What is a certificate of insurance (COI) for contractors?

A certificate of insurance is a one-page document — typically an ACORD 25 form — that proves a contractor has active insurance coverage. It shows coverage types, policy limits, effective dates, and identifies the certificate holder. GCs require COIs from subcontractors before allowing work to begin on a job site.

What insurance do subcontractors need for GC jobs?

Most GCs require commercial general liability ($1M per occurrence, $2M aggregate minimum), workers' compensation at statutory limits, and commercial auto ($1M combined single limit). Many also require umbrella/excess liability and specific endorsements like additional insured status and waiver of subrogation.

What does 'additional insured' mean on a COI?

Additional insured is a policy endorsement that extends your liability coverage to the GC for work you perform on their project. It means if a claim arises from your work, the GC can make a claim under your policy. This is different from just being listed as the certificate holder — it requires an actual endorsement on your policy, not just a note on the ACORD form.

How quickly can contractors get a certificate of insurance?

Most insurance agents can issue a new COI within 1-3 business days. Adding endorsements like additional insured or waiver of subrogation may take longer. The bottleneck is usually the contractor requesting it too late — give your agent 3-5 business days before the job starts, not the night before.

The Subcontractor's Guide to Certificates of Insurance: What GCs Actually Want

You won the bid. The GC sends over the subcontract agreement. Buried in section 12 is the insurance requirements page. It lists coverage types, minimum limits, required endorsements, and a deadline to provide certificates. Miss any of it, and you don't start work.

This is where a lot of subcontractors lose time, money, and sometimes the job. Not because they don't have insurance, but because the paperwork isn't organized, the endorsements aren't in place, or they're scrambling to get a certificate issued the day before mobilization.

What a GC Actually Needs From You

When a general contractor asks for your "insurance," they're asking for a specific document: an ACORD 25 Certificate of Liability Insurance. It's a one-page standardized form that summarizes your coverage. But the form itself is just the surface.

Commercial General Liability (CGL). Minimum $1,000,000 per occurrence and $2,000,000 aggregate. Larger projects often require $2M/$5M or higher. Your CGL needs to be occurrence-based, not claims-made, unless the GC specifically allows it.

Workers' Compensation. Statutory limits for the state where the work is performed. Non-negotiable on virtually every commercial job. Even if your state doesn't require workers' comp for solo operators, most GCs do.

Commercial Auto. $1,000,000 combined single limit. Required if you or any employees drive to the job site. Covers owned, hired, and non-owned autos.

Umbrella / Excess Liability. Many GCs require $1M-$5M in umbrella coverage on top of your CGL, auto, and workers' comp. This is where smaller subs often fall short.

The Endorsements That Trip People Up

Having the right coverage limits is table stakes. The endorsements are where subcontractors get rejected.

Additional Insured. The GC must be listed as an additional insured on your CGL policy. This is the most common requirement and the most common point of confusion. Being named as the certificate holder on the ACORD form does not make someone an additional insured. That requires an actual endorsement on your policy. Your insurance agent needs to add this.

Waiver of Subrogation. This prevents your insurance company from going after the GC to recover money they paid on a claim from your work. Most GC contracts require this on both CGL and workers' comp.

Primary and Non-Contributory. This means your insurance pays first, before the GC's policy kicks in. Without this language, the GC's insurer might argue both policies should share the loss.

30-Day Notice of Cancellation. The GC wants to know if your policy gets cancelled. Standard ACORD forms include cancellation notice language, but some GCs require a specific endorsement guaranteeing 30 days' written notice.

The Real Problem: Timing and Organization

Here's what actually happens on most jobs:

Sub wins the bid on a Thursday
GC sends the subcontract on Friday with insurance requirements
Sub reads it Monday, realizes they need additional insured and waiver of subrogation endorsements they don't have
Sub calls their insurance agent Monday afternoon
Agent says endorsements take 3-5 business days
GC wants the certificate by Wednesday to start work Monday
Everyone is stressed, the start date may slip, and the GC is questioning whether this sub has their act together

The contractors who never have COI problems do two things differently:

They keep standard endorsements in place year-round. If you regularly work as a subcontractor, having additional insured, waiver of subrogation, and primary/non-contributory endorsements as standing features of your policy means you can issue a compliant certificate same-day for any GC. The incremental premium cost is small compared to the jobs you'll win by being ready.

They keep their documents accessible. When a GC asks for your COI at 7 AM from a job site, you need to produce it from your phone. Every insurance certificate, policy declaration page, and endorsement should be digitized and instantly retrievable.

What to Have Ready Before You Need It

Build a compliance packet you can send to any GC within minutes:

Current ACORD 25 certificate with all standard endorsements
Copy of your CGL declarations page showing limits and coverage terms
Workers' comp certificate or state exemption
Commercial auto certificate
Umbrella/excess certificate if you carry it
Current contractor license
W-9
Surety bond certificate (if applicable)

If you can send this complete packet as a single email or shared link, you've differentiated yourself from 90% of subcontractors who take days to assemble the same information.

When Certificates Expire Mid-Project

You're six months into a commercial project, your GL policy renews, and the new policy has a new certificate. The GC's compliance team flags that the certificate on file has expired. Work stops until you provide an updated cert.

This happens constantly, and it's entirely preventable with a system that tracks your policy expiration dates and reminds you to send updated certificates to active GCs before the old ones expire.

The Bottom Line

Certificates of insurance aren't complicated. They're just easy to neglect until the moment they become urgent. The subcontractors who win more GC work aren't the ones with the cheapest bids. They're the ones who send a complete, compliant insurance packet before they're asked, who never have a gap in coverage, and who can produce any document from their phone on a job site.