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Soil Borings – Florida

Soil borings are the foundation of every geotechnical investigation in Florida. Foundation Masters, LLC performs Standard Penetration Test (SPT) borings, Continuous Cone Penetration Tests (CPT), hand augers, and rock coring to evaluate soil profiles, groundwater conditions, and subsurface risks across coastal and inland areas.

SPT Soil Boring Rig in Florida
SPT drilling operations

We perform soil borings for residential, commercial, industrial, and municipal projects throughout Tampa Bay, Sarasota, Orlando, Miami, and all Florida counties. Our borings follow ASTM standards and provide precise data for engineering foundations, ground improvement, settlement analysis, and sinkhole/karst evaluation.

What Soil Borings Reveal

SPT soil borings provide critical subsurface information:

  • Soil types and stratification (SM, SP, SC, CL, ML, organics)
  • Strength and density using N-values
  • Depth to limestone or competent bearing layers
  • Seasonal high-water table (SHWT)
  • Presence of fill soils, organics, or loose zones
  • Void potential in karst regions

Accurate boring data ensures proper foundation design and prevents settlement, heave, structural cracking, and water intrusion.

The SPT Boring Process (ASTM D1586)

Typical Florida boring sequence:

  1. Advance hollow-stem augers to the first test depth (commonly 5 ft).
  2. Insert split-spoon sampler and drive with a 140-lb hammer falling 30 in.
  3. Record blows for three 6-inch intervals:
    N-value = blows for last 12 inches (standard penetration resistance).
  4. Recover sample, classify soil (Unified Soil Classification System).
  5. Advance augers to next test depth (usually every 5 ft).
  6. Log groundwater level during and after drilling.
  7. Terminate at design depth, limestone, or auger refusal.

Typical Florida depths:

  • Coastal zones: 10–25 ft
  • Inland suburbs: 15–40 ft
  • Karst areas (Pasco / Hernando): 40–80 ft or until rock confirmation
  • High-rise or heavy loads: 50–120 ft+

Refusal criteria:

  • 50 blows for 6 in. penetration
  • Or 100 blows for 12 in. penetration
  • Or inability to advance augers

Common Florida Soil Profiles

Florida’s geology varies dramatically by region. Boring logs commonly encounter:

  • Clean sands (SP) – common near coasts; may cause settlement if loose.
  • Silty/clayey sands (SM/SC) – moderate strength; varies by density.
  • Clay layers (CL/CH) – can shrink/swell, causing movement.
  • Organic soils (OL/OH/peat) – highly compressible, unsuitable for foundations.
  • Fill material – variable; requires verification for bearing capacity.
  • Limestone – depth varies from 1 ft to 80+ ft depending on county.
  • Karst features – voids, weathered zones, raveling soils.

We maintain a large internal database of Florida boring logs to help anticipate soil behavior before drilling begins.

What You Receive in a Soil Boring Report

A complete boring log includes:

  • Boring location & ground elevation
  • Soil stratigraphy with depth
  • N-values at test intervals
  • Soil classification & sample descriptions
  • Groundwater depth (during & after drilling)
  • Limestone/rock elevations
  • Photographs (if required)

These results are used for foundation design, settlement analysis, ground improvement, and sinkhole/void assessment.

When Soil Borings Are Required

  • New residential & commercial construction
  • Additions, remodeling & structural modifications
  • Retaining walls, seawalls & deep foundations
  • Pools & waterfront structures
  • Sinkhole or void investigation
  • Roadways, pavements & drainage improvements

Building officials frequently require geotechnical borings before issuing structural permits.

Soil Boring FAQs

How many soil borings does my project need?
Small homes often require 1–3 borings. Commercial buildings may need 4–20 depending on footprint, loads, and subsurface variability.
How deep do borings go?
Most Florida borings extend 15–40 ft. Heavy structures may require 50–120 ft to reach competent bearing material.
Do all Florida sites have limestone?
No. Some coastal areas have no shallow limestone. Inland counties may encounter rock at 5–20 ft, while karst zones may reach 40–80 ft+

Schedule Soil Borings

To request geotechnical borings anywhere in Florida, contact:

Foundation Masters, LLC – Engineering Division
Phone: 813-614-7178
Email: jeff@foundationmasters.com


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