Voluntary Homeowner Seismic Safety Initiative

by John Frando

Just after 5 p.m. on October 17, 1989, Laurel resident Libby Jacobsohn was at home when a magnitude 7.1 earthquake, centered over 70 miles away near Loma Prieta Peak in the Santa Cruz Mountains, cracked the chimney and the foundation in seven locations under her nearly 70-year-old house.

Husband Jerry remembered that night. They slept in sleeping bags in the backyard.

When Libby and Jerry hired a contractor to replace the chimney and repair the foundation, they went further by having him nail plywood panels to the stud framing (or cripple walls) in the crawl space under the house, connect the underside of the floor joists to the cripple-wall top plates with metal hurricane clips, and set additional anchor bolts through the mud sill into the rebuilt concrete footings.

After the earthquake, Jerry learned these basic house retrofitting measures at a homeowner's learning center in Berkeley. His goal was to diminish the possibility that in the next catastrophic earthquake the cripple walls under the house would collapse and that the house would slide off its foundation.

The US Geological Service warns of a 62 probability of a magnitude 6.7 earthquake in the Bay Area by 2032. Should it occur along the Hayward fault, one third of homes in Oakland are expected to be lost. Eighty-five percent of existing homes in the city, built before modern building construction codes, lack strengthening offered by the simple measures Libby and Jerry took.

To motivate owners of older houses to retrofit their homes, Councilmember Jean Quan's office authored the Homeowner Voluntary Seismic Safety Incentive Ordinance. Passed July 3, 2007, it created Chapter 15.30 in the city's Municipal Code. 15.30 incorporates basic retrofit standards into the code, establishes a flat retrofit permit fee of $250 for one- to two-story houses or duplexes, and launches an incentive program allowing new owners of older homes a reimbursement of up to $5,000 of their retrofitting costs.

Retrofitting Standards

Owners of houses meeting certain physical criteria can be issued a permit without engineered calculations or drawings if they follow carefully the Prescriptive Design measures defined in Plan Set A, downloadable construction drawings from the website of the Association of Bay Area Governments (ABAG).

Owners of homes excluded from using Plan Set A (causes include building height, building size, steep lot slope, discontinuous foundation footings or poles or columns embedded in the ground such as in hillside homes) or homeowners wanting to exceed the Prescribed Design measures must follow the "Non-Prescriptive Design" approach, which requires specially engineered calculations and prepared drawings.

The first critical step in applying for a permit is to meet with a building department official to determine the appropriate approach. Bring photographs of the house exterior and rough overall measurements.

Flat Permit Fee

There is now a flat $250 retrofit permit fee for all owners of one- or two-story houses or duplexes complying with the city's retrofitting standards. Prior to the passage of the ordinance, permit fees were 10 of the total costs to retrofit–both materials and labor costs. Some homeowners reported paying as high as $3,000 in permit fees.

New Owners Incentive Plan

Owners of non-retrofitted residences who recorded the transfer of ownership within 60 days of July 5, 2007, may apply for City reimbursement of up to half a percent of the home purchase price, or $5,000 (whichever is less), to cover retrofitting costs. After applying, they have one year to complete the work.

Seismic retrofitting of existing houses is not mandatory. Sue Piper of Councilmember Quan's office cited a 2006 University of Buffalo study in which a two-story wood framed house, built to California earthquake standards and then shaken in a simulated 6.7 earthquake, survived with little structural damage.

"It's not only about saving lives," she said "but as we see in post-Katrina New Orleans, cities have to consider the short- and long-term social and economic effects of temporary and permanent evacuations of residents."

Resources

Download the Home Seismic Strengthening Initiative document (outlining Ch. 15.30 of the City Municipal Code) at www.Oaklandnet.com. Or contact the Oakland Building Department at 238-3891, or email Jim Oakley at joeoakley\@oaklandnet.com.

Download Plan Set A at the Association of Bay Area Government's website at http://quake.abag.ca.gov/fixit/.

For general disaster-preparedness information, visit www.72hours.org.

Councilmember Quan will discuss retrofitting and the new ordinance at an October 3 meeting, 6 p.m. – 8 p.m. at the Oakland Association of Realtors offices, 1528 Webster Street. Seating is limited to 75 people.

John Frando can be reached at jfrando\@gmail.com.