23.48.645

A. Highrise floor area limits. All highrise structures are subject to a limit on the floor area of stories above 45 feet in height except that, on a lot that includes a light rail transit station, the limit on floor area only applies to stories above 55 feet in height. 1. The height above which the highrise floor area limit applies is measured from the average grade level. Stories that do not exceed 45 feet in height or, on a lot that includes a light rail transit station, stories that do not exceed 55 feet in height, are not subject to a floor area limit. 2. Highrise floor area limits in the SM-U 75-240 and SM-U 95-320 zones are shown on Table A for 23.48.645. Table A for 23.48.645 Highrise floor area limits in the SM-U 75-240 and SM-U 95-320 zones Height of structure Average gross floor area for all stories above 45 feet 1 Maximum gross floor area of any single story above 45 feet 1 Greater than the first height limit of the height suffix, excluding rooftop features, but not exceeding 160 feet in height 20,000 square feet for stories in non-residential use, except as provided in subsection 23.48.645.A.4; or 12,000 square feet for stories in residential use 2 24,000 square feet for stories in non-residential use; or 13,000 square feet for stories in residential use 2 Greater than 160 feet but not exceeding 240 feet in height 10,500 square feet 11,500 square feet Greater than 240 feet in height 9,500 square feet 10,500 square feet Footnotes to Table A for 23.48.645 1 On a lot that includes a light rail transit station, the limit on the floor area of stories applies to stories above 55 feet in height. 2 For stories that include a mix of non-residential and residential uses, the applicable floor area limit shall be the limit that applies to the use that accounts for more than 50 percent of the total floor area of the story, or the greater of the two floor area limits if the story includes equal amounts of residential and non-residential uses. 3. In the SM-U/R 75-240 zone, for highrise structures, the gross floor area limit of stories or portions of stories that extend above 45 feet in height is 10,500 square feet. 4. In the SM-U 75-240 and SM-U 95-320 zones, for stories subject to a floor area limit under subsection 23.48.645.A.2, the average and maximum gross floor area limit is 24,000 square feet up to 160 feet if the following apply: a. For each story subject to a floor area limit up to 160 feet in height, a minimum of 50 percent of the floor area is in research and development laboratory uses; and b. The minimum floor-to-floor height of each story subject to a floor area limit up to 160 feet in height is 14 feet. B. Upper-level setbacks in SM-U 75-240 and SM-U 95-320 zones. The following upper-level setbacks are required, and the height above which the setback is required shall be measured from the midpoint of the lot line from which the setback is required: 1. On lots that do not include highrise structures, an average setback of 10 feet is required from all abutting street lot lines for any portion of a structure that exceeds 65 feet in height. The maximum depth of a setback that can be used for calculating the average is 20 feet. 2. For a lot that is across a street from a lot in a LR zone or a MR zone, portions of any structure above 65 feet in height are required to set back an average of 10 feet from any portion of the street lot line that abuts the separating street. The maximum depth of a setback that can be used for calculating the average is 20 feet. 3. For a lot in the SM-U 95-320 zone that abuts a lot in a MR zone, portions of any structure above 65 feet in height are required to set back a minimum of 15 feet from the abutting lot line. C. Upper-level setbacks in the SM-U/R 75-240 zone. The minimum required upper-level setbacks in the SM-U/R 75-240 zone are shown on Table B for 23.48.645. Table B for 23.48.645 Required upper-level setbacks in the SM-U/R 75-240 zone Lot line from which required setback is measured: Minimum setback required for portions of a structure at or above specified heights Rear lot line that abuts an alley Portions of a structure 45 feet or less in height: None required Portions of a structure greater than 45 feet in height: 10 feet minimum Lot line that abuts neither a street nor an alley For structures 75 feet in height or less: 7 feet average; 5 feet minimum 1 For structures that exceed 75 feet in height, portions of a structure 45 feet or less in height: 7 feet average; 5 feet minimum 1 and Portions of a structure greater than 45 feet in height: 15 feet minimum Footnotes to Table B for 23.48.645 1 No setback is required along lot lines where an existing structure is built to the abutting lot line. D. Side lot line setbacks. In the SM-U 75-240 and SM-U 95-320 zones, a minimum setback of 15 feet is required from any side lot line that is not a street or alley lot line for all portions of a highrise structure exceeding the midrise height limit of the zone. E. Separation. On lots with structures that exceed the midrise height limit, excluding rooftop features otherwise allowed above the height limit by subsection 23.48.025.C, separation between structures or portions of the same structure is required as follows: 1. On separate lots. A minimum separation of 75 feet is required between highrise portions of structures on a lot and any existing highrise structures located on a separate lot in the same block, as shown on Exhibit A for 23.48.645 ; and 2. Within a lot. A minimum separation of 75 feet is required between any highrise portion of a structure and all other portions of the same structure that exceed 45 feet in height, or portions of other structures on the lot that exceed 45 feet in height, as shown on Exhibit A for 23.48.645. Exhibit A for 23.48.645 Required separation between highrise structures 3. For the purposes of this subsection 23.48.645.E, the separation requirements for lots separated by an alley that are combined under the provisions of Section 23.48.627 shall be applied according to subsection 23.48.645.E.1, as if the lots were separate lots on the same block. 4. If the presence of an existing highrise structure would preclude the addition of another highrise structure on a different block front of the same block, the Director may, as a special exception according to Chapter 23.76 , reduce the required separation of this subsection 23.48.645.E by up to 20 percent. In determining the amount of reduction in separation allowed, the Director shall consider the following factors that may support the reduction in separation between structures and offset any related impacts: a. The potential impact of the additional highrise structure on adjacent structures located within the same block and on adjacent blocks, in terms of views, privacy, and shadows; b. Potential public benefits related to the development that offset the impact of the reduction in required separation between structures, such as the provision of public open space, improvements to a designated green street, or other streetscape improvements, or the preservation of a Landmark structure; c. The potential impact on the public environment, including shadow and view impacts on nearby streets and public open spaces; and d. Design characteristics of the additional structure, such as overall bulk and massing, orientation, facade treatments and transparency, visual interest, and other features that address the relationship between the two structures. 5. For purposes of this subsection 23.48.645.E, a highrise structure is considered to be "existing" and must be taken into consideration when other highrise structures are proposed, under any of the following circumstances: a. The highrise structure is physically present, except that a highrise structure that is physically present is not considered "existing" if the owner of the lot where the highrise structure is located has applied to the Director for a permit to demolish the highrise structure and provided that no building permit for the proposed highrise structure is issued until the demolition of the highrise structure that is physically present has been completed; b. The highrise structure is a proposed highrise structure for which a complete application for a Master Use Permit or building permit has been submitted, provided that: i. The application has not been withdrawn or cancelled without the highrise structure having been constructed; and ii. If a decision on that application has been published or a permit on the application has been issued, the decision or permit has not expired, and has not been withdrawn, cancelled, or invalidated, without the highrise structure having been constructed. c. The highrise structure is a proposed highrise structure for which a complete application for early design guidance has been filed and a complete application for a Master Use Permit or building permit has not been submitted, provided that the early design guidance application will not qualify a proposed highrise structure as an existing highrise structure if a complete Master Use Permit application is not submitted within 90 days of the date of the early design guidance public meeting if one is required, or within 90 days of the date the Director provides guidance if no early design guidance public meeting is required, or within 150 days of the first early design guidance public meeting if more than one early design guidance public meeting is held. F. Projections. The first 4 feet of horizontal projection of decks, balconies with open railings, eaves, cornices, gutters, and similar architectural features are permitted in the upper-level setbacks required in subsections 23.48.645.B, 23.48.645.C, and 23.48.645.D, and in the separation area required in subsection 23.48.645.E. (Ord. 125603 , § 41, 2018; Ord. 125267 , § 26, 2017.)