Senior Mechanical Engineer - Mission Critical

LJC; St. Louis (MO); On-site; USD 110,000 - 170,000; Full time

Benefits offered by this job

Discretionary annual bonus

Comprehensive benefits package

Job summary

Clayco and its LJC Design & Engineering unit seek a Senior Mechanical Engineer to lead HVAC, plumbing, and fire protection design for mission-critical facilities in a fast-paced, design-build environment. You will oversee calculations, specifications, and drawings for data centers and other high-reliability projects, while mentoring junior engineers and coordinating with project teams.

The role requires a B.S.

Qualifications

• ABET-accredited B.S. in Mechanical Engineering required.
• 10+ years of mechanical engineering experience, with 3+ years on mission-critical projects.
• PE license required to seal engineering documents; multi-state licensure a plus.
• Strong experience in HVAC, plumbing, fire protection, and energy management.
• Proficiency in mechanical design software (AutoCAD, Revit; tools like Trane/Carrier).
• Familiarity with ASHRAE, NFPA, IMC, and local codes; IPD/Design-build experience is a plus.

Responsibilities

• Lead mechanical design for HVAC, plumbing, fire protection, and building systems for mission-critical facilities (data centers, high-reliability environments).
• Perform detailed calculations and analyses ensuring code compliance and quality.
• Manage timelines, budgets, and resources; coordinate with other disciplines.
• Design and specify systems for commercial, industrial, and institutional projects.
• Review and approve drawings, specs, and submittals; mentor junior engineers.
• Develop reports, specifications, and design documentation for clients.
• Collaborate with project managers to define scope, schedule, and deliverables.
• Oversee commissioning, testing, and startup of mechanical systems.
• Track changes and ensure adherence to goals and deadlines.
• Stay current with industry trends and new software tools.

Skills

Leadership

Communication

Problem-solving

Mentorship

Education

ABET-accredited B.S. in Mechanical Engineering

Tools

AutoCAD

Revit

Trane

Carrier

Job description

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 Specifics of the Role

• Lead the mechanical design and engineering of HVAC, plumbing, fire protection, and other building systems for mission-critical facilities, including data centers, advanced manufacturing plants, and other high-reliability environments.
• Perform detailed mechanical system calculations and analyses, ensuring compliance with industry standards, codes, and best practices.
• Manage project timelines, budgets, and resources while coordinating with other engineering disciplines.
• Design and specify mechanical systems, including HVAC, piping, ventilation, and fire suppression systems for commercial, industrial, and institutional projects.
• Review and approve mechanical drawings, specifications, and submittals for quality and accuracy.
• Provide technical guidance and mentorship to junior engineers and other team members.
• Develop and present detailed reports, technical specifications, and design documentation for clients and project stakeholders.
• Collaborate with project managers to define project scope, schedule, and deliverables, ensuring client expectations are met.
• Oversee commissioning, testing, and start-up of mechanical systems to ensure proper operation.
• Manage and track project changes and ensure adherence to project goals, quality standards, and deadlines.
• Stay current with industry trends, emerging technologies, and new software tools to improve design processes and results.

Requirements

• Bachelor's degree in Mechanical Engineering (or related field) from an ABET institution required.
• 10+ years of experience in Mechanical Engineering, with at least 3 years focused on mission-critical projects (data centers, high-tech manufacturing, etc.).
• PE License is required to seal engineering documents, with the ability to attain licenses in multiple states.
• Strong experience in HVAC, plumbing, fire protection systems, and building energy management.
• Proficiency in mechanical design software (e.g., AutoCAD, Revit, Trane, Carrier, or similar tools).
• Experience with building codes and standards (ASHRAE, NFPA, IMC, etc.) and local/regional codes and regulations.
• Experience working in a design-build or integrated project delivery (IPD) environment is a plus.
• 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).
• 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.