Inspection & Testing Services

Solar Testing Laboratories, Inc. (STL) is a firm certified and authorized to provide inspection and engineering services and can assist you in all aspects of your upcoming project requirements. Using the latest technologies and competent, trained personnel and professional engineering supervision, STL can service your needs more effectively, as well as economically.

Our services assist municipalities, utilities, industrial corporations, and government agencies. With today’s cost of employing service personnel, STL can reduce your costs to pay benefits, insurance, and sick days. By utilizing our services on an as-needed basis, you will find if there is no work, there is no cost to you or your department.

STL performs materials testing and construction inspection of soils, asphalt, concrete, masonry, asphalt, structural steel, fireproofing, firestopping, and roofing. STL provides all administrative and procedural requirements for quality control.  These services include all necessary inspections, tests, and other related activities including reports of test results and contractor activities.  Specific quality control requirements are performed according to American Standards for Testing and Materials (ASTM), American Concrete Institute (ACI), Ohio Department of Transportation (ODOT), National Institute for Certification in Engineering Technologies (NICET), Federal Aviation Administration (FAA), Environmental Protection Agency (EPA), and American Welding Society (AWS) standards as required for each specific construction activity.


Inspection and testing services we offer are as follows:

Soil Compaction

Our technicians provide soil moisture and density measurements to help ensure the proper compaction of fill materials. Moisture and density measurements are taken using a nuclear densometer. Optimum compaction moisture contents and maximum dry densities are measured for various materials using the standard and modified proctor methods.
ASTM D698, D1557, D6938

Concrete and Rebar

Concrete inspection services include field measurements of concrete slump, temperature, and air content. Test specimens are made in the field for later compressive strength testing in the laboratory. Rebar also may be inspected for conformity with project specifications.
ASTM C31, C39, C143, C172, C231, C470, C511, C1064, C1231, E4

Structural Steel

STL’s steel inspection team includes American Welding Society (AWS) certified welding inspectors uniquely lead by an AWS senior certified welding inspector.  STL’s structural steel inspection team possesses not only the highest industry recognized certifications, but it also has combined real world inspection experience in excess of 75 years. The depth of experience of our team creates an environment deeply suited for team collaboration in dealing with unique project elements and challenges. Beyond AWS certifications, each member of STL’s inspection team possesses nondestructive testing (NDT) certifications following the guidelines of American Society of Nondestructive Testing (ASNT), the industry standard for not only the United States but also the world. The paring of certifications through the two largest recognized agencies in structural steel quality control/quality assurance allows STL’s steel inspection team the depth of knowledge in any aspect presented by a client’s project and the ability to ensure that the owner is confident that the project meets all standards and achieves a level of quality for the future.


Our masonry inspection and testing services include compressive strength testing of mortar and grout samples collected in the field, inspection of masonry construction, and compressive strength testing of masonry units. Masonry units which are filled with grout also can be tested for compressive strength.


Asphalt testing services include analysis for proper aggregate gradation and asphalt content, pavement coring, and density measurements using the nuclear densometer method to ensure proper compaction. Other various services that are provided include field inspection of asphalt installation, analysis for mix designs, and measurements of viscosity and other properties.


Firestop is widely recognized as a problematic issue for facilities engineering professionals. It is perhaps the most misapplied and misunderstood segment of life-safety in modern construction. Our qualified firestop inspectors verify the correct installation of firestop to ensure maximum safety for building occupants.

Pile Installation

Our pile inspectors verify the correct installation of a wide variety of deep foundation elements including driven piles, sheet pile walls, drilled shafts or caissons, and augercast piles. Piles installation is inspected for correct location, pile length, depth of penetration, batter angle, and encounter of bedrock.

Bearing Surfaces

Bearing surfaces for spread footings are inspected by our geotechnical engineering staff. Following excavation of a footing, our engineers verify that the strength of the soil at the bearing surface meets or exceeds the bearing pressure specified in project plans. If an adequate bearing strength is not met, our engineers make recommendations for remediation of the problem.

Pavement and Floor Slab Subgrade

Our geotechnical engineering staff performs proof roll inspections on subgrades for pavements and floor slabs to determine the existence of soft areas. When soft or unstable areas of subgrade soil are encountered, recommendations are made for remediating the problem. Our engineers also are available to observe remediation processes to ensure that they are performed adequately.

Laboratory Testing

Filter Media

Our laboratory tests filter media for drinking water and wastewater applications.  We perform sieve analyses to determine uniformity coefficient and effective size. Our laboratory also performs specific gravity, MOH’s hardness, acid and caustic solubility, iodine number determinations, and ball pan hardness tests. We test sand, anthracite, activated carbon, support gravels, and Biolite.

We have been testing filter media for over 20 years and have clients nationwide and in Canada.  We have personnel trained in the proper sampling procedures to ensure getting representative samples in the field. We strive to follow the AWWA specifications in all sampling and testing procedures.