General Contracting                  License #TRISTC*356R8
About TSI
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Tri-State is a leader in highway and heavy civil construction, site development, and utility construction across the Northwest. 
Tri-State has successfully served municipalities, highway departments, water and sewer districts, and private industry throughout the Pacific Northwest, leaving behind a reputation of quality and value. Tri-State Construction was started by Joe Agostino in 1957; he grew the company from a small utility subcontractor to a diverse prime contractor.  Today, the Agostino family still runs the company and takes pride in the principles that have led to success – responding to clients’ needs, maintaining a strong work ethic, and staying abreast of the cutting edge in construction technologies and methods.


Tri-State maintains a large fleet of construction equipment that complements Tri-State’s labor and professional staff resources.  Tri-State Construction uses craft union labor that is committed to quality, value, and to meeting the needs of clients.  Using these resources Tri-State has the capability and capacity to deliver even the most daunting projects within specified time constraints.  Tri-State has completed over 1000 projects since 1965.  The completed projects range from $10,000 to $91.5 Million in size.  We have extensive knowledge of public works and private development construction.  Many Tri-State employees have worked with the company for a very long time, some over 25 years.  Our long-time employees have helped us to continue forth and provide our clients exceptional expertise and knowledge.

Tri-State Construction is based in Bellevue, Washington.  We are licensed to work in Washington, Oregon, Idaho, California, Montana, Hawaii, Alaska and British Columbia.  We have a secondary office located in Portland, Oregon to allow full service to the local region.  Tri-State keeps our equipment inventory up and running at our 15-acre maintenance facility is based in Kent, Washington.  


Construction Capabilities



Components to TSI Success as a General Contractor


Scheduling & Fast Track Capabilities


Scheduling is a key component to keeping our projects on-time.  Tri-States’ current management team has never failed to meet a required schedule deadline.  Tri-State Construction is well-known for innovative phasing which has led to early completion of numerous projects.  One such project was the WSDOT, SR-202, SR520 to Sahalee Way project which was completed 345 days ahead of schedule.  We used an approach to maximize the utility relocation effort, minimize traffic switches/phasing thus lessen the time to complete and the overall impact to the traveling public.


Tri-State Construction has the ability to complete large volume projects quickly and efficiently.  We have a large fleet of equipment and construction knowledge available to work 24/7 until we get a project complete.  Tri-State has worked on many ambitious high volume projects such as the Port of Seattle Third Runway which required 24/7 work scheduling and import of over 1800 truck loads throughout the project.


 Value Engineering


Tri-State prides itself on the ability to not merely deliver each project, but to deliver exceptional value to each and every owner.  The involvement of experienced and knowledgeable personnel as early in design as possible opens the path to success for TriState’s value engineering services.  Tri-State Construction’s innovation and research into pre-cast materials has provided a large cost savings to many different owners.  Also, we have the ability to understand and acknowledge when we have the opportunity to use cost effective materials in an aesthetically pleasing manner and do so regularly.  We invite our clients to become involved in our program.



Environmental Compliance & Sustainability


Sustainability has become a major factor in today’s construction projects. Tri-State recognizes the importance of sustainable construction – an often overlooked element. Tri-State is dedicated to environmental responsibility which shows through in the completed elements of our projects, which include environmental remediation projects as well as site development work involving bio-swale, detention pond, and natural drainage systems, but also in the methods used to complete all Tri-State projects. From low-emission exhaust systems on key equipment to recycling site demolition rubble, Tri-State remains a northwest leader in environmental sensitivity during construction while successfully executing projects whose final products demonstrate the latest in sustainable construction elements.


Tri-State’s dedication to remaining on the leading edge of advances in construction technologies and methods have made the company a leader in temporary erosion and sediment control methodologies and adherence to water quality standards.  We have established a proven track record in the utilization of cutting-edge chitosan-enhanced sand filtration technology, successfully proving its effectiveness in minimizing turbidity on large-scale projects such as the Port of Seattle’s Seattle-Tacoma International Airport Third Runway Embankment and Downtown Bremerton Pedestrian/BTC Access improvements. Our dedication to our environment is evidenced by the fact that no water quality violations have occurred under our watch despite some of the most restrictive water quality permit conditions in the State.


At Tri-State Construction safety is the number one priority and as such we place the highest value on providing a safe and healthy work place that can be found in the construction industry. As a leader in safety for the construction industry Tri-State Construction has maintained an Experience Modification Rate of .4789 which is the sixth lowest for our industry in the state of Washington. With the combined dedication and efforts of upper managements, foremen, superintendents, and employees, Tri-State Construction has placed themselves well ahead of our competitors in the prevention of workplace injuries. For an effective safety program it takes management commitment, leadership, clear communication, employee involvement, planning and teamwork to achieve excellence.