You won the bid. The project is on the books. Now you need subs — and not just any subs. You need subs who can actually perform, carry proper insurance, show up with the right certs, and not blow up your schedule or your liability exposure.
That's what subcontractor prequalification is about. It's the process of evaluating a subcontractor's qualifications, financial health, safety record, and documentation before they ever set foot on your jobsite.
Most GCs have some version of this process. The question is whether it's consistent, documented, and actually catching the risks it's supposed to catch.
Why Prequalification Matters
Every subcontractor you bring onto a project introduces risk. Their workers' comp claims affect your experience modification rate. Their safety violations can trigger an OSHA inspection of your entire site. Their insurance gaps can leave you holding the liability.
Prequalification is how you manage that risk before it becomes a problem.
The cost of skipping it:
- A sub with lapsed workers' comp gets injured on your site — you're liable for their medical costs
- A sub without proper GL coverage causes property damage — your insurance covers it, your premiums spike
- A sub with a history of safety violations draws an OSHA inspection — every sub on your site gets scrutinized
- A sub who can't manage cash flow walks off the job mid-project — you scramble for a replacement at premium rates
What to Evaluate
A solid prequalification process evaluates subcontractors across five areas:
1. Insurance and Bonding
This is the non-negotiable baseline. Before anything else, verify:
- General liability insurance with limits that meet your contract minimums (typically $1M per occurrence, $2M aggregate)
- Workers' compensation insurance active in the state where work will be performed
- Auto liability if the sub will operate vehicles on your site
- Umbrella/excess coverage if your contract requires it
- Your company listed as additional insured on their GL policy
- Bonding capacity for the scope of work (if applicable)
Don't just check the certificate of insurance — verify it directly with the carrier. Fraudulent COIs are more common than most GCs realize.
2. Safety Record
Request the sub's:
- Experience Modification Rate (EMR) — an EMR above 1.0 means their injury rate exceeds the industry average
- OSHA 300 Log summary (Form 300A) for the past three years
- Total Recordable Incident Rate (TRIR) and Days Away, Restricted, or Transferred (DART) rate
- Any OSHA citations in the past five years
- Safety program documentation — do they have a written safety program? Who manages it?
An EMR of 1.2 or higher is a red flag. Some GCs set a hard cutoff at 1.0. Others evaluate it in context — a small sub with one bad year can spike their EMR temporarily.
3. Financial Health
A sub who can't meet payroll is a sub who won't finish your project. Evaluate:
- Bank references or financial statements (for larger scopes)
- Trade references from recent projects
- Payment history — do they pay their suppliers and lower-tier subs on time?
- Current backlog — are they overextended?
- Bonding capacity as a proxy for financial stability
You don't need a forensic audit. But for scopes above $500K, requesting basic financial documentation is standard practice.
4. Licenses and Certifications
Verify that the sub holds:
- Active contractor's license in the relevant jurisdiction
- Trade-specific certifications (electrical, plumbing, HVAC, etc.)
- OSHA 10 or OSHA 30 certifications for their field supervisors
- Specialty certifications required by the project (confined space, fall protection, etc.)
- Business license and W-9 for tax compliance
Every state has different licensing requirements. Don't assume — verify against the state licensing board's database.
5. Experience and References
- Similar project experience — have they completed work of this type and scale?
- References from other GCs — not just the ones they hand-pick
- Current project load — do they have capacity for your timeline?
- Key personnel — who will be the foreman on your site? What's their experience?
Building Your Process
The difference between GCs who get burned by bad subs and those who don't usually comes down to consistency. A prequalification process only works if you apply it to every sub, every time.
Start with a standard form. Create a prequalification questionnaire that covers all five areas above. Send it to every sub before they bid.
Set minimum requirements. Define your baseline: minimum insurance limits, maximum EMR, required certifications. Make these non-negotiable.
Verify independently. Don't take the sub's word for it. Call insurance carriers. Check licensing databases. Pull OSHA records from the public database.
Document everything. Keep a file for every sub with their prequalification documents, verification records, and any issues flagged. This protects you in disputes and audits.
Track expirations. Insurance policies expire. Licenses expire. Certifications expire. If a sub was qualified six months ago, their documents may be invalid today. Set up a system to track expiration dates and request renewals.
Common Mistakes
Applying different standards to different subs. Your prequalification requirements should be the same whether it's your go-to electrical sub or a new concrete crew. Inconsistency creates liability gaps.
Only prequalifying at bid time. Prequalification isn't a one-time event. Documents expire, financial situations change, safety records evolve. Re-evaluate annually at minimum.
Not verifying insurance independently. A certificate of insurance is a snapshot, not a guarantee. Call the carrier. Five minutes on the phone can save you from a fraudulent COI.
Skipping prequalification for small scopes. A $50K sub can cause a $500K problem. The scope of work doesn't determine the scope of risk.
Frequently Asked Questions
How far in advance should I prequalify subs? Start the prequalification process as soon as you begin soliciting bids. Allow at least two weeks for subs to compile and submit their documents.
What if a sub doesn't meet all my requirements? That depends on which requirement they miss. A missing OSHA 30 cert might be obtainable before the project starts. An EMR of 1.5 is a fundamental risk issue. Use judgment, but document your decision either way.
Should I prequalify subs I've worked with before? Yes. Verify that their insurance is current, their safety record hasn't changed, and their financial health is stable. Trust but verify — every time.
How do I handle subs who push back on prequalification requirements? Professional subcontractors expect prequalification. If a sub resists providing basic documentation, that tells you something about how they'll handle compliance on your project.