Posted: June 24, 2026Hiring the wrong person is expensive. Most hiring managers know this instinctively. Fewer have sat down and worked out what it actually costs.
In Irish construction and engineering, a bad hire at a professional or management level carries consequences that ripple well beyond the obvious. The recruitment fee is visible. Everything else tends to stay off the balance sheet, even when it is eating into project margin and team performance month after month.
This blog breaks down where those costs actually accumulate, and what firms that get hiring right tend to do differently.
The Numbers Behind a Bad Hire
Various estimates put the cost of a bad hire at anywhere between one and three times the employee’s annual salary. For a white-collar role in Irish construction, that means a poor hiring decision at project manager or senior engineer level could cost your business somewhere between €80,000 and €200,000 when all factors are accounted for.
That figure is not a scare tactic. It is a reasonable estimate when you add up the component parts.
Where the Costs Come From
Recruitment and onboarding
There is the initial recruitment fee if you used an agency, or internal time if you hired directly. Beyond that, there is the cost of onboarding: induction, training, system access, introductions, and the management time involved in bringing someone up to speed. In construction and engineering, that process typically takes longer than in other sectors. Technical roles carry context that cannot be picked up in a week.
Reduced output during the trial period
A new hire operating below the level required is not just producing less. They are often consuming the time of more senior colleagues who are compensating, answering questions, or quietly redoing work. That drag on productivity rarely gets measured, but it is real and it compounds.
The impact on the wider team
In construction, a weak hire at a senior level affects more people than just the individual. A project manager who cannot hold a programme, a quantity surveyor who misses valuations, or a site engineer who needs constant supervision puts pressure on everyone around them. Morale takes a hit when capable colleagues are left to carry someone. In a market where experienced professionals have options, that frustration can accelerate turnover elsewhere in the team.
Delay and project risk
Construction operates on programme. A poor hire in a key role can contribute to delay, rework, or missed milestones. At a time when project pipelines in Ireland are under significant pressure and client expectations are high, those delays have direct commercial consequences.
The exit costs
If the hire does not work out, there are further costs: performance management, HR time, and in some cases legal advice. If the departure happens within the probation period, the process is cleaner. If it does not, it becomes considerably more involved.
Restarting the search
And then you are back at the beginning. A second recruitment process for the same role, often under more pressure and with less patience, and with the best candidates in the market having already seen the original job posted.
Why Bad Hires Happen
Most bad hires in Irish construction and engineering do not happen because hiring managers are careless. They happen because the process was rushed, the brief was unclear, or the shortlist was built around availability rather than fit.
Speed is the single biggest contributor. When a role has been open too long, or a project start date is looming, the instinct is to fill the gap rather than find the right person. An adequate candidate gets hired ahead of the right one. Six months later, the cost of that decision becomes apparent.
Volume-led recruitment processes create similar problems. When a hiring manager is working through a large shortlist of candidates who were submitted quickly and without sufficient qualification, the risk of a poor decision increases. More CVs does not mean better options. It often means more noise and a lower signal-to-noise ratio in the room on interview day.
What Getting It Right Looks Like
Firms that consistently make strong hires in construction tend to share a few characteristics.
They treat the brief seriously. The more clearly a business can articulate not just the technical requirements but the team context, the management style, and what success looks like in the role, the better the shortlist they receive.
They resist the pressure to hire quickly at the expense of hiring well. A short delay to find the right candidate almost always costs less than hiring the wrong one and restarting the process later.
They work with recruiters who understand the sector. A recruiter who knows the difference between a Tier 1 main contractor environment and a specialist subcontractor, and who can have a credible conversation with a senior candidate about programme and commercial structure, will produce a better shortlist than one working from a job description alone.
And they take references seriously, not as a formality at the end of the process, but as a genuine input into the decision.
A Final Word
The cost of a bad hire is not just financial. It is the disruption to a high-performing team, the strain on a project, and the management energy that gets redirected away from delivery and into a problem that should not have existed.
Getting recruitment right the first time is not always possible. But it is far more likely when the process is built around quality rather than speed, and when the people involved in the search are genuinely invested in the outcome.
If you want to understand how Sonas Technical approaches search in a way that reduces this risk, this piece outlines how we work and why we built the business the way we did.