Deep Foundations 101: Understanding Your Options for Structural Stability

When most people think about foundations, they picture the concrete slab or basement walls they can see. But for many structures — especially those built on challenging terrain like California's Central Coast — the real foundation work happens deep underground. Deep foundations are the unsung heroes that keep buildings stable when surface soils can't provide adequate support.

Whether you're planning a hillside home in Santa Barbara, dealing with unstable soil conditions, or simply curious about what's holding up the structures around you, understanding your deep foundation options can help you make informed decisions about your construction project.

WHAT ARE DEEP FOUNDATIONS AND WHY DO YOU NEED THEM?

Deep foundations transfer building loads through weak surface soils to more competent load-bearing strata. Think of them as anchors that reach down to more stable ground, oftentimes 50 feet or more below the surface. They're essential when surface soils are too soft, too variable, or simply can't handle the weight of your structure.

Along the Central Coast, deep foundations are particularly important due to expansive clay soils, marine sediments, and areas of fill material that can be unstable or have low bearing capacity. Coastal properties also face unique challenges from groundwater fluctuations, salt water intrusion, potential erosion from storm surge, and corrosive conditions that can affect foundation materials over time.

YOUR DEEP FOUNDATION OPTIONS EXPLAINED

Caissons: The Heavy-Duty Champions

Caissons are large-diameter concrete piers that extend deep into the ground to reach stable soil or rock layers. Picture a massive concrete column buried underground and you've got the basic idea. These foundations are drilled on-site and filled with rebar and concrete, creating incredibly strong foundational support.

Caissons excel in situations requiring high load capacity and are ideal for larger structures or challenging soil conditions. At Kenney Construction, we regularly install large diameter caissons with depths over 60 feet. The main advantages of caissons include their exceptional load-bearing capacity and resistance to lateral forces — important considerations for seismic areas like California.

Helical Piers: The Versatile Performers

Helical piers look like giant screws that are literally twisted into the ground. These steel shafts have helices welded along their length, which drives the drilling action and helps create the bearing capacity.

One of the biggest advantages of helical piers is their versatility. They can be installed in tight spaces, work well in various soil conditions [excluding rocks], and installation creates minimal disturbance to surrounding areas. This makes them particularly popular for residential projects and retrofit applications. Helical piers are also relatively quick to install and can bear loads immediately after installation — no waiting for concrete to cure

Three Decades of Successful Projects

Our team's deep understanding of California's coastal challenges — from shifting soils to salt air exposure — ensures every project is built to withstand the elements.

Micropiles: The Space-Saving Solutions

Despite their name, micropiles pack serious strength into a small diameter — typically ranging from 4 to 12 inches across. These foundations consist of steel reinforcement grouted into a drilled hole, creating a composite pile that combines the strength of steel with the mass of grout.

Micropiles shine in situations with limited access or low headroom, making them perfect for additions to existing structures or projects in tight urban spaces. The installation process is relatively quiet and creates minimal vibration, making micropiles neighborhood-friendly for residential projects.

HOW ENGINEERS CHOOSE THE RIGHT FOUNDATION

Selecting the appropriate deep foundation isn't guesswork — it's a systematic process that considers multiple factors:

Soil Analysis

The foundation selection process begins with comprehensive soil testing. Engineers analyze soil samples from various depths to understand the composition, strength, and behavior of different soil layers. 

Load Requirements

Engineers calculate the total loads the foundation must support, including the weight of the structure, contents, and environmental forces like wind and seismic activity. Different foundation types have varying load capacities and characteristics.

Site Constraints

Practical considerations play a major role in foundation selection. Factors like site access, nearby structures, noise restrictions, and installation space all influence which foundation type is most appropriate.

Economic Considerations

While structural requirements are paramount, cost-effectiveness also influences foundation selection. Engineers balance initial installation costs with long-term performance and maintenance requirements.

THE KENNEY CONSTRUCTION ADVANTAGE

With 30 years of experience installing deep foundations along California's Central Coast, Kenney Construction has encountered virtually every soil condition and foundation challenge the region can present. Our team combines advanced engineering analysis with practical field experience to recommend the most appropriate foundation solution for your specific project.

Our large fleet of drill rigs and expert operators can handle any earth drilling task, from caisson and ground drilling to helical screws, micropiles, tiebacks, and more. Whether you're facing limited access projects, severe slopes, drilling through rock and water, or requiring extreme depths and diameters, our crews and equipment are equipped to deliver results.

With drilling capabilities of large diameters and extreme depths, we regularly install shoring, soldier piles, helical piers, ground screws, tiebacks, and even support bridge foundation projects. No foundation challenge is too complex for our experienced team.

MAKING THE RIGHT CHOICE FOR YOUR PROJECT

Deep foundations represent a significant investment in your structure's long-term stability and performance. The right choice depends on your specific soil conditions, structural requirements, site constraints, and project goals.

Ready to explore options for your project? Contact Kenney Construction today to discuss how our 30 years of Central Coast foundation expertise can ensure your project starts with a solid foundation that lasts.