Principal MEP Mechanical Engineer

Principal MEP Mechanical Engineer

Outside IR35

Hybrid

Role Purpose

The Principal MEP Mechanical Engineer will lead the mechanical engineering delivery of residential and commercial construction projects from pre-construction through commissioning and handover. The role acts as the senior mechanical technical authority, ensuring systems are compliant, coordinated, cost-effective, and buildable while supporting programme, quality, and safety objectives.

Key Responsibilities

Technical & Delivery Leadership

Lead mechanical engineering delivery across multiple residential and commercial projects.
Take ownership of mechanical design development and construction-stage design responsibility on D&B projects.
Review, challenge, and manage consultant designs to ensure buildability, value, and programme certainty.
Ensure compliance with UK legislation and standards, including:
Building Regulations (Part L, Part F, Part O, Part G)
CIBSE Guides and Technical Memoranda
BS EN standards and relevant British Standards
BSRIA commissioning guides
Heat Network (Metering and Billing) Regulations where applicable
Provide technical leadership across HVAC, domestic water services, drainage, above-ground soil and waste, and specialist mechanical systems.

Pre-Construction & Design Management

Provide mechanical input into bids, tenders, and pre-construction activities.
Review Employer's Requirements, specifications, and performance criteria.
Lead value engineering, alternative solutions, and risk mitigation strategies.
Coordinate mechanical design with electrical, public health, structural, architectural, and fire engineering teams.
Manage RFIs, design changes, and technical submissions.

Site Support & Construction Phase

Provide senior mechanical engineering support to site and project teams.
Attend site meetings, coordination workshops, and technical reviews.
Support installation quality, inspections, pressure testing, flushing, and commissioning.
Resolve on-site mechanical issues, non-conformances, and installation constraints.
Oversee commissioning strategies, witnessing, O&M manuals, and handover documentation.

Commercial & Programme Management

Work closely with commercial and procurement teams to manage cost, variations, and supply chain performance.
Support procurement strategies for plant, equipment, and specialist subcontractors.
Ensure mechanical works align with construction sequencing and programme milestones.

Leadership & Team Development

Act as senior mechanical authority and mentor for engineers, design managers, and site teams.
Support the development and technical competence of junior mechanical engineers.
Promote best practice in safe design, quality assurance, and constructability.

Health, Safety & Compliance

Promote safe-by-design principles and contractor H&S standards.
Fulfil Designer duties under CDM Regulations 2015 where required.
Ensure compliance with company QA systems, ISO standards, and statutory requirements.

Skills & Competencies

Technical Skills

Strong contractor-side experience delivering mechanical services on residential and commercial developments.
In-depth knowledge of HVAC systems including:
Air-source and ground-source heat pumps
VRF/VRV systems
Gas-fired and electric heating systems
Mechanical ventilation (MVHR, smoke control interface)
Strong understanding of domestic water services, boosted systems, drainage, and water efficiency.

Experience with BIM Level 2 coordination using Revit and Navisworks.

Professional Skills

Strong leadership and decision-making capability in live construction environments.
Clear and effective communication with site teams, consultants, subcontractors, and clients.
Commercially aware, pragmatic, and solutions-focused.
Ability to manage multiple projects concurrently.

Qualifications & Experience

Degree or HNC/HND in Mechanical Engineering or Building Services Engineering (or equivalent).
Chartered Engineer (CEng) or Incorporated Engineer (IEng) status desirable; working towards acceptable.
Typically 10+ years' experience in UK building services engineering, with significant contractor-side delivery experience.
Proven experience delivering residential and commercial projects through construction and handover.

Desirable Experience

High-rise residential schemes (including ventilation, overheating, and fire strategy interfaces).
Low-carbon and net-zero technologies, including heat networks and renewable systems.
Tier 1 or Tier 2 main contractor environment.
MMC, prefabrication, and off-site plant solutions.

ersg are an equal opportunities employer; we are committed to promoting equality of opportunity for all job applicants. We do not discriminate against applicants on the basis of age, sex, race, disability, pregnancy, marital status, sexual orientation, gender reassignment or religious background; all decisions are based on merit