Quality Construction Services

Materials Laboratory

OSG maintains a fully accredited construction materials testing laboratory in Redmond, Washington. Our laboratory operates within an ISO 9001 compliant framework.  We maintain local and national accreditation from the Washington Association of Building Officials (WABO), and the American Association for Laboratory Accreditation (www.A2LA.org, Certificate #3381.01).   In addition, our materials laboratory is approved by WSDOT and Sound Transit to support their ongoing roadway and light rail projects.

We participate in proficiency testing programs administered by:

  • American Association of State Highways and Transportation Officials (AASHTO)
  • Cement and Concrete Reference Laboratory (CCRL)
  • AASHTO Materials Reference Laboratory (AMRL)
  • American Society for Test and Materials (ASTM)


These organizations provide material samples with known characteristics or values and are periodically evaluated for results/performance as compared to other laboratories. Their statistical analysis indicates our results are well within the acceptable range of standard deviation.  These accreditations establish traceability to the Nation Bureau of Standards, and confirm our compliance to ISO 17025 & ISO 9001.   Maintenance of these accreditations requires strict adherence to our quality program outlined in our Laboratory Quality Manual with periodic audits from external organizations.