Planning Commission refines rules for temporary uses; approves large deviation criteria for country‑club bubble and schedules second public hearing

The Mercer Island Planning Commission on July 23 adopted multiple amendments to the draft code governing temporary uses and structures and revised a new deviation standard that will allow larger temporary structures in residential zones when the city finds a substantial public benefit. The session focused on a pending application and precedent set by a large “tennis bubble” at Mercer Island Country Club and ended with the commission directing staff to prepare a final draft for a second public hearing on Sept. 10.

Deputy CPD Director Lisonbee Van Gorp and Senior Planner Molly Maguire led the staff presentation and recapped the procedural history: an interim regulation was previously adopted and the commission began a public hearing process on June 10; staff restructured the draft to a tiered permit approach (exemptions, normal temporary uses, and deviation approvals) and returned with a set of staff‑ and commissioner‑proposed amendments. Maguire summarized the bucketed approach and the recommended review types (type 2 for normal temporary uses, type 3 for deviations, with renewal provisions and expiration rules).

Major outcomes and votes: - The commission voted to accept the “category A” amendments (consensus items from June 10) and the “category B” staff consistency amendments. - Vice Chair Gibson moved and the commission adopted a replacement for the draft’s new section F (deviations for temporary structures on private property). The approved F text raises the thresholds for large public‑benefit deviations: the maximum permitted temporary structure occupancy threshold in the vice‑chair’s replacement increased from 50 to 250 people for qualifying public‑benefit uses; maximum temporary gross floor area for a deviation was increased from 10% to 20% of lot area; maximum temporary lot coverage allowance was increased from 5% to 10% of lot area; and yard setbacks were limited to a minimum of 4 feet (the replacement also removed a clause requiring the temporary use to be accessory to the established use of the property). - The commission deleted a discretionary 30‑day extension from the draft’s time‑limit provision so that the code now limits temporary structures to 180 days per year without an administrative extension (the motion passed 4–1). - The commission adopted procedural clarifications including renewal and expiration rules for type‑2 and type‑3 permits and moved a set of minor, staff‑recommended edits. - The commission added an exemption for temporary structures used for worship (e.g., sukkahs) up to specified size and time limits, and voted to remove an explicit prohibition on amplified sound from the exemption language. - The commission voted to table the main recommendation until staff prepares a final draft for a second public hearing on Sept. 10; staff and the city attorney advised that, given the scope of changes made since June 10, a second hearing is appropriate.

Context and technical clarifications discussed in the meeting: - Staff explained the Country Club’s existing permitted building is approximately 18,600 square feet and the tennis bubble’s footprint was cited in permit documents as about 23,800 square feet; converting a hardscape tennis court to a roofed structure changes how area is counted for lot‑coverage and gross‑floor‑area calculations (e.g., high ceilings can count double under local GFA rules). Maguire said that because the bubble converts an existing hardscape to roofed lot coverage, the permitted temporary lot‑coverage allowance would need to be larger than the 5% initially proposed and staff suggested 10% or more to accommodate the Country Club example. - Commissioners and staff discussed screening requirements for deviations (vegetative or fence screening) and whether the code should include objective metrics; staff said screening may be temporary or permanent and that proportionality between the degree of deviation and screening was an objective. - Commissioners asked whether fire‑ and building‑code separations and easements played into what could be approved; staff confirmed building and fire codes remain applicable and that some of the Country Club’s ability to site its bubble was related to a required separation to adjacent structures and agreements with adjacent owners.

Clarifying numbers recorded in the discussion: the bubble footprint was cited as ~23,800 sq. ft.; the existing main building ~18,600 sq. ft.; staff described a lot‑coverage figure in permit documents as "around a 165,000 square feet" (per staff permit records cited in the meeting); the draft allowed temporary structures up to 180 days per calendar year (the commission removed a 30‑day administrative extension); yard setbacks cited for the Country Club encroachment included about 4.25 feet into the rear yard per existing permits. The vice‑chair’s replacement text specified minimum setbacks of 4 feet, increased GFA/coverage allowances (20% GFA, 10% lot coverage), and raised the qualifying occupant threshold for significant public‑benefit uses to 250 people.

What’s next: staff and the city attorney told the commission that because the draft has changed substantially following June 10 and additional edits were made July 23, the public should have an opportunity to review the updated package; staff recommended and the commission agreed to a second public hearing on Sept. 10. The commission tabled its main recommendation until that hearing and asked staff to prepare a consolidated packet reflecting the July 23 changes.