Mechanical Engineer II (Building Systems Design)

Position Overview Gauthier, Alvarado & Associates , a Northern Virginia-based multidisciplinary Architectural/Engineering firm located in Fairfax, VA, provides Architectural, Structural, Mechanical, Plumbing, and Electrical engineering services across a diverse portfolio of commercial office buildings, educational facilities, public agencies, and interior tenant build-outs. GAA is seeking a mid-level Mechanical Engineer (7–10 years of experience) with a strong background in building systems design to join our growing team. This role is ideal for a hands-on engineer who can independently design mechanical systems with minimal oversight while also serving as a key contributor between senior leadership and junior staff. The successful candidate will play a critical role in developing high-quality construction documents, supporting project delivery, and helping mentor entry-level engineers, while collaborating closely with in-house architects and engineering disciplines. This position is based in our Fairfax, VA office, with a hybrid schedule of 4 days in-office and 1 day remote. Candidates must be current U.S. residents and legally authorized to work in the United States. Visa sponsorship is not available. Responsibilities Lead the design and development of HVAC and mechanical systems for a variety of building types with minimal supervision Prepare detailed construction documents, including drawings, specifications, and system layouts for mechanical and plumbing systems Perform load calculations, system sizing, and equipment selection using industry-standard tools (e.g., Carrier HAP or similar) Collaborate with architects and multidisciplinary engineering teams to ensure coordinated, integrated designs Review projects for interdisciplinary coordination and overall design completeness Provide guidance and mentorship to junior/entry-level engineers Support project managers in meeting deadlines, budgets, and client expectations Ensure designs comply with applicable building codes, standards, and sustainability requirements Participate in construction administration activities, including submittal reviews and site observations Qualifications Bachelor’s degree in Mechanical Engineering from an ABET-accredited university 7–10 years of experience in mechanical design for commercial, educational, and/or government projects EIT certification required; PE license preferred or actively in progress Demonstrated ability to design building mechanical systems independently with limited guidance Strong experience developing construction documents and specifications In-depth knowledge of HVAC systems, including air and hydronic distribution, chillers, boilers, pumps, air handling units, refrigeration systems, and building controls Experience with plumbing system design and coordination Working knowledge of applicable codes, regulations, and industry standards Proficiency in AutoCAD, BIM/Revit, Carrier HAP (or similar load calculation software), and Microsoft Office Strong communication, organization, and writing skills Collaborative mindset with the ability to contribute across experience levels on the team LEED accreditation is a plus A self-starter with strong technical design capabilities and sound engineering judgment Someone who takes ownership of their work and can drive projects forward with minimal direction Ability to work from the Fairfax, VA office 4 days per week with one remote day