Senior/Principal Mechanical Design Engineer

Senior/Principal Mechanical Design Engineer – South Wales (Building Services)
Location: South Wales
Salary: Competitive, depending on experience + package
Job Type: Full-time, permanent
I’m working with a well-established and highly respected Building Services Contractor based in South Wales who are currently looking to strengthen their in-house mechanical design team with the addition of
a Senior or Principal Mechanical Design Engineer .
With a strong pipeline of secured work across a range of sectors – including commercial, education, healthcare, residential, hospitality, and retail – this is an exciting opportunity for someone who wants to step into a role with real responsibility and the backing of an experienced, supportive team.

️ About the Role

This is a lead design role within the business. You’ll be responsible for managing mechanical design from early-stage concept through to technical delivery on site. You’ll act as the main point of contact for clients and design teams, chair project meetings, and ensure that designs are fully coordinated with both internal and external stakeholders.
You’ll also take a key role in supporting and mentoring junior engineers and apprentices in the team – helping to shape the future of the department and pass on your technical knowledge to the next generation.
Projects are varied and often technically challenging, ranging from multimillion-pound new builds to complex refurbishments – so there’s plenty to get stuck into.

Day-to-Day Responsibilities

• Lead mechanical design on projects from concept to completion
• Attend and chair design and coordination meetings
• Work closely with other disciplines and the in-house construction team
• Ensure compliance with relevant building regulations, CIBSE guides, and standards
• Develop detailed designs using relevant software (e.g. Hevacomp, IES, Revit, AutoCAD)
• Oversee and review drawings, schematics, and specifications
• Liaise directly with clients and represent the business in a professional manner
• Mentor junior engineers and support training where needed
• Report project progress to the M&E Design Director

What They\’re Looking For

• Degree or HNC/HND in Building Services Engineering (or similar discipline)
• Solid experience working on mechanical building services design, ideally within a contractor or consultancy
• Comfortable leading the design process and taking ownership of project delivery
• Strong technical knowledge across HVAC, LTHW/CHW systems, and sustainable design
• Good understanding of building regulations, CIBSE codes, and design standards
• Experience with industry-standard software (e.g. Revit, IES, AutoCAD, Hevacomp)
• Good commercial awareness and ability to design within a given budget
• Strong communication skills and confidence engaging with clients and external teams
• Previous experience in a contracting environment is beneficial – but not essential (training can be provided)

What’s on Offer

• A secure, long-term role with a company that values loyalty and invests in its people
• Competitive salary and package (negotiable depending on experience)
• Flexible working arrangements available where needed
• Exposure to a wide variety of technically challenging and rewarding projects
• Real autonomy within a trusted team and clear progression opportunities
• The chance to influence the growth of the design function and contribute to the wider business strategy

If you\’re an experienced mechanical design engineer looking to take that next step – or just want to work on high-quality projects in a company that truly values its staff – I’d love to hear from you.
You can apply directly or get in touch for a confidential chat. #J-18808-Ljbffr