Senior mechanical engineer Jobs in St Louis, MO

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 Senior Mechanical Engineer will lead the mechanical design of projects, provide technical expertise, and ensure the successful delivery of engineering solutions for mission-critical facilities, including data centers, advanced manufacturing plants, and other high-availability environments.

This role requires expertise in cooling solutions for air-cooled and liquid-cooled ITE and a track record of delivering complex projects in a dynamic, multidisciplinary setting. You will lead and mentor a team of engineers, collaborate with clients and stakeholders, and design high-performance mechanical infrastructure that meets rigorous uptime and efficiency requirements.

The Specifics of the Role

• Lead the mechanical design for mission-critical facilities, including data centers, advanced manufacturing plants, and other high-availability environments.
• Perform detailed calculations and analyses, ensuring compliance with industry standards, codes, and best practices.
• Manage project timelines, budgets, and resources while coordinating with other disciplines.
• Review and approve mechanical drawings, specifications, and submittals for quality and accuracy.
• Delegate tasks to engineers and other team members, oversee their progress, and provide technical guidance, mentorship and training.
• Develop and present detailed reports and design documentation to clients and project stakeholders.
• Collaborate with project managers to define project scope, schedule, and deliverables, ensuring client expectations are met.
• Manage and track project changes and ensure adherence to project goals, quality standards, and deadlines.
• Support the business development team in pursuing new projects by providing input on RFPs and presentations, attending client interviews, identifying risks and mitigation strategies.
• Oversee construction administration activities, including RFI responses, submittal reviews, and field observations.
• Develop strong client relationships and effectively communicate project requirements, updates, and challenges.
• Stay current with industry trends, emerging technologies, and new software tools to improve design processes and results.

Requirements

• BS degree in Mechanical Engineering from an ABET institution required.
• 8+ years of experience in Mechanical Engineering, with at least 3 years focused on data center projects.
• Professional Engineer (PE) License preferred, with the ability to attain licenses in multiple states; highly experienced unlicensed candidates with strong mission-critical design backgrounds are welcome to apply.
• Strong experience in mechanical systems with working knowledge of plumbing and fire protection systems.
• Proficiency in mechanical design and production software (e.g., AutoCAD, Revit, Trane Trace, Carrier HAP, or similar tools). Proficiency or familiarity with CFD modeling software such as Ansys Fluent, Cadence Reality or similar is a plus.
• Experience with building codes and standards (ICC series, ASHRAE, NFPA etc.) and local/regional codes and regulations.
• Experience working in a design-build or integrated project delivery (IPD) environment is a plus.
• Comprehensive knowledge of construction workflows and their relationship to design.
• Excellent communication, leadership, and problem-solving skills.

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.