The additional insured requirement is one of the most important provisions in any construction subcontract. It's also one of the most frequently misunderstood and misverified requirements in the industry.
When it works correctly, additional insured status means that if a subcontractor's work causes an injury or property damage, the GC and owner are covered under the sub's policy. They don't have to rely solely on their own coverage. Defense costs are shared or shifted. The risk transfer actually happens.
When it doesn't work correctly, you get a claim, you tender it to the sub's carrier, and the carrier disputes the scope of your coverage. You're now in a coverage argument rather than a covered claim.
Certificate vs. Endorsement: Two Different Things
Certificate vs Endorsement
The most consequential misunderstanding in construction additional insured programs is treating the certificate of insurance as proof of additional insured coverage.
It isn't. The certificate is a summary document. It can note that additional insured status has been arranged, but it doesn't create that status and it doesn't specify the terms. The endorsement attached to the policy creates the actual coverage.
This matters because the endorsement terms determine whether your additional insured status is worth what you think it's worth. A blanket additional insured endorsement on the sub's policy may provide coverage in some circumstances and not others. The ISO CG 20 10 and CG 20 37 endorsements are the most commonly required forms in construction, but there are many variations, and the differences are significant.
If your subcontract says "additional insured coverage shall be provided via ISO CG 20 10 11 85 or equivalent" and the sub's policy uses a modified form that limits coverage to ongoing operations, your completed operations exposure is unprotected.
What Construction Subcontracts Should Require
A properly constructed additional insured requirement in a subcontract specifies several things beyond just "the GC shall be named as additional insured."
The covered entities. The GC's legal entity name, the owner's legal entity name, and any other upstream parties specified in the prime contract should all be named. Vague language like "the general contractor and owner" creates disputes over who is actually covered when the legal entity names on the claim documents don't match what's reflected on the endorsement.
The endorsement basis. Primary and non-contributory language means the sub's policy pays first before the GC's policy is touched. Without it, both carriers may dispute who pays first, and you end up with a coverage coordination dispute in addition to the underlying claim.
Both operations. Completed operations coverage protects you after the work is done. Many subcontracts specify ongoing operations coverage but neglect to require completed operations, which leaves the GC exposed to latent defect claims that surface after project completion.
The policy period. Additional insured status needs to extend through the completed operations tail period, not just through the project end date.
What Goes Wrong in the Verification Step
Knowing what your subcontract requires is half the program. The other half is verifying that what came in on the COI actually delivers it.
| What the Subcontract Requires | Common Verification Failure |
|---|---|
| Primary and non-contributory AI status | COI notes "additional insured" without confirming P&NC basis |
| Completed operations coverage | Only ongoing operations confirmed; tail period not verified |
| Specific legal entity named | Trade name or abbreviation accepted instead of legal entity |
| Specific endorsement form | Generic "additional insured endorsement" accepted without form verification |
| Owner and GC both named | Only GC checked; owner omitted |
Most of these failures don't surface during the project. The project wraps up, everyone moves on, and the gaps remain invisible until a claim surfaces, sometimes years later on a completed operations basis.
The Primary and Non-Contributory Problem
Primary and non-contributory is the provision that determines which policy pays first when both the GC's and sub's policies could respond to a claim.
Without P&NC language, both carriers can argue that the other's policy should contribute. This is called contribution, and it's the mechanism that turns a clear claim into a prolonged coverage dispute. Your own premiums and loss history can be affected while the dispute continues.
With P&NC language in place and confirmed on the endorsement, the sub's policy responds first. Your policy is not triggered until the sub's limits are exhausted. That's the risk transfer the subcontract was designed to create.
Verifying P&NC on the COI alone is not sufficient. The certificate remarks section may note it, but what matters is whether the actual endorsement attached to the policy provides it. For high-value subcontractors and significant scopes of work, requesting the endorsement form directly is reasonable and appropriate.
How Bramble Addresses Additional Insured Verification
Bramble reads the additional insured requirements directly from your executed subcontracts and compares them against the COI data at the clause level. When a COI comes in for a subcontractor, Bramble identifies not just whether an additional insured is listed, but whether the specific entities required by that subcontract are present and whether the endorsement basis is reflected.
Gaps in additional insured compliance surface before the project begins rather than after a claim is filed. Your team knows what's confirmed and what still needs to be resolved, organized by project and subcontractor.
That's the difference between a compliance program that looks thorough and one that actually is.
Book a demo to see how Bramble handles additional insured verification
Frequently Asked Questions
What is the difference between an additional insured and a certificate holder in construction? A certificate holder receives a copy of the certificate but has no coverage under the policy. An additional insured has actual coverage rights under the policy, including the right to tender a claim directly to the insurer.
What does primary and non-contributory mean in a subcontract? It means the subcontractor's policy responds first to a covered claim before the GC's or owner's policy is triggered. Without this language, both policies may contribute to the claim, creating disputes over allocation.
What endorsement forms are standard for construction additional insured requirements? ISO CG 20 10 (ongoing operations) and CG 20 37 (completed operations) are the most commonly referenced forms. Some contracts specify the 11 85 or 07 04 editions, as the coverage scope varies between editions.
Can a GC rely on a COI to confirm additional insured status? The COI can reflect that additional insured arrangements have been made, but it does not create coverage and doesn't specify endorsement terms. For significant scopes of work, requesting the actual endorsement from the sub's broker is appropriate.
How long should completed operations additional insured coverage extend? This depends on the applicable statute of repose in the project's jurisdiction, but three to ten years is a common range. The subcontract should specify the required tail period and the COI should be verified against that requirement.