Additional Insured Endorsements: What GCs Require From Their Subs

Quick answer: An additional insured endorsement extends your general liability policy to protect the general contractor as if they were a named insured, so their defense and damages for a claim arising from your work come out of your policy. GCs almost always require CG 20 10 (ongoing operations) and CG 20 37 (completed operations), plus primary and non-contributory wording and a waiver of subrogation, all shown on your certificate of insurance.

What is an additional insured endorsement?

Your general liability policy protects you, the named insured. An additional insured (AI) endorsement is an add-on that extends that same policy to also protect another party — here, the general contractor who hired you. When a claim arises out of your work, the GC can tap your coverage for their defense and any damages, instead of burning through their own policy.

Why do GCs insist on this? Because when a sub causes a loss, the GC often gets named in the lawsuit too. Requiring AI status pushes the financial responsibility down to the party who actually created the risk — you and your insurer. It's a standard, reasonable part of nearly every subcontract in California.

CG 20 10 vs. CG 20 37: the two endorsements that matter

These are the two most common ISO additional insured forms, and GCs usually want both. They cover different points in time:

Here's why both matter. Say you frame a building. A claim during construction — a worker hurt while you're on site — falls under ongoing operations (CG 20 10). But if a defect surfaces two years after completion and someone is injured, that's a completed operations claim — and only CG 20 37 extends the GC's protection to that later exposure. Provide only CG 20 10 and you've left a gap the GC's contract almost certainly prohibits.

A quick word on editions: older forms like the CG 20 10 (2004) blend some completed-ops language, but the market standard is to supply both CG 20 10 and CG 20 37 so the ongoing and completed phases are cleanly covered. Read the subcontract — it usually names the forms it wants.

Primary and non-contributory: whose policy pays first

Being an additional insured isn't enough on its own. GCs also require primary and non-contributory wording. In plain terms:

• Primary means your policy pays first when a covered claim arises from your work — the GC's insurance isn't tapped until yours is exhausted.
• Non-contributory means your insurer can't demand that the GC's insurer chip in on a pro-rata basis.

Without this language, insurers can fight over who pays what, and the GC could end up sharing a loss you caused. GCs eliminate that argument by requiring your policy to sit in the primary position.

Waiver of subrogation: no clawbacks against the GC

Subrogation is your insurer's right to recover money it paid on a claim by going after whoever was responsible. A waiver of subrogation endorsement gives up that right against the general contractor. So if your insurer pays a claim, it agrees in advance not to turn around and sue the GC to get it back. GCs require this so they aren't chased by your carrier after a loss on their own project.

The certificate of insurance ties it together

You prove all of this with a certificate of insurance (COI) — a one-page snapshot of your coverage that your agent issues, usually naming the GC as certificate holder and additional insured and referencing the endorsement forms. But note the fine print on every COI: it's evidence, not the policy itself. The actual protection comes from the endorsements attached to your policy. That's why GCs increasingly ask to see copies of the CG 20 10 and CG 20 37 forms, not just the certificate. Make sure your policy truly carries them — a COI that references coverage you don't actually have is a problem waiting to surface at claim time.

Getting it right before you sign

Before you sign a subcontract, read the insurance exhibit and match it to your policy. Confirm you have blanket or scheduled AI endorsements (CG 20 10 and CG 20 37), primary and non-contributory wording, and waiver of subrogation available. Many carriers offer these on a blanket basis — automatically extending to anyone you're contractually required to add — which saves you from requesting a new endorsement for every job. If your policy can't deliver what the contract demands, better to fix it now than to lose the job at compliance review.

General information only, not legal or coverage advice. Endorsement availability and wording vary by carrier and edition; confirm with your agent and read your subcontract.