Lots in the SM-SLU 100/65-145, SM-SLU 85/65-160, SM-SLU 175/85-280, SM-SLU 85-280, and SM-SLU 240/125-440 zones are subject to upper-level development standards that may include upper-level floor area limits, gross floor area limits and podium heights, upper-level setbacks, facade modulation, maximum facade widths, a limit on the number of towers per block, and tower separation requirements, as specified in this Section 23.48.245 . For the purpose of this Section 23.48.245 , a tower is a structure that exceeds a height of 65 feet for the SM-SLU 100/65-145 and SM-SLU 85/65-160 zones, 85 feet for the SM-SLU 175/85-280 and SM-SLU 85-280 zones, or 125 feet for the SM-SLU 240/125-440 zone. A. Upper-level floor area limit. For residential towers, the average gross floor area of all stories above the podium height specified on Map A for 23.48.245 shall not exceed 50 percent of the lot area, provided that: 1. In no case shall the gross floor area of stories above the podium height exceed the gross floor area limits of subsection 23.48.245.B.2; and 2. The limit on towers per block in subsection 23.48.245.F applies. B. Floor area limits and podium heights. The following provisions apply to development in the SM-SLU 100/65-145, SM-SLU 85-280, SM-SLU 85/65-160, SM-SLU 175/85-280, and SM-SLU 240/125-440 zones located within the South Lake Union Regional Center: 1. Floor area limit for structures or portions of structures occupied by nonresidential uses: a. Except as specified in subsections 23.48.245.B.1.b and 23.48.245.B.1.c, there is no floor area limit for nonresidential uses in a structure or portion of structure that does not contain nonresidential uses above 85 feet in height. b. There is no floor area limit for a structure that includes research and development uses and the uses are in a structure that does not exceed a height of 105 feet, provided that the following conditions are met: 1) A minimum of two floors in the structure are occupied by research and development uses and have a floor-to-floor height of at least 14 feet; and 2) The structure has no more than seven stories above existing or finished grade, whichever is lower, as measured from the lowest story to the highest story of the structure but not including rooftop features permitted under subsection 23.48.025.C. The lowest story shall not include a story that is partially below grade and extends no higher than 4 feet above existing or finished grade, whichever is lower. c. Within locations in the SM-SLU 175/85-280 zone meeting the standards in subsection 23.48.230.B for extra height in South Lake Union Regional Center, there is no floor area limit for structures that do not exceed a height of 120 feet and that are designed for research and development laboratory use and administrative office associated with research and development laboratories. d. For structures or portions of structures with nonresidential uses that exceed a height of 85 feet, or that exceed the height of 105 feet under the provisions of subsection 23.48.245.B.1.b, or 120 feet under subsection 23.48.245.B.1.c, each story of the structure above the specified podium height indicated for the lot on Map A for 23.48.245, excluding rooftop features or stories with rooftop features that are otherwise permitted above the height limit under the provisions of subsection 23.48.025.C, is limited to a maximum gross floor area of 24,000 square feet per story, except that the average gross floor area for stories above the specified podium height is 30,000 square feet for structures on a lot that meets the following conditions: 1) The lot has a minimum area of 60,000 square feet; and 2) The lot includes an existing open space or a qualifying Landmark structure and is permitted an additional increment of FAR above the base FAR, as permitted in subsection 23.48.220.A.3. 2. Floor area limit for residential towers. For a structure with residential use that exceeds the base height limit established for residential uses in the zone under subsection 23.48.225.A.1, the following maximum gross floor area limit applies: a. For a structure that does not exceed a height of 160 feet, excluding rooftop features or stories with rooftop features that are otherwise permitted above the height limit under the provisions of subsection 23.48.025.C, the gross floor area for stories with residential use that extend above the podium height indicated for the lot on Map A for 23.48.245 shall not exceed 12,500 square feet for each story, or the floor size established by the upper-level floor area limit in subsection 23.48.245.A, whichever is less. b. For a structure that exceeds a height of 160 feet, the following limits apply: 1) The average gross floor area for all stories with residential use that extend above the podium height indicated for the lot on Map A for 23.48.245, and extending up to the maximum height limit, shall not exceed 10,500 square feet, or the floor size established by the upper-level floor area limit in subsection 23.48.245.A, whichever is less, except as allowed in subsection 23.48.245.A. 2) The gross floor area of any single residential story above the podium height shall not exceed 11,500 square feet. 3. Floor area limit for mixed-use development. This subsection 23.48.245.B.3 applies to structures or portions of structures that include both residential and non-residential uses, as provided for in subsection 23.48.220.A.2. a. For a story that includes both residential and non-residential uses, the gross floor area limit for all uses combined shall not exceed the floor area limit for non-residential uses, provided that the floor area occupied by residential use shall not exceed the floor area limit otherwise applicable to residential use. b. For a mixed-use structure with residential uses located on separate stories from non-residential uses, the floor area limits shall apply to each use at the applicable height limit. 4. Podium standards. The standards for podiums apply only to structures or portions of structures that include a tower that is subject to a floor area limit. a. Height limit for podiums. The specific podium height for a lot is shown on Map A for 23.48.245, and the height limit extends from the street lot line to the parallel alley lot line, or, where there is no alley lot line parallel to the street lot line, from the street lot line to a distance of 120 feet from the street lot line, or to the rear lot line, if the lot is less than 120 feet deep. If the street lot line is not straight, the measurement will be from the point where the distance between the street lot line and the rear lot line is the narrowest. The podium height is measured from the grade elevation at the street lot line. In the SM-SLU 85/65-160 and the SM-175/85-280 zones on the blocks bounded by Valley Street or Roy Street, Mercer Street, Dexter Avenue North, and Fairview Avenue North, the line on Map A for 23.48.245 demarcating the different podium heights within these blocks is located 120 feet north of the northerly line of Mercer Street. b. Podium floor area limits. For the podiums of structures with residential uses that exceed the base height limit established for the zone under subsection 23.48.225.A.1 the average gross floor area for all the stories below the podium height specified on Map A for 23.48.245 shall not exceed 75 percent of the lot area required for residential tower development, except that floor area is not limited for each story if the total number of stories below the podium height is three or fewer stories, or if the conditions in subsection 23.48.245.B.4.c apply. c. The floor area limit on podiums in subsection g does not apply if a lot includes one of the following: 1) Usable open space that meets the provisions of subsection 23.48.240.F; or 2) A structure that has been in existence prior to 1965 and the following conditions are met: a) The structure is rehabilitated and maintained to comply with applicable codes and shall have a minimum useful life of at least 50 years from the time that it was included on the lot with the project allowed to waive the podium area limit; b) The owner agrees that the structure shall not be significantly altered for at least 50 years from the time that it was included on the lot with the project allowed to waive the podium area limit. Significant alteration means the following: i. Alteration of the exterior facades of the structure, except alterations that restore the facades to their original condition; ii. Alteration of the floor-to-ceiling height of the street-level story, except alterations that restore the floor-to-ceiling height to its original condition; or iii. The addition of stories to the structure, unless the proposed addition is no taller than the maximum height to which the structure was originally built, or the addition is approved through the design review process as compatible with the original character of the structure and is necessary for adapting the structure to new uses; or c) If the structure is removed from the lot, then any use of the portion of the lot previously occupied by the structure shall be limited to usable open space. The portion of the lot previously occupied by the structure shall be defined by a rectangle enclosing the exterior walls of the structure as they existed at the time it was included on the lot with the project allowed to waive the podium area limit, with the rectangle extended to the nearest street frontage. d. Additional height for podiums abutting Class 1 Pedestrian Streets. Podium height for structures fronting on Class 1 Pedestrian Streets pursuant to Section 23.48.240 may exceed podium height limits shown on Map A for 23.48.245 by 5 feet provided that floor-to-ceiling clearance at the ground floor is at least 15 feet. 5. Aerial connections. Structures that use an additional increment of floor area provided in subsection 23.48.220.A.3.b may be connected by up to three aerial connections. The combined floor area in all aerial connections may not exceed 2,130 square feet and no one aerial connection may exceed 805 square feet. The floor area of aerial connections does not count toward the floor area limits of subsections 23.48.245.B.1 or 23.48.245.B.2. For purposes of this subsection 23.48.245.B.5, "aerial connections" are enclosed connections between structures that are located on the same block and that do not cross above public right-of-way. Map A for 23.48.245 Podium Heights C. Upper-level setbacks 1. The following requirements for upper-level setbacks in this subsection 23.48.245.C.1 apply to development that meets the following conditions: a. The development is on a lot abutting a street segment shown on Table A for 23.48.245; and b. For lots in the SM-SLU 85-280, SM-SLU 85/65-160, SM-SLU 175/85-280, and SM-SLU 240/125-440 zones located within the South Lake Union Regional Center, the development includes a tower structure with residential uses exceeding the base height limit established for residential uses in the zone under subsection 23.48.225.A.1, or includes a structure with nonresidential uses that exceed a height of 95 feet. 2. The required upper-level setbacks for development specified in subsection 23.48.245.C.1 shall be provided as follows: a. For portions of a structure facing the applicable street, the maximum height above which a setback is required is specified on Column 2 of Table A for 23.48.245. b. For portions of a structure exceeding the maximum height above which a setback is required, the minimum depth of the setback, measured from the abutting applicable street lot line, is specified on Column 3 of Table A for 23.48.245. Table A for 23.48.245 Required upper-level setbacks for development meeting the conditions of subsection 23.48.245.C Column 1: Location of lot Column 2: Height above which setback is required (in feet) Column 3: Minimum depth of setback from applicable street lot line (in feet) Thomas Street, south side, between Aurora Ave N to 8 th Ave N 45 50 Thomas Street, south side, between 8 th Ave N and 9 th Ave N 45 40 Thomas Street, south side, between 9 th Ave N and alley between Fairview Ave N and Minor Ave N 45 30 John Street, north side, between Aurora Ave N and 9 th Ave N 45 30 John Street, north side, between 9 th Ave N and Boren Ave N 45 15 John Street, south side, between Aurora Ave N and Minor Ave N 45 30 Boren Ave N, both sides, between Mercer Street and John Street 65 1 10 1 Fairview Ave N, west side, between Mercer Street and John Street 65 10 Fairview Ave N, east side, between Mercer Street to John Street 65 10 Footnotes to Table A for 23.48.245 1 On corner lots at intersections with Thomas and John Streets, for the portion of the lot subject to the setback requirements on these cross streets, the lower height above which setbacks are required and the greater distance of the setback from the cross streets apply. 3. Upper-level setbacks for residential tower development in the SM-SLU 85/65-160 zone on the blocks bounded by Valley Street, Mercer Street, Westlake Avenue North, and Fairview Avenue North. For tower structures that include residential use above the base height limit for residential use, or hotel use above a height of 85 feet, upper-level setbacks, in addition to those specified in subsection 23.48.235.B.1, are required as follows: a. Any portion of the structure above 65 feet in height shall set back a minimum of 30 feet from the following street lot lines: 1) The street lot line abutting the eastern edge of Westlake Avenue North from Mercer Street to Valley Street; and 2) The street lot line abutting the western edge of Fairview Avenue North from Mercer Street to Valley Street. b. For lots abutting the street lot line on the southern edge of Valley Street between Westlake Avenue North and Fairview Avenue North, any portion of a structure above 65 feet in height shall provide a minimum setback of 25 feet. 4. Upper-level setbacks for tower structures in the SM-SLU 175/85-280 zone for the block bounded by Mercer Street, Fairview Avenue North, Republican Street, and Boren Avenue North. In addition to upper-level setback requirements in this subsection 23.48.245.C, for tower structures with residential or non-residential uses on lots in the SM-SLU 175/85-280 zone on the block bounded by Mercer Street, Fairview Avenue North, Republican Street, and Boren Avenue North, any portion of the tower structure above 85 feet shall be set back a minimum of 110 feet from the street lot line abutting Mercer Street. 5. Projections permitted in required upper-level setbacks. The first 4 feet of horizontal projection of decks, balconies with open railings, eaves, cornices, and gutters are permitted in required setbacks, as shown in Exhibit B for 23.48.235 . D. Facade modulation. For all structures with non-residential uses exceeding 85 feet in height, facade modulation is required for the street-facing portions of a structure located within 15 feet of a street lot line and exceeding the podium height specified for the lot on Map A for 23.48.245. No modulation is required for portions of a facade set back 15 feet or more from a street lot line. 1. The maximum length of a facade without modulation is prescribed in Table B for 23.48.245. This maximum length shall be measured parallel to each street lot line, and shall apply to any portion of a facade, including projections such as balconies, that is located within 15 feet of street lot lines. Table B for 23.48.245 Facade modulation Height of street-facing portion of structure Maximum length of unmodulated facade within 15 feet of street lot line (in feet) For stories above the podium height specified on Map A for 23.48.245 up to 145 feet 150 For stories above 145 feet 120 2. If a portion of a facade that is within 15 feet of the street lot line is the maximum length permitted for an unmodulated facade, the length of the facade may be increased only if additional portions of the facade are set back a minimum of 15 feet from the street lot line for a minimum distance of 40 feet. If the required setback is provided, additional portions of the facade may be located within 15 feet of the street lot line. E. Maximum facade width. A maximum facade width applies to certain residential structures that exceed the base height limit for residential use, as specified in subsections 23.48.245.E.1, 23.48.245.E.2, and 23.48.245.E.3. The maximum facade width only applies to portions of the structure above the podium height specified for the lot on Map A for 23.48.245. 1. Except in the SM-SLU 100/65-145 zone and the SM-SLU 85/65-160 zone on the blocks bounded by Valley Street, Mercer Street, Westlake Avenue North, and Fairview Avenue North, for portions of a structure that exceed the podium height but do not exceed a height of 160 feet, and that have an average floor size exceeding 10,500 square feet, the maximum facade width is 120 feet along the general east/west axis of the site (perpendicular to the Avenues). 2. In the SM-SLU 100/65-145 zone, the maximum facade width is 105 feet along the general north/south axis of the site (parallel to the Avenues). 3. In the SM-SLU 85/65-160 zone, on the blocks bounded by Valley Street, Mercer Street, Westlake Avenue North, and Fairview Avenue North, the maximum facade width for portions of structures above the podium height is 105 feet along the general east/west axis of the site (perpendicular to the Avenues). F. Limit on towers per block or block front 1. For purposes of this subsection 23.48.245.F and subsection 23.48.245.G, a tower is considered to be "existing" and must be taken into consideration when other towers are proposed, under any of the following circumstances: a. The tower is physically present, except that a tower that is physically present is not considered "existing" if the owner of the lot where the tower is located has applied to the Director for a permit to demolish the tower and provided that no building permit for the proposed tower is issued until the demolition of the tower that is physically present has been completed; b. The tower is a proposed tower for which a complete application for a Master Use Permit or building permit has been submitted, provided that: 1) The application has not been withdrawn or cancelled without the tower having been constructed; and 2) 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 tower having been constructed. c. The tower is a proposed tower 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 tower as an existing tower 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 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. 2. Only one residential tower, or one tower with non-residential uses exceeding 85 feet in height, is permitted on a single block front, except as modified by subsections 23.48.245.F.3, 23.48.245.F.4, and 23.48.245.F.5. 3. In the SM-SLU 85/65-160 zone, only one residential tower structure or one non-residential tower structure with a hotel use meeting residential development standards is permitted per block. 4. In the SM-SLU 100/65-145 zone, more than one residential tower is permitted on a block front if the lot area is 30,000 square feet or more. 5. Only one tower with non-residential uses exceeding 85 feet in height is permitted on a block, unless the tower meets the requirements of Section 23.48.230 or unless all of the following conditions apply: a. The tower is on a lot with a minimum area of 60,000 square feet. The area of one or more lots, separated only by an alley, may be combined for the purposes of calculating the minimum required lot area under this subsection 23.48.245.F.5. The minimum lot area is 59,000 square feet if the lot area was reduced below 60,000 square feet as a result of acquisition of right-of-way by the City; b. A minimum separation of 60 feet is provided between all portions of structures on the lot that exceed the limit on podium height shown on Map A for 23.48.245. If the lot includes a qualifying Landmark structure, an average separation of 60 feet is permitted; c. A minimum of 15 percent of the lot area is provided as landscaped open space at ground level, allowing for some area to be provided above grade to adapt to topographic conditions, provided that such open space is accessible to people with disabilities. The required open space shall have a minimum horizontal dimension of 15 feet and shall be provided as one continuous area; d. A pedestrian connection meeting the development standards of subsection 23.48.240.H for through-block pedestrian connections for large lot developments is provided through the lot to connect the north/south avenues abutting the lot. If the lot abuts an avenue that has been vacated, the connection shall be to an easement providing public access along the original alignment of the avenue. In addition, if the slope of the lot between the north/south avenues exceeds a slope of ten percent, a hillclimb shall be provided; e. The application of the provisions in this subsection 23.48.245.F.5 shall not result in more than two structures on a block with either non-residential uses above 85 feet in height or with residential use above the base height limit for residential use, except as allowed by subsection 23.48.245.F.5.f; f. The block front on the east side of Terry Avenue North between Denny Way and Thomas Street shall be treated as two block fronts, separated by the location of John Street, if extended between Boren Avenue North and Terry Avenue North; g. The Director shall make a determination of project impacts on the need for pedestrian and bike facilities and complete a voluntary agreement between the property owner and the City to mitigate impacts, if any. The Director may consider the following as impact mitigation: 1) Pedestrian walkways on a lot, including through-block connections on through lots, where appropriate, to facilitate pedestrian circulation by connecting structures to each other and abutting streets; 2) Sidewalk improvements, including sidewalk widening, to accommodate increased pedestrian volumes and streetscape improvements that will enhance pedestrian comfort and safety; 3) Improvements to enhance the pedestrian environment, such as providing overhead weather protection, landscaping, and other streetscape improvements; and 4) Bike share stations; and h. For development that exceeds 85,000 or more gross square feet of floor area in office use, the Director shall make a determination as to the project's impact on the need for open space. The Director may limit floor area or allow floor area subject to conditions, which may include a voluntary agreement between the property owner and the City to mitigate impacts, if any. The Director shall take into account Section 23.48.250 in assessing the demand for open space generated by an office development in an area permitting high employment densities. 1) The Director may consider the following as mitigation for open space impacts: a) Open space provided on-site or off-site, consistent with the provisions in subsection 23.49.016.C, or provided through payment-in-lieu, consistent with subsection 23.49.016.D, except that in all cases the open space shall be located on a lot in an SM-SLU zone that is accessible to the development's occupants; b) Additional pedestrian amenities through on-site or streetscape improvements provided as mitigation for impacts on pedestrian facilities pursuant to subsection 23.48.245.F.5.g; and c) Public space inside or on the roof of a Landmark building. 2) The Director may approve open space in lieu of that contained or referred to in subsection 23.49.016.C to mitigate project impacts, based on consideration of relevant factors, including the following: a) The density or other characteristics of the workers anticipated to occupy the development compared to the presumed office employment population providing the basis for the open space standards applicable under Section 23.49.016 ; and b) Characteristics or features of the development that mitigate the anticipated open space impacts of workers or others using or occupying the project. 6. The block front on the east side of Terry Avenue N. between Denny Way and Thomas Street N. shall be treated as two block fronts, separated by the location of John Street N., if extended between Boren Avenue N. and Terry Avenue N. G. Tower separation. The following separation is required between a proposed tower with residential use above the base height limit for residential use and existing towers with residential use above the base height limit for residential use and that are located on the same block. For the purposes of this subsection 23.48.245.G, a block is defined as the area bounded by street lot lines and excluding alley lot lines. Alleys shall not be deemed to bisect a block into two separate blocks: 1. A separation of 60 feet is required between all portions of the structures above the podium height limit for towers that exceed the base height limit for residential use and any tower consider to be existing according to subsection 23.48.245.F.1. 2. No separation is required on blocks within the area bounded by Aurora Avenue North, John Street, Thomas Street, and 9 th Avenue North. 3. The first 4 feet of the horizontal projection of unenclosed decks and balconies, and architectural features such as cornices shall be disregarded in calculating tower separation. (Ord. 127375 , § 56, 2025; Ord. 126685 , § 29, 2022 [cross-reference update]; Ord. 126157 , § 32, 2020; Ord. 125927 , § 4, 2019; Ord. 125603 , § 37, 2018; Ord. 125291 , § 11, 2017; Ord. 125272 , § 35, 2017; Ord. 124883 , § 13, 2015.)