Meet the Team


Jim Coslett P.E.

Jim Coslett P.E.—Principal Engineer

A graduate of the University of Southern California, Jim has over 25 years of civil engineering experience in the consulting industry. He worked in the public sector for both state and county agencies in Northern California. In the private sector, he has managed a variety of projects in California and Idaho, including:

        Large, master-planned subdivisions      
        Complicated floodplain developments      
        Foothills developments      
        Municipal engineering projects

By working in both the public and the private sector, Jim learned how to engineer large complex projects, manage staff, and run a business. These experiences also gave Jim the foundation for Rock Solid Civil’s philosophy and vision.




Ken Nguyen

Ken Nguyen—Staff Engineer

Ken earned his Bachelor of Science degree in Civil Engineering from Cal Poly San Luis Obispo and has over 18 years of civil and environmental engineering experience. Since 1994, he has worked on a variety of engineering projects in different geographical locations, including the San Francisco Bay Area; Portland, Oregon; and Boise, Idaho.

Ken provides infrastructure planning and design services for all phases of project development and delivery. He actively works with clients, developing detailed plans and specifications for all aspects of civil/environmental engineering projects. He conducts cross-disciplinary coordination, engineering design, cost estimations, agency permitting/approvals, and construction administration.





Derritt Kerner

Derritt Kerner, P.E.

A graduate of Boise State University and a veteran of Operation Iraqi Freedom, Derritt joined Rock Solid Civil in 2014. At Rock Solid, we appreciate Derritt not only for his service to our country but also for his experience working for the Ada County Highway District.

Derritt has worked on a wide variety of projects including both residential and commercial. He works directly with project owners, architects, building officials, and other engineers on a daily basis.








Randy Carpenter

Randy Carpenter—Senior Civil Engineering Designer

Randy is a graduate of ITT Technical Institute with an Associates of Applied Science degree. He has experience in civil construction management and specializes in providing comprehensive site layout and design plans for commercial and single-family construction projects. He brings to the firm over 20 years of civil engineering design and CAD experience.









Amy King

Amy King—Office Manager

Amy is a graduate of ITT Technical Institute with an Associates of Applied Science degree. Amy oversees nearly everything that happens in our office—record keeping, HR services, you name it.

Amy’s background includes solid experience with architectural, construction and engineering firms. She has spent many years helping small businesses develop into fully functional and successful organizations. She is a big reason why Rock Solid Civil delivers quality service to its clients.








Seijoon Song

Seijoon Song, E.I.T.

Seijoon Song is a graduate from Boise State University and earned his Bachelors of Science degree in Civil Engineering. Seijoon has experience working for the ADA County Highway District (ACHD), where he worked closely with superintendents and lead-workers in the maintenance department serving partially as a Project Manager/Inspector/Estimator.

With his experience at ACHD, he is able to apply his construction knowledge and background to the design aspects of civil engineering. Seijoon is fairly new to Rock Solid but already has gained experience working on projects in both residential and commercial settings and will be a big asset to the company.








John Fitzgerald-CAD Designer

John graduated from ITT Technical Institute in 1991 with an Associates of Applied Science degree in Computer-Aided Drafting. He has been working in the civil engineering field since 1990 with occasional sabbaticals to work on a computer science degree at Boise State University. John has worked on a myriad of engineering projects including subdivisions, highways, bridges, municipal utilities, single-family, multi-family and site topography among others as well as developing custom tools for Autocad. He specializes in foothills grading and drainage design, drafting topographies, subdivision development plans and tool development.