Mill Valley to mandate quake retrofitting for some buildings

Oct 11, 2023

Mill Valley will require earthquake retrofitting for some apartment buildings built before 1978.

The City Council unanimously approved the ordinance on Monday. The second reading is expected on June 26.

Planning Director Patrick Kelly said the upgrades are intended to ensure the housing stock is protected from the risk of collapse during quakes.

The ordinance applies to "soft-story" apartment buildings, or those with a wood-frame target story design and three or more residences. Approximately 50 to 90 buildings could meet the criteria, said David Bonowitz, the city's contract structural engineer. The buildings contain about 250 to 500 apartments, or about 4% to 8% of the city's housing stock.

Collapsed homes have the potential to destroy plumbing and start gas fires, Bonowitz said.

A licensed architect or civil engineer would screen the buildings to determine eligibility.

If a building is not exempt, a licensed architect or civil engineer would design a retrofit, present the findings to the building department and obtain a permit for construction.

Wood-frame target story buildings typically have a ground story or foundation crawl space with wood frame walls and partitions. The deadlines are broken into three tiers.

The owners of any building with an occupied space in the story with the wood framing — defined as the "critical story" — will have five years to acquire a retrofit permit and six years for construction.

The next tier involves buildings in high landslide risk areas. The property owners will have four years to acquire the permit and five years for construction.

The owners of all other buildings will have two years to get the permit and three years to perform construction.

The deadlines are meant to allow time to secure funding for the projects.

The Marin Housing Authority offers a rehabilitation loan program that might be used for the soft-story retrofit of relatively small owner-occupied buildings. State and federal grants are considered limited. A state program has not been confirmed under the current budget, and if it is, it would be focused on affordable housing and disadvantaged owners and tenants, according to a staff report.

The preliminary cost estimate for a two-, three- or four-story building ranges from $35,000 to $70,000. For larger buildings, the estimate is between $40,000 and $130,000.

Planning officials first proposed the program in 2021. In May 2022, Bonowitz presented the plan to the council, which signaled support for a program for buildings with three or more rental apartments.

Renter protections are built into the ordinance.

"Completing this job is not just cause for eviction," Bonowitz said.

The ordinance is expected to go into effect on Dec. 15, setting off a city program to identify buildings that will require the retrofit. Notification to building owners is planned by March. A screening deadline is tentatively set for one year after the ordinance goes into effect.

"I think this is a no-brainer for us," said Councilmember Max Perrey. "At the end of the day a big component of earthquake safety is the building side."

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