We get all kinds of good search words driving traffic to theFrontSteps, but “MonsterTruck” still leads the pack for consistency. Recently we had quite a few people find the site searching “Bedrock SF” and more specifically “Is the Infinity condo sf built on bedrock”? For exact details, we’d suggest you contact the folks at the Infinity directly, but should you care to browse some of the bedrock maps we alluded to previously, by all means, don’t let us stop you.


From what we can tell, the Infinity is located on the block where Folsom and Spear intersect (highlighted in green circle) and there is a chance it is built on a little bit of both (landfill and bedrock). We would still suggest you consult the experts.

[Update: From “Henry” who makes an excellent point, “It doesn’t matter. Any building that size will have piers all the way down to bedrock, even if the material above it is landfill.”]

Ask Us: A Map of Bedrock vs. Landfill (SF) [theFrontSteps]

USGS Seismic Site
Liquefaction Zones of San Francisco’s Marina District [theFrontSteps]

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  1. It doesn’t matter. Any building that size will have piers all the way down to bedrock, even if the material above it is landfill.

  2. If you remember, there were articles when they dug the foundation that they found a ship wrecking yard on the site. I believe this was in the SFChron. But, the major ship they found was half under the site and half under Folsom street and they left that half there. So, this block was right on the waterfront and would probably just catch the edge of the bedrock. I would agree with Henry though, the piers and foundation here were sufficiently engineered to support well more than the development.

  3. In some instances ( and I don’t believe this is the case with the infinity) they will use piers that go down several hundred feet without reaching bedrock. These piers are sometimes designed to hold up the building by friction between the pier and the soil they are pounded down into.

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