In construction, engineering resourcing is often underestimated, until problems emerge. Site engineers play a critical role in ensuring quality, safety, and programme compliance. But how many engineers does a project actually need?
While each job is different, there are practical ratios and patterns that experienced teams rely on. Based on common mid-size and large project structures, here’s how to approach engineering resourcing more realistically.
Core ratios and practical guidelines
– One Site Engineer can typically set out and support 15–20 operatives on site.
– Once the workforce reaches around 50 operatives, the minimum recommended engineering team is:
• 2 Setting Out Engineers
• 1 Dedicated QA Engineer
• 1 Senior or Project Engineer
This structure ensures safe and efficient execution while maintaining programme and compliance standards.
Key engineering roles and responsibilities
- Setting Out Engineers: Responsible for drainage, RC works, steel installation, and external works. These engineers often move between packages, starting with drainage and progressing into frame or finishing.• QA Engineer: Becomes essential as the workforce and activity increases. Manages inspection and test plans, pre-pour checks, and handovers. Also oversees record-keeping for compliance.• Senior/Project Engineer: Manages RFIs, technical queries, CDP packages, and interfaces with the design team, architects, and subcontractors. Plays a crucial role in maintaining buildability and coordinating information flow.
Phased work requires flexible engineering support
While estimates often suggest one engineer per section (e.g., drainage, RC, externals), real-world delivery involves engineers rotating between these areas as the project progresses. For example:
– An engineer may complete drainage setting out early in the programme and transition to RC slab setting out.
– The QA role becomes increasingly vital during high-volume concrete pours and structural finishes.
A flexible approach to engineering allocation helps maintain momentum and prevents duplication or underperformance.
Example: Project with 50 site operatives
Here’s a typical engineering allocation for a busy site with around 50 operatives:
• 2 Setting Out Engineers
• 1 QA Engineer
• 1 Senior or Project Engineer
Total: 4 Engineers
This structure ensures site control, quality assurance, and design coordination are all adequately covered.
Final Thoughts
Under-resourcing engineering roles can lead to costly mistakes, rework, and delays. By applying simple ratios and scaling your team as the site grows, you can maintain technical control without overloading your engineers. This flexible, phased approach reflects how modern construction sites operate and ensures consistent delivery through every stage of the project.