What additional insured status actually does
Adding a party as an additional insured extends certain protections of the subcontractor's general liability policy to that party — typically the general contractor and sometimes the project owner — for liability arising out of the subcontractor's work. It does not make the additional insured a named insured on the whole policy.
The specific protection depends entirely on the endorsement form attached to the policy — most commonly ISO CG 20 10 (Additional Insured — Owners, Lessees or Contractors) for ongoing operations, and ISO CG 20 37 for completed operations — which is why the endorsement number matters more than the label "additional insured" on a certificate.
Which endorsement actually applies
Additional insured: three real paths, not one generic box to check
Named, specific party
CG 20 10 — ongoing operations
CG 20 37 — completed operations
Scheduled — names one obligee. Re-issued every time a new party needs AI status.
Automatic, by written contract
CG 20 33 — direct contract privity
CG 20 38 — extends to upstream parties
Blanket — no per-project reissue. Applies automatically whenever a contract requires AI status.
Government agency issued a permit
CG 20 12 — state or governmental agency
Only when the agency issued a permit or authorization — not when the agency is the project owner (that still uses CG 20 10/CG 20 37).
A contract naming a specific form by number generally isn't satisfied by a different form covering the same party in practice — confirm which of these three a specific project actually requires before assuming a standard endorsement fits.
Why a certificate of insurance isn't proof by itself
A certificate of insurance is a summary document, not a policy or an endorsement — it does not by itself add anyone as an additional insured. The actual endorsement must be issued by the carrier and attached to the policy.
A general contractor that relies only on a certificate, without confirming the endorsement was actually issued, can discover after a loss that the expected coverage was never in place.
Primary and noncontributory wording
Many contracts also require the subcontractor's coverage to be "primary and noncontributory" — meaning the sub's policy responds first, ahead of the general contractor's own insurance, rather than the two policies sharing the loss.
This is a separate endorsement from additional insured status and is commonly requested alongside it, along with a waiver of subrogation.
Completed operations coverage
Standard additional insured endorsements can be limited to "ongoing operations," meaning coverage applies only while the subcontractor's work is in progress — not after the project is finished. A separate "completed operations" additional insured endorsement (ISO CG 20 37) is needed to extend that protection after the work is done.
Contracts on projects with long-tail liability exposure — construction defect claims can surface years later — commonly require this broader endorsement specifically.
Coverage remains subject to underwriting and the issued policy
Whether a specific endorsement is available, and on what terms, depends on the carrier underwriting the subcontractor's policy — this post explains how these endorsements typically work, not a guarantee of availability for any specific account.
A real example: when a blanket endorsement wasn't accepted
Blanket additional insured endorsements satisfy many contracts, but not every certificate holder will take them. One of our general contractor clients had a California city's building permit held up because the city wanted to be listed by name on scheduled endorsements, in its own required language, for both additional insured status and the waiver of subrogation. Confirming the city's exact requirements first, and then ordering the matching endorsements from the carrier, is what got the permit moving again (case study 12).
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Frequently asked questions
7 questions — start typing to filter
Does a certificate of insurance prove additional insured status?
No. A certificate is a summary document. The actual additional insured endorsement must be issued by the carrier and attached to the policy for the status to apply.
What's the difference between ongoing and completed operations additional insured coverage?
Ongoing operations coverage applies only while the subcontractor's work is in progress. Completed operations coverage extends protection after the work is finished, which matters for claims that surface later, such as construction defects.
What does "primary and noncontributory" mean?
It means the subcontractor's policy responds first to a covered loss, ahead of the general contractor's own insurance, rather than the two policies sharing the claim. It's a separate endorsement from additional insured status.
Who typically requests additional insured status?
General contractors commonly require it from subcontractors, and project owners or lenders sometimes require it from the general contractor, depending on the contract.
Does additional insured status cost extra?
Often yes, though the cost varies by carrier and endorsement form — some carriers include limited blanket additional insured wording at no extra charge for ongoing operations, while completed operations endorsements more often carry an additional premium.
Can a subcontractor be added as additional insured on the GC's policy instead?
Sometimes, but this is less common and doesn't replace the subcontractor's own coverage obligations — most contracts specifically require the sub to name the GC as additional insured on the sub's own policy, not the reverse.
How long should completed operations additional insured coverage last?
It depends on the contract and the applicable statute of repose for construction defect claims in that state, which can run several years — confirm the specific duration required in the written contract rather than assuming a standard timeframe.