Subcontractor Onboarding Checklist: 12 Documents to Collect
The first week with a new subcontractor sets up the next year of paperwork. Collect what you need before they mobilize and you have a clean file. Collect it piece by piece after the crew is on site, and you will spend the project chasing a missing W-9, an expired certificate or a contract nobody signed. Here are the 12 documents to gather, the order that matters, and how to keep track of who still owes what.
Every new subcontractor should give you twelve things: a W-9 and license, a certificate of insurance with the endorsements and broker contact behind it, a signed subcontract with scope and price on record, safety and emergency contacts, and payment setup. Collect the tax, insurance and contract items before anyone comes to site, and the payment items before the first invoice.
Key Takeaways
- Collect in stages: tax, insurance and contract before site access, payment setup before the first invoice.
- The legal name on the W-9, the subcontract and the certificate of insurance should all match.
- Ask for endorsements, not just certificates. A ticked box on a COI is not coverage.
- Give each document one owner, and track expiration dates from day one.
1. Why a Checklist Pays for Itself
Missing paperwork has a cost that shows up later, usually at a bad moment. An uninsured sub on site puts your own policy and audit at risk: a workers' compensation carrier can charge premium for work done by subcontractors who could not show coverage, which our audit formula guide walks through. A missing W-9 turns tax season into a scramble, since the IRS instructions for tax years after 2025 call for a 1099-NEC for each person you paid at least $2,000 during the year (IRS instructions for Forms 1099-MISC and 1099-NEC, retrieved September 2026). And an unsigned subcontract means you are arguing about payment terms with nothing in writing.
A checklist does not add work. It moves the work to the moment when the subcontractor is most willing to cooperate, which is before they have started.
2. The 12 Documents, Explained
Not every item applies to every job. A landscaping sub on a small property may not need a safety program, and a remote trade may not need a license. Decide once, per trade, what is required, then apply it the same way every time.
Identity and tax
1. Completed Form W-9
The W-9 gives you the subcontractor's legal name, business structure and taxpayer identification number. Check that the name matches the entity on the subcontract and the certificate of insurance, because a mismatch between those three is where later problems start.
2. Business or trade license
Where your state or city requires a contractor or trade license for the work, collect the license number and expiration date, and confirm it on the issuing agency's lookup. Put the expiration date in your tracking list so renewals don't go unnoticed.
Insurance
3. Certificate of insurance for every required coverage
Request an ACORD 25 that shows each coverage your contract requires, typically general liability, auto liability, workers' compensation and umbrella or excess, with limits and dates that cover the project. Our guide to requesting a COI includes email templates.
4. The endorsements behind the certificate
A checked box on the certificate is not an endorsement. If your contract requires additional insured status, a waiver of subrogation or primary and non-contributory wording, ask for the endorsement forms themselves.
5. Insurance broker contact details
Get the agent's name, email and phone number directly. You will want them for verification, for renewals and for corrections, and requests that go to the broker usually come back faster and cleaner than ones routed through the subcontractor.
Contract
6. Signed subcontract or master agreement
No work, no deposit, no site access until this is signed by both parties. Keep the signed copy where everyone who approves payment can find it, since the payment terms, retainage and insurance clauses live here.
7. Non-disclosure agreement, if the project needs one
Required on projects with confidential owners, tenants or facilities. Collect it with the subcontract so it isn't forgotten once the crew is already on site.
8. Scope, schedule and contract value on record
Record the agreed price and scope in a form your accounting team can compare invoices to. This number, plus approved change orders, is what every invoice will be checked against.
Safety and site access
9. Safety program or site safety acknowledgment
Collect whatever your contract or owner requires: a written safety program, a signed site safety acknowledgment, or proof of required training. Ask for what you will actually enforce, not a generic packet.
10. Key personnel and emergency contacts
Name the subcontractor's project contact, superintendent and an after-hours number. If something goes wrong on site, you want to know who to call without digging through emails.
Payment setup
11. Invoicing and lien waiver instructions
Tell the subcontractor how to invoice (which project, which invoice type, where to send it) and which lien waiver forms you need with each payment. Sending this up front prevents the most common invoice rejections later.
12. Payment details or authorization
If you pay by ACH or another electronic method, collect the authorization form and verify the account details through a known contact before the first payment, not by replying to the email that delivered them.
For what insurance limits to ask for by trade, see subcontractor insurance requirements by trade. For the endorsements in item 4, read additional insured vs. certificate holder.
3. When to Collect What
Trying to collect all twelve before signing slows everything down, and collecting them all after starting removes your leverage. Three stages work better:
| Stage | Collect |
|---|---|
| Before you sign the subcontract | W-9, license, certificate of insurance with endorsements, broker contact details. |
| Before anyone comes to site | Signed subcontract or master agreement, NDA if needed, safety acknowledgment, key personnel and emergency contacts, scope and contract value on record. |
| Before the first invoice is approved | Invoicing and lien waiver instructions, payment authorization, and a current certificate confirmed for the billing period. |
Make the gates explicit in your subcontract: no site access without a current certificate, and no invoice approved without the items in the third row. Subs accept rules that apply to everyone. What they resent is a rule that appears after they are already on the job.
4. Who Chases What, and When
Onboarding stalls when everyone assumes someone else is following up. Give each document type one owner and one deadline:
- Project manager: the signed subcontract, scope and contract value, key personnel.
- Accounting: W-9, payment authorization, invoicing and lien waiver instructions.
- Risk or safety lead: certificate, endorsements, license, safety acknowledgment.
Then keep the file alive. Insurance expires every year and licenses renew on their own schedules, so record every expiration date when the document comes in and start asking for the renewal about 60 days before it lapses. Our guide to requesting a COI from a subcontractor has copy-and-paste emails for new, corrected and renewal certificates.
5. Running the Checklist in SubDoc
A shared spreadsheet handles a short list for a few subs. It starts to slip once you are onboarding across trades and projects. For teams that want the checklist to run itself, this is how SubDoc handles it.
- You build a requirement template once per trade, covering insurance limits and endorsements plus documents such as a W-9, license and signed agreement, and assign it to each new vendor.
- The vendor gets one link to upload everything, with no account, and their broker can upload the certificate on their behalf. SubDoc reads the certificate and checks each coverage against your requirements.
- For the subcontract, you can send it for e-signature from SubDoc, and the signed copy files itself on the vendor's checklist.
- Your team is alerted before certificates expire, and you can send vendors a reminder from the vendor page in one click.
Frequently Asked Questions
At minimum: a completed W-9, any trade or business license your jurisdiction requires, a certificate of insurance showing the coverages your contract requires, the endorsements that back it up (such as additional insured), and a signed subcontract. Safety acknowledgments, key contacts and payment instructions can follow, but should all be in before the first invoice is approved.
Yes, collect one from every sub up front. The IRS instructions for tax years after 2025 say to file Form 1099-NEC for each person you paid at least $2,000 during the year, and you rarely know in advance which subs will cross that line. The W-9 also gives you the taxpayer identification number you need if backup withholding ever applies.
Set a firm rule and apply it to everyone: no site access until the certificate of insurance, required endorsements and signed subcontract are on file. Everything else, such as payment setup and lien waiver instructions, should be due before the first invoice is approved rather than before day one.
Give each document type one owner. Project managers usually own the subcontract and scope. Accounting owns the W-9 and payment setup. Whoever manages risk or safety owns insurance and safety paperwork. What matters is that nobody has to guess who is chasing the missing item.
Insurance on every policy renewal, which is usually annually, and ideally 60 days before each expiration so there is time to get a new certificate. Licenses on their own renewal dates. A W-9 when the subcontractor's name, business structure or tax ID changes. The subcontract for each project, or for the term of a master agreement.
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