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Explanation and Examples
This guideline restates the City's SEPA (State Environmental Policy Act) Policy on Height, Bulk and Scale. Development projects in multifamily and commercial zones may create substantial adverse impacts resulting from incongruous height, bulk and scale. For projects udergoing Design Review, the analysis and mitigation of height, bulk and scale impacts will be accomplished through the Design Review process. Careful siting and design treatment based on the technique described in this and other design guidelines will help to mitigate some height, bulk and scale impacts; in other cases, actual reduction in the height, bulk and scale of a project may be necessary to adequately mitigate impacts. Design Review should not result in siginificant reductions in a project's actual height, bulk and scale unless neccessary to comply with this guideline.
Height, bulk and scale mitigation may be required in two general circumstances:
- Projects on or near the edge of a less intensive zone. A substantial incompatibility in scale may result from different development standards in the two zones and may be compounded by physical factors such a s large deveolpment sites, slopes or lot orientation.
- Projects proposed on sites with unusual physical characteristics such as large lot size, or unusual shape, or topography where buildings may appear substantially greater in height, bulk and scale than that generally anticipated for the area.
Factors to consider in analyzing potential height, bulk and scale impacts include:
- distance from the edge of a less intensive zone
- differences in development standards between abutting zones (allowable building height, width, lot coverage, etc.)
- effect of site size and shape
- height, bulk and scale relationships resulting from lot orientation (e.g. back lot line to back lot line vs. back lot line to side lot line)
- type and amount of seperation between lots in the different zones (e.g. seperation by only a property line, by an alley or street, or by other physical features such as grade changes).
In some cases, careful siting and design treatment may be sufficient to achieve reasonable transition and mitigation of height, bulk and scale impacts. Some techniques for achieving compaitibility are as follows:
- use of architectural style, details (such as roof lines or fenestration), color or materials that derive from the less intensive zone. (See also Guideline C-1: Architectural Context.)
- creative use of landscaping or other screening
- location of features on-site to facilitate transition, such as locating required open space on the zone edge so the building us farther from the lower intensity zone.
- treating topographic conditions in ways that minimize impacts on neighboring development, such as by using a rockery rather than a retaining wall to give a more human scale to a project, or stepping a project down a hillside.
- in a mixed-use project, siting the more compatible use near the zone edge.
In some cases, reductions in the actual height, bulk and scale of the proposed structure may be necessary in order to mitigate adverse impacts and achieve an acceptable level of compatitibility. Some techniques which can be used in these cases include:
- articulating the building's facades vertically or horizontally in intervals that conform to existing structures or platting pattern.
- increasing building setbacks from the zone edge at ground level
- reducing the bulk of the building's upper floors
- limiting the length of, or otherwise modifying, facades
- reducing the height of the structure
- reducing the number or size of accessory structures.
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