What Is a Geotechnical Report?

A geotechnical report analyzes the soil and subsurface conditions of a construction site. It is prepared by a licensed geotechnical engineer. The engineer will study factors like the depth of the bedrock, groundwater level, and slope stability.

They do this through field testing and lab work. The goal is to recommend the right foundation type and design. This helps avoid excessive settling, drainage problems, foundation failures, and other issues.

The report provides crucial information for earthworks, grading, drainage, construction considerations, and more. This helps ensure the structural integrity of the buildings on the site.

Often, engineering reports can go a long way toward preventing costly issues down the road. Their insights are quite valuable and can help you make smart design and construction choices.

Types of Geotechnical Reports

Geotechnical engineering companies offer different types of reports. Each type is tailored to the needs of individual projects. The most common types of reports include:

Basic Residential Report

Intended for low-risk home projects, these short reports give general soil conditions at the site. They provide basic foundation recommendations for the home. The engineer will test a few soil samples and give their recommendation for a simple foundation design. The report is usually 5-10 pages long.

Commercial Report

A commercial report is for large, high-risk projects like office towers, shopping malls, and apartments. The engineer does extensive testing across the site, analyzing the soil in depth. Their report includes recommendations for complex foundations and can be over 100 pages.

Preliminary Report

A preliminary report happens early in planning and provides initial findings about the site’s soils. It helps guide early design stages, so more testing may be recommended later to confirm conditions. Not all details are provided in a preliminary report.

Supplementary Report

A supplementary report is issued when new issues come up, or the engineer needs to study something in more detail. They do additional field and lab work and then provide a follow-up report with more data. It supplements the findings of the original report.

Key Factors Affecting Geotechnical Report Costs

There are a few key factors that impact the overall price of writing a report. These considerations can greatly increase the costs compared to a basic soil test. Several key factors determine the overall costs of geotechnical reports including:


The fees charged by engineers and technicians are a big part of the total cost. Engineers charge hourly rates for their work. This includes investigating the site, testing soils, and writing the report.

Lab technicians also charge hourly fees. They test the soil samples and help put the report together. When highly qualified engineers and technicians do the work, it costs more. Their hourly rates are higher than average.


The location of the project has a big impact on the final cost of writing a report. In big cities with higher costs of living, hourly rates are higher. Rural areas often have lower rates.

The number of samples needed also varies by place. Urban sites with complex geology need more testing. This drives up costs.

The engineers look at regional geology maps and records. These help determine how many borings and tests are needed in that area. In places with wide variation in soil types, more samples are taken across the site.

Equipment Usage

Special drill rigs are used to take soil samples from the site. More samples mean the rigs are needed for longer periods, driving up the total cost.

Moreover, other field tests may be required. These include seismic surveys, which check for bedrock depth and sinkhole risks. There are also cone penetrometer tests, which profile the soil layers.

The more equipment that’s involved, the higher the costs. Renting or owning the rigs and tools is expensive too. The engineers have to cover those costs, but advanced equipment can reduce costs in other areas of the study.

Project Scope

The size and use of the planned structure guide the testing needed. A small home needs just a few samples, while a multi-story apartment complex requires more testing. More samples across a bigger area cost more.

High-risk projects like tall buildings require extra care. The engineer does more analysis and takes more samples. Parking garages, bridges, and dams need this level of detail too. The more evaluation needed drives up the cost of a professional report.


Many cities and counties require specific geotechnical tests. This is part of getting a construction permit. The engineering firm must follow strict rules to ensure safety and avoid hefty fines.

Special inspections may be required on-site too. An engineer watches key steps like pouring foundations, which may require having an inspector on site. And while it drives up costs, it ensures quality and safety.

How to Save on the Cost of a Geotechnical Report

Just because engineering reports can be expensive doesn’t mean you can’t save some money on your project. Below are a few tips to get you started.

Compare Quotes From Different Geotechnical Engineering Companies

You can request free estimates from different companies and compare their prices and services. Look for reputable and experienced companies with good reviews and references from previous clients.

Plan and Schedule Your Survey in Advance

You can avoid rush fees and delays by planning your project ahead of time and scheduling your survey well in advance. This will also give you enough time to review the report and make any necessary changes.

Coordinate With Other Contractors

You can coordinate with other contractors who may need to access your site or use similar equipment. For example, if you are installing a septic system, you can share the cost of soil percolation testing with the septic contractor.

Get a Fair Estimate for Your Engineering Report Today!

A geotechnical report is an important document that provides valuable information and guidance for the design and construction. Whatever your engineering report needs, HRK Engineering & Field Services is here. Reach out today to discuss your project scope and get a fair estimate.