Planning commission approves Wonder House coworking and family‑oriented amenities at 55 Sunnyside

The Mill Valley Planning Commission on Feb. 10 approved a conditional use permit for a downtown coworking business called Wonder House at 55 Sunnyside Avenue, granting the applicants permission to operate extended hours and program occasional events with conditions aimed at minimizing neighborhood impacts.

Senior planner Steve Ross told the commission the proposal is to reactivate a historic 1940 post office building for a coworking use with ‘family oriented amenities and occasional special events.’ He said the building has about 7,000 square feet and 18 parking spaces and that staff recommended the project be found categorically exempt from CEQA and approved pursuant to the listed findings, with one inadvertent survey requirement removed from the proposed conditions.

The commission’s approval allows daily hours from 7 a.m. to 10 p.m., an extension beyond the standard 8 a.m.–8 p.m. limit that triggered the CUP review. Ross said a key condition prohibits alcohol service and entertainment and requires compliance with the city’s good‑neighbor policies to reduce noise and impacts from users arriving and leaving via the rear parking area. He noted staff received a mix of correspondence — “I think 7 emails of support” — and one or more emails expressing concerns about hours and noise.

Applicant Jennifer Zheny, who identified herself as a Mill Valley resident and educator, described Wonder House as “a thoughtfully designed place for people of all ages where parents can focus on meaningful work without sacrificing time and connection with their children.” She said the model relies on short, rotating visits rather than long‑term desk leases and emphasized that guardians must remain on site when children are present.

Neighbors at the hearing raised concerns about off‑hours activity in the rear parking lot. One nearby resident, who said she lives at 57 Sunnyside, recounted past late‑night problems at the vacant lot and asked how the applicant would secure the parking area and limit outside congregation. “Drag racing was happening at 2AM on a Saturday night,” she said, and later asked how construction impacts, party sizes and event frequency would be limited.

Commissioners discussed enforcement options and possible limits on event frequency but generally supported staff’s recommended conditions and the applicant’s operational safeguards, including interior noise mitigation and signage at exits. Commissioner Scouse moved to approve the CUP with the staff edits (deleting the survey condition); the motion was seconded and carried on a unanimous voice vote.

The commission’s action includes the standard appeal instructions: decisions may be appealed to the Mill Valley City Council within 10 calendar days of the decision by filing a letter with the planning and building department and paying the required fee.

The permit includes explicit conditions: hours limited to 7 a.m.–10 p.m. daily, prohibition on alcohol service without a separate CUP process, adherence to good‑neighbor policies on noise and management responsibility for responding to complaints. Staff noted that enforcement would depend on complaint investigation and code enforcement if problems arise.

The commission’s approval means the applicants may proceed with the tenant improvements and building‑permit process; any future request to serve alcohol or change conditions would likely require additional review and findings.

Votes at a glance: The commission approved the conditional use permit for 55 Sunnyside Avenue by a unanimous roll call vote of the three commissioners present.

Next steps: The applicants will pursue building permits and any required historic‑building compliance work; neighbors retain the right to appeal the decision within 10 days.