Most small contractors don't have a compliance department. They have a phone full of PDFs, a folder of W-9s from three years ago, and a vague sense that someone's insurance is probably expired. Usually nothing happens. When something does, a missing document can turn a sub's problem into yours.
Here's a straightforward checklist of what to collect from every subcontractor before they start work, why each item matters, and how to keep it all current. Requirements vary by state, by client, and by your own insurer, so treat this as a starting point and confirm the specifics with your agent or attorney.
The checklist
| Document | When to collect | Expires? |
|---|---|---|
| Signed subcontract agreement | Before work starts | Per contract |
| W-9 | Before the first payment | No, but update if their business details change |
| Certificate of insurance (general liability) | Before work starts | Yes, usually yearly |
| Workers' comp certificate, or proof of exemption | Before work starts | Yes, usually yearly |
| Trade license (electrical, plumbing, HVAC, etc.) | Before work starts, where required | Yes, varies by state |
| Auto liability (if they drive for the job) | Before work starts, if your contract requires it | Yes |
| Safety training (e.g., OSHA 10 / 30) | If your state, client, or project requires it | Varies |
| Lien waivers | With each payment, where used in your state | Per payment |
Why each one matters
Signed subcontract agreement
The agreement sets the scope, price, payment terms, schedule, and the insurance the sub has to carry. Without it, the insurance minimums you check against don't exist on paper. Get it signed before anyone's on site.
W-9
You'll need the sub's legal name and taxpayer ID to file a 1099-NEC for what you pay them. Collect the W-9 before the first payment; chasing it in January is much harder. Check that the name matches the business on the subcontract and the insurance certificate.
Certificate of insurance (COI)
Proof the sub carries general liability insurance, so damage or injuries from their work are covered by their policy rather than yours. Check the limits, the expiration date, and, if your contract requires it, that you're listed as an additional insured. Our guide on how to read a certificate of insurance walks through every field.
Workers' comp
If a sub's employee is hurt on your job and the sub has no workers' comp, many states can treat you as responsible, and your own insurer may charge premium for that sub's payroll at audit. Some sole proprietors without employees are allowed to go without coverage; in that case, collect whatever exemption certificate or form your state uses.
Trade license
Electrical, plumbing, HVAC, and other licensed work generally has to be done by someone holding the right state or local license. Using an unlicensed sub can create problems with permits, inspections, and your own license. Most states let you look up a license number online in a minute.
Lien waivers
In many states, an unpaid sub or supplier can file a lien on the property even if you paid the sub. Collecting a lien waiver with each payment is common protection, and the rules for what form to use vary widely by state.
The part everyone forgets: keeping it current
Collecting documents once is easy. The trouble is that the important ones expire, every sub on a different date. The certificate that was current when you hired someone in March may have lapsed by October, and nobody tells you.
A few habits help:
- Track expiration dates, not just files. A folder of PDFs doesn't warn you about anything.
- Ask for renewals 30 days out. That's enough time for the sub to get the certificate from their agent.
- Check before every new job, not just at hiring.
- Keep everything in one place your whole team can see, so the person scheduling the sub knows whether they're cleared to work.
Running this checklist in BuildSuiteCrew
BuildSuiteCrew turns this checklist into something that runs itself:
- Subs upload their W-9, COI, workers' comp, and licenses once, and share them with every contractor they work for. It's free for subs, so they actually do it.
- Expiration dates are read from the documents automatically.
- Reminders go out 30 and 7 days before anything expires, and again when it does, to the sub and to your team.
- Your roster shows each sub as current, expiring, or expired at a glance.
- Send subcontract agreements for e-signature and keep the signed copy with the rest of their documents.
- Subs not on the app yet? Create an offline profile and upload their documents for them.
BuildSuiteCrew is $9.99/month for contractors, with a 14-day free trial, and free for subcontractors. See how it works.