This post has been coming for a long time, and on this topic I want to be really clear. 1) foundation problems are common in Foster City and 2) those foundation problems are not a reason to avoid purchasing a home in Foster City. For several years, many many homes have had issues with their foundations in this area. I met an engineer once who told me that he had fixed 60 foundations in Foster City over the years. I’m not an engineer, but as I understand it the majority of issues come from exposed rebar that’s rusted over time, has expanded and then cracks or breaks up the concrete around it. I’ve also heard that the high sodium content in the Foster City landfill impacts this rusting problem a bunch. The photo above is a typical example. The pieces on the right have fallen away from the rest of the foundation and the rusted rebar is obvious. The weakened condition of a foundation with this type of problem theoretically has an adverse effect on it’s seismic stability.

Several contractors or engineers have made a good business out of resolving these issues. The fix on the foundation pictured above is slightly under $24,000. If you’re looking at a hillside property in San Mateo, Belmont or San Carlos you could easily find drainage issues that can have similar expense and that certainly doesn’t prevent people from buying homes in those locations. Foundation problems in Foster City are correctable and shouldn’t frighten anyone out of buying here.

It is wise, however, for a buyer to be diligent in inspecting the home they are purchasing…and that means hiring an engineer or qualified foundation contractor (one who has experience with this type of issue in Foster City is best) to inspect this area. Most property inspections will note rusted rebar if found but not go any further in explaining a solution for it. Be proactive, if there’s even a hint of a problem on a report get further inspection.

I think there isn’t a subject that comes up about Foster City as commonly as the subject of Landfill does. The town was essentially created in the early 1960’s from the marshland that was Brewer’s Island and 14 million cubic yards of material were deposited there to create the basis of what now is Foster City. On all of the standard disclosures a buyer will see, no matter where they buy, are mandatory geological reports that designate, among other things, an area’s “liquefaction potential”. Historic evidence has suggested that landfill on Bay mud is a danger of liquefying and every few years the U.S. Geological survey releases regional earthquake hazard maps that highlight areas they see as worry-some. The last one in 2006 labeled Foster City as “high risk”. Consequently folks tend to get concerned and Foster City has always had some kind of stigma as a result. What’s always confused me is that I tend to not hear so much concern about the large areas of San Mateo that are fill as well as Redwood Shores, which is just like Foster City. The fact is that in 1906, 1989 and 20 other earthquakes throughout the region which covers 9 counties and 180 cities, the chance of liquefaction-the result of a shake so hard that water and sand mix together and become sandy liquid-is one instance per every 1.5 miles. That puts Foster City at a chance for 2 or 3 instances. There were 3 documented instances in Foster City in 1989 and they were small. I’ve heard it said that there were less insurance claims made in Foster City in 1989 than in most other outlying, non landfill areas. It’s also been commonly reported that the engineered landfill that was done in the 60’s when Foster City was created made a huge difference in it’s durability and stability during an earthquake. The USGS maps do not take into account any difference between the type of fill in San Francisco’s Marina District, for example, and Foster City’s engineered fill. Here’s a link to the City’s website and their perspective on landfill in this area:

LandfillLink