Common Residential Home Foundations

Bay Area residential foundation drilling

Homeowners don’t often think about the foundations of their home, but those foundations are critical components of any home, as they bear the entire load of the structure above. Foundations also have another critical function, in that they must prevent groundwater and soil vapors from penetrating into the home’s interior. When you’re trying to decide what kind of foundation your new home should have, there are four choices available to you, and each has advantages and disadvantages.

Choosing a Home Foundation


Basements are the most expensive option for installing your home’s foundation, but they also provide the most value. In the Bay Area, where land prices are extremely high, basements can add to the square footage of the home without increasing the homes’ overall footprint. Basements also can be finished for living space, and provide storage area. Basements are a good choice when cost isn’t a big issue, but in locations where the water table runs high, they may not be a good option.


Slabs are probably the most common type of foundation in California, a by-product of their simplicity and cost. Slab foundations require less maintenance than any other type of foundation, however they do have drawbacks. Earthquakes and expansive soils, of which there is a lot in the San Francisco Bay Area, can cause foundation slabs to crack. This remains an issue with slabs, although in recent years cracking issues have been mitigated by with the use of Post Tension cables within the slabs. Slabs can be used when the ground is fairly level, but any kind of sloping character to the building lot could make installing a slab less advantageous.


A crawlspace foundation is can be another solution, in place of or in combination with a slab. Footings have to be poured, and then cinder blocks are situated on top of those to support for the home’s walls. With a crawlspace foundation, it is typically positioned a few feet above the ground, leaving an opening underneath the structure.

Since plumbing is not buried like it would be under a slab, repairs can be made more easily, and since the crawlspace enclosure includes conditioned air, it won’t feel as chilly or as warm in the home directly above. Crawlspaces also provide protection against moisture entering the home. In terms of cost, crawlspaces are more expensive than slabs, but less expensive than installing a full basement.

Pier and Beam

As the name suggests, a complex of drilled piers and beams support your home. Piers are drilled down into the soil to rest on solid rock, and the piers support beams that support the house. The big advantage is that the house is less likely to shift around as a result of movement in the soil directly underneath of your home. This type of foundation is more expensive than a concrete slab, but offers more solid long-term support.

Foundation Excavation Experts

Lassiter Excavating works with general contractors throughout Northern California in preparing sites properly for foundation construction. Our services include both excavating and pier and pile drilling. Contact us to discuss your projects in more detail.