Assistant Engineer Jobs in Missouri (NOW HIRING)

About Us

Clayco is a full-service, turnkey real estate development, master planning, architecture, engineering, and construction firm that safely delivers clients across North America the highest quality solutions on time, on budget, and above and beyond expectations. With $8.1 billion in revenue for 2025, Clayco specializes in the "art and science of building," providing fast track, efficient solutions for mission critical, industrial, life sciences, power & energy, aviation, commercial, institutional, residential and sports & entertainment related building projects.

About LJC

LJC Design & Engineering is a full-service architecture, engineering, and design firm committed to enhancing the quality of the human experience through integrated design. We are a team of high-energy professionals who share a passion for design, a collaborative approach, and a casual culture. We solve challenges by leveraging the collective expertise and ingenuity of the best and brightest minds across development, design, and construction.

The Role We Want You For

The Entry-Level Mechanical Engineer will support the mechanical design of mission-critical facilities, including data centers, advanced manufacturing plants, and other high-availability environments. This is an excellent opportunity for an early-career engineer to gain hands-on experience with complex mechanical systems, high-performance infrastructure, and integrated design project delivery.

In this role, you will work closely with engineers, project managers, and other disciplines to support mechanical design efforts from concept through construction. You will assist with calculations, system layouts, equipment selections, drawing production, and coordination while developing a strong foundation in mission-critical design.

The Specifics of the Role

• Assist engineers in producing mechanical design deliverables including drawings and specifications.
• Perform basic calculations (load calcs, system sizing, pipe pressure drop, duct pressure drop etc.) and assist with miscellaneous design tasks under the supervision of senior staff.
• Coordinate with other disciplines including civil, structural, architectural, electrical, plumbing, and controls to support integrated design.
• Participate in construction administration tasks, including RFI responses, submittal reviews, and field observations.
• Learn and apply ICC, ASHRAE, NFPA and other relevant code series and standards.
• Develop technical skills through mentorship, project exposure, and continuing education.

Requirements

• BS degree in Mechanical Engineering from an ABET institution required.
• 0-3 years of experience in Mechanical Engineering; internship or co-op experience in mission-critical, data center, or industrial projects is a plus.
• EIT certification or ability to obtain within first year of employment required.
• Familiarity with AutoCAD and Revit; exposure to load calculations software such as Trane Trace, Carrier HAP or similar; exposure to CFD modeling software such as Ansys Fluent, Cadence Reality or similar is a plus.
• Ability to break down complex challenges and communicate clear, actionable solutions.
• Highly organized with ability to manage and pivot between concurrent projects.
• Strong communication, collaboration, and problem-solving skills, with a willingness to learn in a fast-paced environment.

Some Things You Should Know

• No other builder can offer the collaborative design-build approach that Clayco does.
• We work on creative, complex, award-winning, high-profile jobs.
• The pace is fast!

Why Clayco and LJC?

• 2025 Best Places to Work – St. Louis Business Journal, Los Angeles Business Journal, and Phoenix Business Journal.
• 2025 ENR Top 400 – Top Data Center Contractor (Top 3).
• 2025 ENR Top 100 Design-Build Firms – Design-Build Contractor (Top 5).
• 2025 ENR Top 100 Green Contractors – Green Contractor (Top 3).

Benefits

• Discretionary Annual Bonus: Subject to company and individual performance.
• Comprehensive Benefits Package Including: Medical, dental and vision plans, 401k, generous PTO and paid company holidays, employee assistance program, flexible spending accounts, life insurance, disability coverage, learning & development programs and more!

Compensation

• The salary range for this position considers a wide range of factors in making compensation decisions including but not limited to: Education, qualifications, skills, training, experience, certifications, internal equity, and location. Compensation decisions are dependent on the facts and circumstances of each case.