Primary and non-contributory is an endorsement on your general liability policy that dictates how your coverage interacts with the additional insured's own insurance when a claim is filed. When your policy is endorsed as primary and non-contributory, it pays first — before the additional insured's own GL policy — and it does not seek contribution from their policy. This is one of the most frequently required endorsements in commercial roofing subcontracts, and misunderstanding it costs contractors projects.
The Problem It Solves
Without primary and non-contributory language, when a claim is filed against both you and the GC (who is named as an additional insured on your policy), the two GL policies — yours and the GC's — would normally share the claim. Depending on the policy language, they might split the claim equally, prorate it based on limits, or follow an "other insurance" clause that creates ambiguity about which policy pays first.
GCs do not want this ambiguity. They do not want their own GL policy triggered by a claim arising from your work. Their loss history affects their premiums, their experience rating, and their ability to bid on projects. A claim paid by the GC's own policy — even one caused entirely by your operations — becomes part of their loss record. Primary and non-contributory language ensures that your policy absorbs the claim without involving the GC's coverage.
How It Works in Practice
Consider this scenario. Your crew is tearing off a built-up roof on a commercial project. During tear-off, debris falls and damages a tenant's vehicle in the parking lot below. The tenant sues the property owner (who hired the GC) and the GC (who hired you). Both the property owner and the GC are additional insureds on your GL policy.
With primary and non-contributory: Your GL policy pays the entire claim up to your per-occurrence limit. The GC's GL policy is not triggered and does not contribute. The GC's loss history is unaffected.
Without primary and non-contributory: Your GL policy and the GC's GL policy may share the claim under their respective "other insurance" clauses. The GC's policy pays a portion, the GC's loss history takes a hit, and the GC's next renewal premium increases. The GC blames you — rightly — for not carrying the endorsement they required.
The Endorsement Form
The ISO endorsement that provides primary and non-contributory status is CG 20 01 — Primary and Non-Contributory, Other Insurance Condition. Some carriers incorporate this language into their blanket additional insured endorsement rather than using a separate form. Either approach is acceptable as long as the certificate of insurance confirms the coverage. On the ACORD 25 certificate, the primary and non-contributory status is typically noted in the description of operations section with language such as: "The general liability policy is primary and non-contributory with respect to the additional insured as required by written contract."
Interaction With Your Umbrella
Primary and non-contributory applies to your primary GL policy. Your umbrella policy sits above the GL and responds after the GL limit is exhausted. However, for the umbrella to function properly for the additional insured, it must follow form — meaning it adopts the same primary and non-contributory terms as the underlying GL. If the umbrella does not follow form on this point, the additional insured may face a contribution argument at the umbrella layer. Confirm with your agent that both your GL and umbrella provide primary and non-contributory status.
Cost and Implementation
The primary and non-contributory endorsement typically costs $100 to $400 per year, and many contractor-focused GL programs include it at no additional charge. Like other contractual endorsements, the most efficient approach is to add it to your policy at inception on a blanket basis — automatically applying to any party you are required by written contract to name as additional insured on a primary and non-contributory basis. This eliminates mid-term endorsement requests and certificate delays.
If you perform any commercial roofing work, primary and non-contributory is not optional. Every major GC requires it. Every property owner's risk manager expects it. Add it to your GL program alongside blanket additional insured and blanket waiver of subrogation, and you will satisfy the insurance requirements in virtually every subcontract you encounter.