What does a Geotechnical Engineer do?
Anything having to do with knowing things about or construction that happens below the surface of the ground requires a geotechnical report. That’s the “Geo” part. Engineering means Design.
Let’s say that you are putting an addition on your home. In order to properly design the concrete foundation, the Structural Engineer needs to know what kind of soil conditions the new foundation will be installed on. Is it beach sand (like the sunset district in SF)? Is it solid rock (like some locations in the Tiburon hills)? Or something in between? The answer to these questions are supplied in a Soils Report by a Geotechnical Engineer and will have a profound impact on the design and long-term stability of your addition. In addition, many cities (and structural engineers) may require these reports as part of the overall package for permit submittal.
That’s one instance, and probably the most common for residential construction work done in the Bay Area.
As is also common for our area, many properties are on steep hillsides and the big question on many homeowner’s minds is “Is it stable, or could it come tumbling down in a heavy rain or earthquake?” The Geotechnical Engineer can detect slip planes and other soil conditions and answer that question with as much exactitude as possible.
If you have a failing septic system, it’s the Geotech who will design a solution based on test holes and other data. Likewise, you’ll need the Geotech’s assistance in finding the best location for your water well.
If you have a water management or site drainage issue, the Geotech may be invaluable in designing a solution to keep the soil around your foundation drained so that your home does not settle and degrade your investment in it.
Many owners are opting for a new driveway using pavers instead of concrete or asphalt. Pavers sit on sand which sits on top of a “road base” of some sort, which in turns sits on the ground and the whole thing may need drainage elements to ensure it’s long-term integrity. Proper soil compaction is also key for long term stability.
The need for (and how much) compaction, the depth of the road base, what kind of base to use, the thickness of the sand, and the configuration of the drainage elements are all specified and designed by the Geotechnical Engineer.
They do much more, but those are the highlights for residential construction in the Bay Area. What’s also important to understand is that the Geotech is usually part of a team of specialists hired and coordinated by the General Contractor or the Architect (one in the same in a Design-Build firm). It’s important that their input is considered in context along with the input from the entire design and building team to make sure your investment dollars are well-spent.
Got a question about your home? Here’s your chance to ask the “Design-Build Advisor!” Give us a call at 415-459-3349 or send your question to john@theperfectbuilder and we’ll answer
either in this blog or by e-mail.