Senior Project Engineer – Mechanical U.K (Data Centre Retrofit)

About the job:

As a Senior Project Engineer – Mechanical, you will play a key role within Ethos’ Data Centre team, with a focus on retrofit projects across mission-critical data centre environments.

You will lead the design, specification and delivery of mechanical systems, ensuring projects are delivered safely, efficiently and to the highest technical standards. Working within live environments, you will help maintain continuity of operations while delivering high-quality engineering solutions.

This role will also involve managing project delivery, mentoring junior engineers and acting as a key technical point of contact for clients and contractors across major European data centre markets.

Your day-to-day activities:

• Lead the design and delivery of mechanical building services upgrades within live data centre environments, including M&E upgrades, capacity increases, technology refreshes, phased refurbishments, and lifecycle replacements.

• Develop and manage retrofit-specific design strategies, including tie-ins to live systems, redundancy planning, outage and staging strategies, and resilience design.

• Conduct or oversee technical due diligence of existing data centre facilities, including capacity unlock assessments (power, cooling, and white space).

• Prepare and review detailed design drawings, schematics, schedules, technical reports, and tender documentation.

• Manage project scope, budget, programme, and contracts — identifying and mitigating scope creep, risks, and live-environment constraints.

• Liaise directly with clients (hyperscale, colocation, and enterprise operators), contractors, and vendors to ensure project goals are achieved with zero operational disruption.

• Drive quality assurance and governance across all assigned projects, adhering to WAP/PTW protocols in live environments.

• Mentor and support the development of junior engineers and graduate staff within the retrofit workstream.

• Support business development by contributing to proposals, client presentations, and technical strategies for retrofit opportunities across EMEA.

• Champion innovation in live-environment engineering and contribute to the continuous improvement of Ethos’ retrofit delivery model.

• Lead phasing strategy for live cooling and HVAC upgrades, ensuring continuity of critical mechanical infrastructure throughout delivery.

About you:

Technical Skills

• Strong expertise in mechanical systems design for live data centre environments, including chilled water plant, CRAC/CRAH upgrades, air handling units, in-row cooling, and fire suppression systems.

• Experience delivering M&E upgrades within operational facilities — including tie-ins to live plant, outage management, and resilience planning.

• Proficient in AutoCAD, Revit MEP, Bluebeam, and Microsoft Office; working knowledge of IES, HAP, or similar mechanical analysis tools is advantageous.

• Strong knowledge of CIBSE, ASHRAE, BS, IS, and EN standards applied in retrofit and live-environment contexts.

• Understanding of PUE optimisation and cooling efficiency improvements to meet EU Energy Efficiency Directive targets and client ESG requirements.

• Familiarity with commissioning and integration of mechanical systems within live, mission-critical facilities.

Experience & Qualifications

• Bachelor’s or Master’s degree in Mechanical Engineering or a related discipline.

• Minimum 8 years’ experience in building services engineering, with at least 3 years focused on data centre or mission-critical projects.

• Demonstrable experience working in live, operational data centre environments — including brownfield upgrades, M&E replacements, or phased refurbishments.

• Chartered Engineer status (or actively working towards Chartership) with Engineers Ireland or equivalent.

• Proven track record managing multi-million-euro MEP projects from concept to completion.

• Strong understanding of Irish and EU building regulations; knowledge of LEED/BREEAM and the EU Energy Efficiency Directive is an advantage.

Soft Skills

• Excellent communication and presentation skills, with confidence in client-facing settings.

• Strong organisational and problem-solving abilities, capable of managing multiple concurrent retrofit projects.

• Collaborative approach to working across multidisciplinary teams including mechanical, electrical, sustainability, and BIM disciplines.

• Proactive, detail-oriented mindset with a sharp focus on risk management and technical quality in live environments.

• Calm under pressure — able to make sound engineering decisions within constrained, operational environments.

Why Join Us?

At Ethos, we’re dedicated to fostering an environment that encourages both technical excellence and personal wellbeing.

We offer:

• Flexible Fridays and a 9-day fortnight working schedule — enjoy every second Friday off to maintain work–life balance.

• A culture that values flexibility, learning, and teamwork, with clear progression pathways and support toward professional accreditation.

• Opportunities to work alongside some of the most experienced engineers in the industry, within a forward-thinking, technology-driven consultancy.

Benefits:

• Flexible working times

• 25 Days holidays

• Pension Scheme

• Working travel out-of-pocket expenses

• Regular training/mentoring / further college support

• Support for Chartership

• Subsidised Health Insurance Allowance

• A Professional Subscription Fee paid by the company

• Paid Statutory Leaves

• Referral scheme

• Heavily subsidised social committee (5 a side, golf society, climbing club and regular social events)

At Ethos, we offer Flexible Fridays every second Friday as a perk! Apply today and take the first step towards a healthier work-life balance!

Company Description:

Ethos is a team of collaborative and creative consultant engineers & professionals, leading data centre and energy infrastructure projects globally.

Our Charter:

• We believe in strong human relationships

• We believe clear leadership lights the path

• We believe sustainability is non-negotiable

• We believe a can-do mindset can move mountains

• We believe in a relentless focus on delivery

Our Tagline:

Performance Made Possible