Subcontractor Onboarding Checklist: The 10 Documents Every GC Needs

TL;DR: Collect 10 documents from every new sub before any work starts: signed subcontract, current ACORD 25 COI, W-9, workers' comp certificate (or exemption), state/trade license, EIN verification, banking info for ACH, OSHA 10/30 cards, MSA, and a signed safety acknowledgment. Enforce a strict no-paperwork-no-work rule because your leverage to demand documents disappears the moment the sub starts the job.

Every general contractor has the same tribal knowledge in their head: "here's what I need from a new sub before they can start." The problem is that tribal knowledge doesn't scale, doesn't transfer to new project managers, and doesn't survive the admin turnover that all GCs eventually face.

This post gives you that tribal knowledge as a written checklist. The 10 documents every sub should provide during onboarding, what each one is for, and the order to collect them in. Use it as a template for your own onboarding workflow and adapt the specifics to your state and project requirements.

Why Onboarding Matters More Than People Think

Bad onboarding is the root cause of almost every compliance problem GCs face later:

• Uninsured subs on site → bad onboarding (no COI verification upfront)
• 1099 scramble in January → bad onboarding (W-9 collected late or never)
• Missing licenses when auditors visit → bad onboarding (license never logged)
• Subs who disappear with disputes → bad onboarding (contract was never signed)

Onboarding is the moment you have maximum leverage over the sub. They want the work, they need your purchase order, they'll do the paperwork you require. Every day you let them start work without full documentation, your leverage decreases.

The rule: no work starts until every item on the checklist is on file. This is the most important compliance discipline you can build.

The 10-Document Checklist

1. Signed Subcontractor Agreement

Before anything else: a signed contract. The subcontractor agreement spells out scope, payment terms, change order procedures, insurance requirements, indemnification, dispute resolution, and everything else. Without it, you have a handshake, and handshakes don't survive disputes.

What to verify: Signed by an authorized party (not just a foreman), dated, both parties retain a copy, any attached exhibits (scope of work, drawings, specifications) referenced.

Common gotcha: Using a generic boilerplate subcontract that's missing construction-specific language around insurance requirements, AI endorsements, waiver of subrogation, and indemnification. Have a construction attorney draft your standard template.

2. Certificate of Insurance (COI)

The one document everybody knows about. A current ACORD 25 COI showing General Liability, Auto Liability, Workers' Comp, and Umbrella (if applicable).

What to verify:

• Limits meet your contract requirements
• Named insured matches the sub's legal entity name
• Effective and expiration dates cover the project
• Description of Operations references your Additional Insured endorsement, Primary and Non-Contributory language, and Waiver of Subrogation
• Your company is listed as Certificate Holder

See our detailed guide to reading a COI for exactly what to check.

3. Additional Insured Endorsement (CG 20 10 + CG 20 37)

Not just the COI. The actual endorsement pages from the sub's policy. Two forms:

• CG 20 10 for ongoing operations (while work is active)
• CG 20 37 for completed operations (after work is done)

Both matter. See our post on Additional Insured endorsements for the full explanation of why you need both and what to look for.

4. W-9 Tax Form

The IRS form that establishes the sub's TIN and tax classification. Without it, you can't issue a 1099 at year-end, and you may be on the hook for backup withholding.

What to verify:

• Legal business name matches the subcontract and COI
• TIN filled in (SSN for sole proprietors, EIN for entities)
• Federal tax classification marked (Individual, C-Corp, S-Corp, Partnership, LLC with specific classification)
• Signed and dated by an authorized person
• Certification section not crossed out or left blank

If the sub is a foreign person, they need a W-8BEN or W-8BEN-E instead of a W-9. See our post on W-9 vs W-8.

5. Workers' Compensation Certificate or Exemption

Proof the sub carries Workers' Comp for all employees, or an exemption certificate if the sub is a sole proprietor with no employees. This may be on the COI (most states) or require separate verification (monopolistic states. North Dakota, Ohio, Washington, Wyoming).

See our guide to monopolistic Workers' Comp states if you work in ND, OH, WA, or WY.

What to verify:

• Active coverage during project dates
• Correct entity name
• Employer's Liability limits meet contract requirements
• For exemption claims, a valid state-issued exemption certificate (not just the sub's word)

6. Contractor License (State + Local)

In most states, general contractors and specific trades (electrical, plumbing, HVAC) require state licenses. In some states (California, Florida, Arizona, Nevada, North Carolina, Louisiana, and others) enforcement is aggressive and hiring unlicensed subs can subject the GC to penalties directly.

What to verify:

• License number and classification
• Active status (not suspended, revoked, or expired)
• License covers the trade being performed
• Local permits / licenses where required (cities, counties, municipalities)

Most states have free online license lookup tools. Use them to verify directly rather than trusting what's on the sub's letterhead.

7. Business Entity Documentation

Proof the sub is a legitimate legal entity. For corporations and LLCs:

• Secretary of State registration (active / good standing)
• Federal EIN assignment letter (or equivalent)

For sole proprietors, a DBA filing or assumed name certificate in the sub's county is sufficient.

Why it matters: A sub operating as "Bob's Framing" without any underlying entity is a personal-liability risk. If something goes wrong, you're dealing with Bob the individual, not a company with assets or liability insurance.

8. OSHA Training Records (for trades where required)

For certain types of work, OSHA requires 10- or 30-hour training. Examples:

• OSHA 10 for general construction workers
• OSHA 30 for supervisors and project managers
• Silica training for work generating respirable silica dust
• Fall protection training for work above 6 feet

Your project may require specific OSHA certifications for all on-site workers. Collect cards or certificates during onboarding and file them with the sub's records.

9. Safety Program / Safety Plan

For larger projects, many GCs require subs to submit a written safety plan (Job Hazard Analysis, Accident Prevention Program, or equivalent) that describes how they'll manage safety on your site. This is especially important for higher-risk trades: excavation, demolition, roofing, high-steel, confined space.

This doesn't need to be a 50-page OSHA manual. A 2-page document covering the sub's safety meetings, PPE requirements, incident reporting, and key hazard controls is usually enough.

10. Banking and ACH Information

For payment processing. Collect the sub's banking information on a W-9-compatible form or an ACH authorization form, including:

• Routing number
• Account number
• Account type (checking / savings)
• Authorized signer

Security note: Treat banking info like W-9 data. It contains sensitive information and should be stored encrypted, never in email or shared drives. Require the sub to send this through your secure portal or directly to AP, never forwarded through project managers.

The Workflow: How to Make This Automatic

Having a checklist is one thing. Making it actually happen for every sub, every project, is the hard part. Here's the workflow that makes it routine:

Step 1: Sub Added to the System

The moment a sub is considered for a project, they're added to your compliance system. Not before (you don't want phantom records) and not after work starts either.

Step 2: Automatic Document Request

The system automatically sends the sub a welcome email with a secure upload link. The link lets the sub upload all 10 documents from a single interface without creating an account.

Step 3: Escalating Reminders

If the sub doesn't complete the upload within 48 hours, an automated reminder. At 5 days, a second reminder. At 10 days, the reminder goes to both the sub and the assigned PM.

Step 4: Work Authorization Gate

No PO, no access, no work authorization until the sub's record shows "compliant" in the system. This is the hard gate that makes the whole thing work.

Step 5: Ongoing Monitoring

Once the sub is compliant, the system watches expiration dates on COIs, licenses, and other time-bound documents. Automated alerts at 90, 60, 30 days before expiration, so you can collect renewals without missing a beat.

How PaperBoss Automates All of This

PaperBoss is built specifically for this workflow. You add a sub, pick which documents are required (COI, W-9, WC, license, custom doc types for your specific needs), and PaperBoss handles the rest: secure upload links, automated reminders, expiration tracking, compliance dashboards, and audit-ready reporting.

The core insight: compliance is a workflow problem, not a documentation problem. Everybody knows what documents they need. The hard part is collecting them, tracking them, and keeping them current across dozens of subs on multiple projects over years. Software that enforces the workflow makes the whole thing routine.

Start a 14-day free trial, no credit card required.

Frequently Asked Questions

Do I really need all 10 documents for every sub?

It depends on your project size, risk profile, and contract requirements. For small residential repair work, items 1 to 5 are typical minimums. For large commercial projects, you'll want all 10 plus possibly more (drug testing records, background check results, prevailing wage certifications, etc.). Err on the side of more when in doubt.

What if a sub refuses to provide some documents?

Either they're hiding something you need to know about, or they don't understand the requirement. Call them and explain why each document is required. If they still refuse, walk away. Any sub unwilling to complete basic compliance isn't worth the risk.

How long should I keep onboarding documents on file?

At minimum, for the duration of the project plus the applicable statute of repose (typically 6 to 10 years for construction in most states). For tax documents like W-9s, the IRS recommends keeping records for at least 4 years after the return due date. PaperBoss stores documents permanently by default.

Can I use DocuSign or Adobe Sign for the subcontract?

Yes. Electronic signatures are legally valid for subcontractor agreements in all US states under ESIGN and state equivalents. DocuSign/Adobe Sign/Dropbox Sign are all widely used and accepted in construction.

What about MSAs and project-specific agreements?

A Master Service Agreement (MSA) can cover the general terms once, with project-specific work orders or change orders for each individual job. This streamlines onboarding for subs you work with repeatedly. They sign the MSA once, and each new project just needs the work order and updated insurance certs.

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This article is for educational purposes only and does not constitute legal or insurance advice. Consult a construction attorney to develop your specific onboarding documentation requirements.