San Francisco’s propensity for shaking by earthquakes makes it a less-than-ideal place for unreinforced brick and masonry structures. With their many built-in fault lines, buildings made of brick, adobe, stone, clay tile or other kinds of masonry can easily shift and topple in a major quake. Because of these hazards, builders now construct homes with reinforced materials that can withstand lateral seismic movement. However, given the age of the City, many older brick and masonry structures still dot the landscape. Perhaps you even call one home.

If so, what can you do to seismically strengthen an older house? Seismic strengthening involves shoring up structural weak points such as deteriorating masonry and unanchored walls. Structural retrofits of this sort can be costly and should be designed by a licensed engineer or architect who has inspected and assessed the current condition of your home. The minimum standard applied to the seismic strengthening of most unreinforced brick and masonry buildings is “Bolts Plus,” a level of retrofitting that involves anchoring the walls to the floors and roof, as well as installing wall supports to reduce out-of-plane failures. However, the specific requirements for your own home could be more elaborate.

If you have recently purchased a house in San Francisco, the seller should have disclosed any seismic weaknesses in the structure. Your inspector should also have uncovered any potential hazards. But iIf you are still unsure of the condition of your home, it is advisable to call in an engineer experienced in seismic safety to perform an inspection.