A per-project aggregate endorsement modifies your general liability policy so that your aggregate limit applies separately to each project rather than being shared across all your projects for the entire policy year. Without this endorsement, a single large claim on one project can exhaust your aggregate and leave every other project you are working on effectively uninsured for the remainder of the policy period. For roofing contractors running multiple jobs simultaneously, this endorsement is not optional — it is essential.
Understanding the Aggregate Problem
A standard GL policy has two primary limits: a per-occurrence limit (typically $1,000,000) and a general aggregate limit (typically $2,000,000). The per-occurrence limit caps what the policy pays for any single claim. The general aggregate caps the total the policy pays for all claims during the policy period — usually one year.
Here is the problem. You are a roofing contractor running five jobs simultaneously. A $900,000 completed operations claim hits from a job you finished three months ago, and a $700,000 property damage claim occurs on a current project. Both claims are within the $1,000,000 per-occurrence limit, so the policy pays each one. But combined, they total $1,600,000 against your $2,000,000 aggregate. You now have only $400,000 in aggregate remaining for the rest of the policy year — across all of your active projects.
If a third claim occurs — even a modest $500,000 claim — your policy can only pay $400,000 of it. You are personally responsible for the remaining $100,000. And every GC and property owner on your active projects is now exposed because your aggregate is nearly exhausted.
How Per-Project Aggregate Solves This
With a per-project aggregate endorsement (ISO form CG 25 03), your $2,000,000 aggregate applies independently to each project. The $900,000 completed operations claim consumes aggregate only for that specific project. Your other four active projects each still have a full $2,000,000 aggregate available. A claim on Project B does not reduce the aggregate available for Projects A, C, D, or E.
This is critically important for roofing contractors because your work inherently involves multiple concurrent projects with significant exposure at each one. A residential reroofing company might have 8 to 12 active jobs at any given time. A commercial roofing company might have 3 to 5 large projects running simultaneously, each with millions of dollars in property exposure below the roof.
Why GCs Require It
General contractors understand the aggregate problem, which is why most commercial subcontracts require per-project aggregate coverage. The GC's risk manager wants assurance that claims on your other projects will not deplete the coverage available for their project. The certificate of insurance must specifically indicate "per project" in the aggregate section — if it shows "per policy," the GC will reject it.
On the ACORD 25 certificate, the per-project aggregate is indicated by checking the "project" box next to the general aggregate limit. If your policy does not carry the per-project endorsement, your agent cannot check that box — and the GC will flag the deficiency.
Cost
The per-project aggregate endorsement typically adds 5% to 15% to your GL premium. For a roofing contractor paying $12,000 per year for GL, that is $600 to $1,800 — a modest cost relative to the protection it provides. Some carrier programs designed for contractors include per-project aggregate as a standard feature at no additional charge.
Per-Project vs. Per-Location
Do not confuse per-project aggregate with per-location aggregate (CG 25 04). Per-location applies the aggregate separately to each physical location where you perform work, which can be useful for maintenance contractors who service the same buildings repeatedly. Per-project applies the aggregate to each distinct project under a separate contract. For roofing contractors performing discrete project-based work, per-project is the correct endorsement and the one GCs require.
Implementation
Request the per-project aggregate endorsement at policy inception. Adding it mid-term is possible but creates a gap — projects started before the endorsement effective date may not benefit from per-project treatment. If you do any commercial work or work under subcontracts, make this endorsement a standard part of your GL program from day one. It eliminates a common certificate deficiency, satisfies GC requirements, and protects your business from the aggregate erosion that can occur during an active roofing season.