Drilled Caissons for Hillside Homes in LA: Depth, Rock, Access and What Drives the Cost

On a hillside lot in Los Angeles, the foundation for a new home, addition or pool often sits on drilled caissons: concrete shafts reinforced with steel cages, drilled down until they reach the support the geologist and structural engineer call for. These are the things that drive the schedule and the budget.

The design comes first

The Engineer of Record designs the caissons: diameter, depth, reinforcing and how they tie into the grade beams. The soils report sets the geologist's minimum embedment, the depth into competent material each shaft has to reach. We build what the plans show, as the contractor's means and methods.

What drives depth and time

• The minimum embedment. Every shaft has to reach the geologist's minimum, and the geologist can call for more depth in the field if the material isn't what was expected.
• Rock. Rock drills far slower than soil. Where augers stop, we switch to a coring bucket with water and, where needed, a man-entry method to break out the core. Rock is the single biggest swing in a caisson schedule.
• Caving ground. In loose soil, a shaft can cave before it is poured. We drill, set the cage and pour the same day, or case the hole when the plans call for it.
• Access. Narrow canyon streets and tight lots limit how big a rig can reach the site. Our own compact rig fits where full-size rigs can't.
• Spoils. Every foot drilled comes out as soil or rock that has to be hauled off.

Why budgets come in depth scenarios

Nobody knows exactly how deep every shaft will go until it is drilled. So we price caissons in depth scenarios keyed to the geologist's minimums, instead of pretending to know the final depth. That way the budget is honest about the one thing neither the owner nor the contractor can control, and over-depth is handled by an agreed method, not an argument.

Inspection before concrete

The geologist checks each shaft before concrete goes in, to confirm it reached the material and depth the design requires. After that, the cage goes in and the shaft is poured.

Shoring on the same lot

Many hillside projects also need temporary shoring to excavate safely next to a slope, a street or a neighbor. Shoring is built to a stamped shoring plan, and we can prepare the contractor's submittals and sequencing for the Engineer of Record's review.

What to send us

The structural plans and the soils report. With those, we can give you a budget in depth scenarios and a realistic schedule.