Construction companies have three real options for HR support: hire someone in-house, outsource to a professional employer organization (PEO), or bring in fractional HR leadership on a retainer. A PEO fits best when your priority is buying group benefits and workers compensation you cannot get on your own. An in-house hire makes sense once you have enough daily HR work to fill a full-time salary. Fractional HR fits the contractor in between, with real compliance exposure but not enough recurring paperwork to justify a full-time role. Here is how fractional HR vs. PEO vs. in-house HR compare on cost, control, and construction-specific risk.
What Each Model Actually Delivers
A PEO enters a co-employment relationship with your company. Your crews become jointly employed by you and the PEO, which handles payroll, tax filings, benefits administration, and workers compensation under its own master policy. You keep day-to-day supervision and every hiring and firing decision. Administrative pricing runs either 2 to 12 percent of payroll or roughly $40 to $160 per employee per month, with benefits and workers comp on top.
An in-house HR hire is an employee on your payroll. For a contractor running 30 to 100 people, that is usually an HR generalist, not an HR executive. The Bureau of Labor Statistics puts the median wage for human resources managers at $140,030, and most contractors this size hire well below that. Budget salary plus 25 to 30 percent for taxes and benefits.
Fractional HR is a senior HR advisor working inside your business on a retainer, without co-employment and without a full-time salary. Market rates run roughly $1,500 to $4,000 per month at the generalist level and $4,000 to $7,000 at the director level. You keep your own payroll, workers comp policy, and employer identity.
Fractional HR vs. PEO vs. In-House HR at a Glance
The table below summarizes how fractional HR vs. PEO vs. in-house HR compare on the factors that matter most to a construction company.
| Factor | PEO | Fractional HR | In-House HR |
|---|---|---|---|
| Typical cost | 2 to 12% of payroll, or $40 to $160 per employee per month, plus benefits and workers comp | $1,500 to $4,000 per month at generalist level, $4,000 to $7,000 at director level | $90,000 to $120,000 per year all in |
| Co-employment | Yes | No | No |
| Who holds workers comp | PEO master policy | You do | You do |
| Builds your own EMR | Sometimes, ask before signing | Yes | Yes |
| Payroll processing | Included | Not included | Depends on your systems |
| Certified payroll on prevailing wage jobs | Varies, many PEOs cannot | Advisory only, you file | You file |
| Best fit | Under 25 employees, no public work, cannot access group benefits | 25 to 150 employees with documentation, discipline, and classification gaps | Processes already built and 40 hours a week of HR work |
Run the Cost Comparison Correctly
Most contractors compare these wrong, because they compare the invoice instead of the total.
A PEO quote looks like a service fee, but the real number is what you pay for benefits and workers comp through the PEO versus what you pay today. On a percentage-of-payroll model your HR cost rises every time you add a crew member or run overtime, so the bill peaks in exactly the months your cash is tightest.
An in-house hire looks like a salary, but the real number is salary plus payroll taxes, benefits, workers comp, a payroll system, training, and the cost of the calls a mid-level generalist gets wrong above their pay grade. Most contractors land between $90,000 and $120,000 for one HR person, and that person still calls an attorney for the hard questions.
Fractional HR looks cheap next to both, but it does not include benefits brokerage, payroll processing, or workers comp. You are buying judgment and systems, not administration. If what you need is someone to run payroll every Thursday and chase timesheets, it is the wrong purchase.
Compare all three the same way. Total annual dollars out, and who owns the risk when something goes wrong.
Where PEOs Get Complicated in Construction
PEOs work well in plenty of industries. The fractional HR vs. PEO decision gets more complicated in construction than in most places, and four issues recur.
The first is workers compensation and your experience modification rate. A PEO covers your crews under a master policy that pools risk across many clients, which can genuinely help a contractor carrying a bad claim year. The tradeoff is that some PEOs require you to move onto their rate instead of continuing to build your own mod history. If the general contractors and public owners in your market ask for an EMR certificate at prequalification, and many will not consider a sub above 1.0, that affects what you can bid. Ask before you sign, not three years in.
The second is prevailing wage work. If you bid public or federally funded projects, you have to file certified payroll with correct classifications and fringe accounting, typically on Form WH-347. Plenty of PEOs process payroll competently and have never touched Davis-Bacon. One that cannot produce compliant certified payroll turns a routine weekly filing into a manual reconstruction project when an auditor asks.
The third is what co-employment covers. Under a certified PEO arrangement, the IRS treats the CPEO as solely liable for federal employment taxes on worksite employees. That is real protection, but it does not extend past employment taxes. Discrimination claims, wrongful termination suits, and wage and hour actions can name both parties, and jobsite safety stays yours.
The fourth is the exit. PEO relationships bundle payroll, benefits, and workers comp, so leaving means moving all three at once. Contractors sometimes find the switching cost is what is keeping them, not the value.
How to Choose Based on Where You Sit
If you are under 25 employees, cannot get competitive health benefits on your own, and do not bid public work, a PEO is often the cleanest answer. Buying into a larger benefits pool to compete for talent is a legitimate reason to be there.
If you are running 25 to 150 employees with field crews, turnover, the occasional termination that keeps you up at night, and any prevailing wage or multi-state exposure, fractional HR usually fits better. Your problems at that size are documentation, discipline, and classification. Those need judgment, and they need it before the claim, not after.
If your processes are already built and there is enough transactional work to fill 40 hours a week, hire in-house. The tell is not headcount. It is whether someone in your office is already losing most of a week to HR administration.
Plenty of contractors run a combination. Keeping a PEO or payroll service for administration while using fractional HR for compliance and employee relations is a common and reasonable structure.
What to Do Next
The fractional HR vs. PEO vs. in-house HR decision usually comes down to three numbers. Pull them before your next renewal conversation: total annual spend on your current model including benefits and workers comp, your experience modification rate, and the hours per week your office staff spends on HR tasks.
If you are evaluating a PEO, get two answers in writing. Will we continue to build our own experience modification history, and can you produce compliant certified payroll for prevailing wage projects in the states we work in.
Most contractors we talk to are paying for one model while needing another, and the gap usually shows up during a claim or an audit.
Frequently Asked Questions
Q: Fractional HR vs. PEO: what is the actual difference?
A: A PEO co-employs your workforce and takes over payroll, benefits administration, tax filings, and workers compensation under its master policy. Fractional HR is an advisory relationship with no co-employment, where a senior HR professional works inside your company on a retainer while you keep your own payroll, insurance, and employer identity. A PEO is primarily an administrative and benefits purchase. Fractional HR is primarily a judgment and systems purchase.
Q: Fractional HR vs. PEO: which is better for a 50-person construction company?
A: At 50 employees most contractors have outgrown the main reason to join a PEO, which is access to group benefits they cannot buy alone. What tends to hurt at that size is inconsistent documentation, weak discipline processes, and worker classification exposure, and those call for advisory help rather than more payroll administration. If you bid prevailing wage work or need your own experience modification history for prequalification, fractional HR is usually the better fit.
Q: Is a PEO worth it for a construction company?
A: A PEO is often worth it for contractors under about 25 employees who cannot access competitive group health benefits or affordable workers compensation on their own. It gets harder to justify as you grow, add prevailing wage work, or need your own experience modification history for prequalification. Confirm the PEO can handle certified payroll and Davis-Bacon requirements before signing, since many cannot.
Q: How much does fractional HR cost compared to hiring an HR manager?
A: Fractional HR typically runs $1,500 to $4,000 per month at the generalist level and $4,000 to $7,000 per month at the director level, which works out to roughly $18,000 to $84,000 per year. A full-time in-house HR hire generally costs $90,000 to $120,000 per year once you add payroll taxes, benefits, software, and training to the base salary. The Bureau of Labor Statistics reports a median wage of $140,030 for human resources managers, though most small contractors hire below that level.
Q: Does using a PEO affect my experience modification rate (EMR)?
A: It can. Some PEOs place your crews on their master workers compensation policy and their rate, which means you may not continue building your own mod history during that period. Other PEOs let you preserve your individual experience rating. This matters in construction because many general contractors and public owners require an EMR certificate at prequalification, often with a threshold at or below 1.0. Get the answer in writing before you sign.
Q: When should a construction company hire its own HR person?
A: Hire in-house when there is enough recurring transactional work to fill a full-time schedule, your core HR processes are already built, and you want daily on-site presence. The practical signal is that someone in your office is already spending three or four days a week on HR administration and falling behind. If your need is instead a few complex compliance or employee relations decisions each year, a full-time hire is an expensive way to buy that.