Do I Need a COI from Contractors?

Yes, in most cases where a subcontractor performs work on your site, and always when your contract, owner, or lender requires it. A certificate of insurance (COI) is the standard proof that a sub carries active liability coverage before mobilization. If you are hiring a one-off labor subcontractor, the answer is almost always yes. If you are buying materials from a vendor who never sets foot on the job, you can often skip it. The rest of this guide walks through when a COI is mandatory, when it is best practice, and when it is genuinely optional.

When is a COI legally or contractually required?

A COI becomes required when something in writing says it does, not because every state mandates one for every trade.

Written subcontract or purchase order. Most standard subcontract agreements include an insurance exhibit listing minimum coverage types, limits, and endorsement requirements. If your agreement references insurance, you need a COI (and usually endorsement PDFs) before the sub starts work.

Owner or prime contract pass-through. If your agreement with the project owner requires you to flow insurance requirements down to every subcontractor, you are contractually obligated to collect certificates that match those terms.

Lender, surety, or bonding requirements. Construction loans and bonded public work often require documented proof that every tier of contractor carries required coverage. Missing certificates can delay draws, bond releases, or final acceptance.

Licensed-trade and statutory contexts. Some states tie contractor licensing to maintaining specific insurance types. That does not always mean you must collect a COI, but it strengthens the case when the sub performs regulated work on your site.

Once you have decided a COI is required, the next question is what to verify on it. See subcontractor insurance requirements: what GCs should verify for the checklist.

When is a COI best practice but not strictly required?

Informal arrangements, like a handshake with a painter for a bathroom remodel or a friend-of-a-friend electrician for a quick fix, often have no written insurance clause. Legally, you may not be obligated to collect a certificate.

GCs still request one anyway, for a practical reason: liability can flow back to whoever controls the site. If an uninsured subcontractor's employee is injured, or their work damages adjacent property, the GC is frequently the first party an owner, insurer, or attorney looks to. A COI does not prevent every claim, but it confirms the sub had active coverage on the date you cleared them, before crews mobilized.

This applies especially when:

• The sub brings employees or equipment onto your property
• You are the GC of record, even on a small residential job
• You have never worked with this sub before and have no other way to confirm coverage

Collecting a COI on a small job takes minutes. Reconstructing whether a sub was insured after an incident takes much longer.

When is a COI genuinely optional or lower risk?

Not every vendor relationship needs a certificate. Be honest about lower-risk scenarios rather than treating every supplier like a mobilizing subcontractor.

Delivery-only vendors. A lumber yard dropping a load at the curb, a ready-mix truck making a pour under your supervision, or a supplier delivering fixtures to the staging area: these vendors typically carry their own commercial policies, but they are not performing scoped subcontract work under your direction. Many GCs skip COIs here unless the contract or owner requires them for all vendors.

Material purchases with no site labor. Buying tile, fixtures, or equipment where the vendor never performs installation or sends workers onto the site is a different risk profile than hiring an installer.

Established vendors with zero site access. Corporate suppliers you order from by phone or portal, with no crews on your property, rarely need a COI in a typical residential or light commercial program.

When in doubt, check your owner contract and subcontract template. If neither mentions insurance for that vendor type, you likely have flexibility.

What happens if you skip it and something goes wrong?

The practical consequence is uncertainty at the worst moment. If a subcontractor is uninsured or underinsured and their work causes injury or property damage, the GC often faces questions about site control, hiring practices, and whether insurance requirements were enforced. Owners may withhold payment. Audits may flag missing documentation.

This is not a reason to fearmonger every small job. It is the trade-off you accept when you skip verification. You are betting that nothing goes wrong, or that the sub's coverage (if any) will respond without you needing proof on file.

Quick decision framework

Use this table as a starting point. Your contract and owner requirements always override informal judgment.

Require a COI if:

• The sub brings workers or equipment onto your property
• Your contract, owner agreement, or lender requires it
• You are the GC of record on a commercial or bonded project

Can likely skip if:

• The vendor delivers materials only and performs no labor
• No contract, owner, or lender requirement applies to that vendor type
• The vendor has no site access and no scoped work under your direction

Where to go next

If you are still building your understanding of what a COI actually is, start with What is a certificate of insurance (COI) in construction?. That guide explains what the document proves, what it does not, and how ACORD 25 fits mobilization workflows.

If you have decided you need certificates and want to know what to check, read Subcontractor insurance requirements: what GCs should verify for the field-by-field review checklist.

If you have a certificate in hand and want a quick validity check before mobilization, use our free COI approval checker to flag common certificate issues and get a coordinator-ready summary.