Structure height
Seattle Mun. Code § 23.48.025
in effectA. Height limits 1. The height limits for structures in Seattle Mixed zones are as shown on the Official Land Use Map, Chapter 23.32 , except as otherwise provided in this Section 23.48.025 or in the applicable subchapters of this Chapter 23.48 for Seattle Mixed zone designations for specific geographic areas shown in Table A for 23.48.002. In certain zones, as specified in this Section 23.48.025 , the maximum structure height is allowed only for particular uses or only under specified conditions, or both. Where height limits are established for portions of a structure that contain specified types of uses, the applicable height limit for the structure is the highest applicable height limit for the types of uses in the structure, unless otherwise specified. 2. In the SM-SLU and SM-D zones, the applicable height limit for portions of a structure that contain non-residential and live-work uses is shown as the first figure after the zone designation, and the base height limit for portions of a structure in residential use is shown as the first figure following the "/". The third figure shown is the maximum residential height limit. B. Pitched roofs. In SM zones with a height limit of 85 feet or less, the ridge of a pitched roof with a minimum slope of 6 to 12 may extend 10 feet above the height limit. The ridge of a pitched roof with a minimum slope of 4 to 12 may extend 5 feet above the height limit (Exhibit A for 23.48.025). No portion of a shed roof shall be permitted to extend beyond the height limit under this provision, 23.48.025 . Exhibit A for 23.48.025 Pitched Roofs C. Rooftop features 1. Smokestacks, chimneys, flagpoles, and religious symbols for religious institutions are exempt from height controls, except as regulated in Chapter 23.64 , provided they are a minimum of 10 feet from any side or rear lot line. 2. Open railings, planters, skylights, clerestories, greenhouses, parapets, and firewalls may extend up to 4 feet above the maximum height limit with unlimited rooftop coverage. Insulation material or soil for landscaping located above the structural roof surface may exceed the maximum height limit if enclosed by parapets or walls that comply with this subsection 23.48.025.C.2. 3. Solar collectors may extend up to 7 feet above the maximum height limit, with unlimited rooftop coverage. 4. The following rooftop features may extend up to 15 feet above the applicable height limit, if the combined total coverage of all features listed in this subsection 23.48.025.C.4 does not exceed 35 percent of the roof area, or does not exceed 60 percent coverage of the roof area if the total includes a greenhouse: a. Solar collectors that exceed heights allowed by subsection 23.48.025.C.3; b. Stair and elevator penthouses; c. Mechanical equipment; d. Atriums, greenhouses, and solariums; e. Play equipment and open-mesh fencing that encloses it, as long as the fencing is at least 15 feet from the roof edge; f. Minor communication utilities and accessory communication devices, except that height is regulated according to the provisions of Section 23.57.012 ; g. Covered or enclosed common amenity area; h. Chimneys; i. Sun and wind screens, and similar weather protection features such as eaves or canopies extending from rooftop features; and j. Wind-driven power generators. 5. For structures greater than 85 feet in height, elevator penthouses up to 25 feet above the height limit are permitted. If the elevator provides access to a rooftop designed to provide usable open space or common recreation area, elevator penthouses and mechanical equipment up to 45 feet above the height limit are permitted, provided that all of the following are satisfied: a. The structure must be greater than 125 feet in height; and b. The combined total coverage of all features gaining additional height listed in subsection 23.48.025.C.4 does not exceed limits listed in subsection 23.48.025.C.4, or the limit in subsection 23.48.025.C.6 if it applies. 6. At the applicant's option, the combined total coverage limit of all rooftop features listed in subsections 23.48.025.C.4 and 23.48.025.C.5 is 75 percent, provided that all of the following are satisfied: a. All mechanical equipment is screened or enclosed; and b. No rooftop features are located closer than 10 feet to the roof edge, except features that do not exceed the height of the parapet or 5 feet above the roof surface, whichever is greater, or which may be permitted by design review departure or other code provisions including but not limited to Chapter 23.57 . 7. In order to protect solar access for property to the north, the applicant shall either locate the rooftop features listed in this subsection 23.48.025.C.7 at least 10 feet from the north lot line, or provide shadow diagrams to demonstrate that the proposed location of such rooftop features would shade property to the north on January 21 at noon no more than would a structure built to maximum permitted bulk: a. Solar collectors; b. Planters; c. Clerestories; d. Atriums, greenhouses, and solariums; e. Minor communication utilities and accessory communication devices according to the provisions of Section 23.57.012 ; f. Sun and wind screens, and similar weather protection features such as eaves or canopies extending from rooftop features; g. Nonfirewall parapets; h. Play equipment; and i. Covered or enclosed common amenity areas. 8. Screening. Rooftop mechanical equipment and elevator penthouses shall be screened with fencing, wall enclosures, or other structures. 9. For height limits and exceptions for communication utilities and accessory communication devices, see Section 23.57.012 . (Ord. 126600 , § 7, 2022; Ord. 126157 , § 29, 2020; Ord. 125791 , § 58, 2019; Ord. 125272 , § 32, 2017; Ord. 125267 , § 20, 2017; Ord. 124883 , § 13, 2015.)
Source: Seattle Municipal Code (Municode library)URL: https://library.municode.com/wa/seattle/codes/municipal_codeFetched: 7/25/2026