Senior/Principal Mechanical Design Engineer – Building Services Location: Cardiff (Hybrid – 2/3 days per week in the office) Salary: £50,000 - £62,000 An established and growing building services consultancy is seeking a Senior or Principal Mechanical Design Engineer to join its Cardiff office. This is an excellent opportunity for an experienced engineer looking to take ownership of projects, lead client relationships, and play a key role in the delivery of innovative and sustainable building services solutions. The successful candidate will join a collaborative multidisciplinary team working across a diverse portfolio of projects including commercial, healthcare, education, residential, industrial, and public sector developments. The Role As a Senior or Principal Mechanical Design Engineer, you will be responsible for leading mechanical building services designs from concept through to completion, ensuring high-quality technical delivery while supporting the development of junior engineers. Key responsibilities include: Leading the design and delivery of mechanical building services systems. Managing projects through all RIBA design stages. Producing and reviewing detailed calculations, specifications, reports, and technical drawings. Designing HVAC, heating, cooling, ventilation, domestic water, and public health systems. Coordinating with electrical, structural, architectural, and external project teams. Attending client meetings and acting as a technical point of contact. Supporting project planning, resource allocation, and fee management. Mentoring and developing junior engineers and technicians. Contributing to sustainability and low-carbon design strategies. Requirements Degree qualified in Mechanical Engineering, Building Services Engineering, or a related discipline. Proven experience within a building services consultancy environment. Strong knowledge of UK building regulations, CIBSE guidance, and industry standards. Experience delivering projects across multiple sectors. Proficiency with industry software such as Hevacomp, IES, Revit, AutoCAD, or similar. Ability to manage client relationships and lead project teams. Chartered status (CEng) or working towards chartership is desirable. What’s on Offer Flexible hybrid working arrangement (3 days per week in Cardiff). Competitive salary and comprehensive benefits package. Clear progression pathway to Associate level and beyond. Exposure to high-profile and technically challenging projects. Ongoing professional development and chartership support. Collaborative and supportive working culture. If you are interested in this Senior/Principal Mechanical Design Engineer role, please contact Callum at Aztrum via callum.jones@aztrum.com