModern designation, or o The property is affected by non-preservation related site specific constraints such as trees that must be preserved, Environmentally Sensitive Areas review, etc. 10.6 Design a new addition to be recognized as a product of its own time. • An addition shall be distinguishable from the historic building and still be visually compatible with historic features. • A change in setbacks of the addition from the historic building, a subtle change in material, or a modern interpretation of a historic style are all techniques that may be considered to help define a change from historic construction to new construction. • Do not reference historic styles that have no basis in Aspen. • Consider these three aspects of an addition; form, materials, and fenestration. An addition must relate strongly to the historic resource in at least two of these elements. Departing from the historic resource in one of these categories allows for creativity and a contemporary design response. • Note that on a corner lot, departing from the form of the historic resource may not be allowed. • There is a spectrum of appropriate solutions to distinguishing new from old portions of a development. Some resources of particularly high significance or integrity may not be the right instance for a contrasting addition. 10.7 When planning an addition to a building in a historic district, preserve historic alignments on the street. • Some roof lines and porch eaves on historic buildings may align at approximately the same height. An addition can not be placed in a location where these relationships would be altered or obscured. 10.8 Design an addition to be compatible in size and scale with the main building. • An addition that is lower than, or similar to the height of the primary building, is preferred. 10.9 If the addition is taller than a historic building, set it back from significant façades and use a “connector” to link it to the historic building. • Only a one-story connector is allowed. • Usable space, including decks, is not allowed on top of connectors unless the connector has limited visibility and the deck is shielded with a solid parapet wall. • In all cases, the connector must attach to the historic resource underneath the eave. • The connector shall be a minimum of 10 feet long between the addition and the primary building. Page 10 of 12 • Minimize the width of the connector. Ideally, it is no more than a passage between the historic resource and addition. The connector must reveal the original building corners. The connector may not be as wide as the historic resource. • Any street-facing doors installed in the connector must be minimized in height and width and accessed by a secondary pathway. See guideline 4.1 for further information. 10.10 Place an addition at the rear of a primary building or set it back substantially from the front to minimize the visual impact on the historic structure and to allow the original proportions and character to remain prominent. • Locating an addition at the front of a primary building is inappropriate. • Additions to the side of a primary building are handled on a case-by-case basis and are approved based on site specific constraints that restrict rear additions. • Additional floor area may also be located under the building in a basement which will not alter the exterior mass of a building. 10.11 Roof forms shall be compatible with the historic building. • A simple roof form that does not compete with the historic building is appropriate. • On Aspen Victorian properties, a flat roof may only be used on an addition to a gable roofed structure if the addition is entirely one story in height, or if the flat roofed areas are limited, but the addition is primarily a pitched roof. 10.12 Design an addition to a historic structure that does not destroy or obscure historically important architectural features. • Loss or alteration of architectural details, cornices, and eavelines must be avoided. 12.4 Minimize the visual impacts of utilitarian areas, such as mechanical equipment and trash storage. • Place mechanical equipment on the ground where it can be screened. • Mechanical equipment may only be mounted on a building on an alley façade. • Rooftop mechanical equipment or vents must be grouped together to minimize their visual impact. Where rooftop units are visible, it may be appropriate to provide screening with materials that are compatible with those of the building itself. Use the smallest, low profile units available for the purpose. • Window air conditioning units are not allowed. • Minimize the visual impacts of utility connections and service boxes. Group them in a discrete location. Use pedestals when possible, rather than mounting on a historic building. • Paint mechanical equipment in a neutral color to minimize their appearance by blending with their backgrounds • In general, mechanical equipment should be vented through the roof, rather than a wall, in a manner that has the least visual impact possible. Page 11 of 12 • Avoid surface mounted conduit on historic structures. Staff Finding: The applicable chapters of the design guidelines are as follows: site planning, rehabilitation, relocation, building additions, and service areas. All relevant Design Guidelines in Chapters 2, 3, 4, 5, 6 and 7 related to the restoration and rehabilitation efforts need to be reviewed in detail as part of the Final review, permit submittal and/or in the field to ensure no historic fabric is being removed. A number of historic conditions are concealed at this time due to the asbestos shingles and the overframed front porch roof, which should be restored. Further investigation of the building will be a condition of Final approval. In general, staff finds that the guidelines are met, or can be met with conditions. One guideline, that needs clarification is 1.8, related to stormwater needs. The applicant has been delayed in receiving a stormwater plan from their civil engineer. The architect proposed a basic concept to drain towards a drywell at the center of the site, however City Engineering has indicated that drywells must be at least 10’ from a property line, which may not be possible. Engineering also views drywells as a last choice. They are encouraging the inclusion of green roofs in this plan. That appears to be possible on the addition, however it could change roof forms, so staff recommends condition of the review for restudy. Regarding the addition, discussion is needed on at least two guidelines. First, guideline 10.4 indicates that the addition can’t be larger than the historic resource. The above grade floor area of the historic resource is approximately 724 square feet and the addition is approximately 1,018 square feet. An exception is allowable if certain criteria are met, which staff finds is the case as follows: The total above grade floor area of an addition may be no more than 100% of the above grade floor area of the original historic resource. All other above grade development must be completely detached. HPC may consider exceptions to this policy if two or more of the following are met: o The proposed addition is all one story o The footprint of the new addition is closely related to the footprint of the historic resource and the proposed design is particularly sensitive to the scale and proportions of the historic resource o The project involves the demolition and replacement of an older addition that is considered to have been particularly detrimental to the historic resource o The interior of the resource is fully utilized, containing the same number of usable floors as existed historically o The project is on a large lot, allowing the addition to have a significant setback from the street o There are no variance requests in the application other than those related to historic conditions that aren’t being changed Page 12 of 12 o The project is proposed as part of a voluntary AspenModern designation, or o The property is affected by non-preservation related site specific constraints such as trees that must be preserved, Environmentally Sensitive Areas review, etc. Guideline 10.6 has to do with architectural compatibility between the resource and addition: o Consider these three aspects of an addition; form, materials, and fenestration. An addition must relate strongly to the historic resource in at least two of these elements. Departing from the historic resource in one of these categories allows for creativity and a contemporary design response. The architect appears to plan to vary from the fenestration on the historic house. The materials may be similar between the two elements, but staff does not find that form is met as a second related characteristic. In particular, greater compatibility could be achieved in the roof design, as further discussed in guideline 10.11. 10.11 Roof forms shall be compatible with the historic building. • A simple roof form that does not compete with the historic building is appropriate. • On Aspen Victorian properties, a flat roof may only be used on an addition to a gable roofed structure if the addition is entirely one story in height, or if the flat roofed areas are limited, but the addition is primarily a pitched roof. The pitched roof on the addition is 7:12, where the historic resource is 9:12. Staff recommends the addition match the resource and that the spring point on the upper floor be reduced to achieve this. Staff recommends restudy of the roof forms on the east side of the gable to simplify and relate to the resource. The long slope over the stair is particularly unrelated. In summary, staff recommends continuation for restudy of the elements noted above.