What is an additional insured endorsement? (CG 20 10 vs CG 20 38)

Why do general contractors require additional insured status?

When a subcontractor’s work causes bodily injury or property damage, the general contractor is frequently named in the resulting claim or lawsuit. Being a named additional insured on the sub’s commercial general liability policy means the sub’s carrier can defend and indemnify the GC for those claims—shifting the cost to the party whose work created the risk, rather than to the GC’s own policy. Pairing additional insured status with primary and non-contributory language is what makes that risk transfer effective.

CG 20 10 vs CG 20 37 vs CG 20 38

The most common additional insured endorsements are ISO forms. Knowing which one is attached—and its edition date—tells you what is actually covered:

• CG 20 10 — Ongoing operations.Adds the GC as an additional insured for liability arising out of the subcontractor’s ongoing operations, i.e., while the work is in progress.
• CG 20 37 — Completed operations.Extends additional insured status to the products-completed operations hazard—claims that arise after the work is finished. This is critical for construction defect exposure that surfaces later.
• CG 20 38 — Blanket, ongoing operations. Automatically grants additional insured status to any party the named insured is required to add by written contract, without scheduling each one by name. It generally covers ongoing operations, so a completed-operations form is often still required alongside it.

Because CG 20 10 (ongoing) and CG 20 37 (completed) cover different phases, many contracts require both. A blanket CG 20 38 simplifies administration but does not, by itself, supply completed-operations coverage.

What does Wardly check?

On each certificate of insurance, Wardlylooks for whether the additional insured box is marked and whether the description box references the expected endorsement forms—then flags it against the requirement you set (for example, “additional insured for ongoing and completed operations, CG 20 10 and CG 20 37”). It applies the same check to every subcontractor and grades the certificate A–F.

Common mistakes

• Treating the certificate holder line as additional insured status—they are not the same thing.
• Accepting ongoing-operations coverage only, leaving a gap for completed-operations (defect) claims.
• Relying on an “ADDL INSD” checkbox without confirming the underlying endorsement form and edition date.
• Forgetting that an additional insured endorsement works best alongside waiver of subrogation and primary and non-contributory wording.

Where to go next

Endorsement requirements are easy to write into a contract and hard to verify by hand on every certificate. Wardly automates that verification for free. If you’re evaluating tools, compare it with Jones on the comparison hub.

This is general information, not legal or insurance advice.