Mercer Island Parks commission narrows park-zone rules on signs, scoreboards, impervious surface and building size

Mercer Island Parks and Recreation Commission members reviewed and largely endorsed a package of draft park‑zone development regulations on March 6, 2025, after staff presented follow‑up recommendations and examples for signs, scoreboards, impervious surface exemptions and new building‑size standards.

The discussion, held during the commission’s regular meeting at the Mercer Island Community and Events Center and on Zoom, focused on balancing long‑term park stewardship with practical needs for restrooms, maintenance storage and recreation support structures. Carson Hornsby, management analyst for the city, told commissioners the staff recommendation was “a limit of 16 square feet” for general park signs and that the one outlier at Mercerdale would be treated as nonconforming and reduced if replaced.

Commissioners heard staff proposals for scoreboards, including a 250‑square‑foot size limit designed to encompass the Island Crest Park scoreboard and lettering, and for permitting electronic and externally lit scoreboards. Commissioner Markson asked about caps on the number of scoreboards per park; Hornsby said the current draft does not set a per‑park scoreboard count.

Why this matters: the draft park zone is intended to protect open space character while allowing routine park operations and upgrades. Commissioners repeatedly raised the challenge of writing rules that keep parks from becoming over‑built yet still allow functional facilities such as restrooms, storage and small support buildings.

Key decisions and consensus points

- Signs: commissioners gave staff a thumbs‑up for a 16‑square‑foot maximum for standard park signs; the larger Mercerdale sign would remain nonconforming until replaced. (Staff: Carson Hornsby.)

- Scoreboards: commissioners approved staff’s recommendation of a 250‑square‑foot maximum and agreed electronic and externally lit scoreboards can be allowed under the draft regulations.

- Impervious surface exemptions: the commission preserved an exemption for required playground surfacing but refined the scope. After discussion, commissioners agreed to exempt required surfacing immediately surrounding playground equipment — including fall zones and surfaces needed to meet accessibility — rather than treating entire playground parcels as exempt.

- Small park amenities: the commission agreed to define “small amenities” that are exempt from impervious‑surface limits as individual features up to 100 square feet (examples in the packet include benches, trash cans, small concrete pads). Commissioners also kept examples in the draft to guide application.

- Emergency work: staff removed the word “construction” and the commission agreed to exempt “emergency repairs or maintenance” (e.g., emergency shoring, temporary stabilization, urgent utility work) from the impervious‑surface limit; staff confirmed normal permitting processes and public‑safety limits still apply.

- Lighting: staff removed an unnecessary exemption for lighting in rights of way; lighting rules in the draft remain focused on minimizing glare, sky glow and trespass.

- Building size standards: commissioners accepted staff’s approach to regulate existing and new park buildings with a set of size limits and tailored exemptions rather than a blanket exemption for existing buildings. The agreed‑upon thresholds in the draft are: stand‑alone restroom, park maintenance, and small recreational facility buildings not to exceed 500 square feet gross floor area; picnic shelters up to 1,200 square feet and 16 feet in height (previously agreed); multipurpose buildings (those that combine uses such as restrooms, concessions and storage) capped at 3,500 square feet gross floor area. Staff noted the batting cage at Island Crest Park is about 2,450 square feet and the Island Crest multipurpose building is just under 3,500 square feet, which helped set that upper bound. Commissioners asked staff to return with a proposal to bound heights so existing tall structures are accommodated but multi‑story expansion is limited.

Debate over Luther Burbank buildings and ‘government services’ language

Commissioners discussed whether to exempt three specific Luther Burbank Park buildings (administrative building, boiler building and caretaker’s residence) from the size limits and whether to list “government services” as an allowed use there. Jesse Bond, city manager, explained staff’s preference for flexibility because the city currently relies on those facilities to house municipal functions while a long‑term facilities plan is unresolved.

Several commissioners expressed discomfort embedding a broad “government services” allowance in park code; others acknowledged current operational constraints. The transcript records extended discussion and staff agreed to narrow the code language to “City of Mercer Island government services” and to clarify the exemption language before the next meeting. The commission did not record a formal roll‑call vote removing the exemptions; staff will return with revised language in April.

Next steps and context

Staff will revise the draft language to clarify playground surfacing language, refine the small‑amenity examples and propose a measured height limit that fits the current building inventory. The GIS‑based draft zoning map was presented and commissioners signaled tentative support; staff will finalize map details and bring a revised handoff memo and code language back to the commission at the April meeting for a final review before transmittal to council.

Quotes

“We had a very last minute change on the section and the draft code on buildings... we forgot to put her back on last week for a final review,” City Manager Jesse Bond said, explaining last‑minute edits from outside counsel.

“We are proposing a new recommendation of 250 square feet,” Carson Hornsby said about scoreboards, “which encompasses that entire scoreboard, including the lettering.”

“I think it would be hard to put a cap on this because I recall with Mercerdale, the number of benches that were put into place became part of the design element,” Commissioner Hay said while arguing against a strict numeric cap on amenities.

“I'd encourage you to maybe think a little bit more on that one and see if you can sharpen the definitions,” Councilmember Reynolds said, urging staff to clarify terms such as “surrounding” and “play equipment.”

Ending

Staff will bring revised code text and a height‑limit proposal to the April 3, 2025, commission meeting. The commission instructed staff to tighten definitions and return with clearer language on playground surfacing, small amenities, emergency repairs and the limited exemptions for specific Luther Burbank buildings.