An additional insured endorsement is a modification to your commercial general liability policy that extends coverage to a third party, typically a general contractor, property owner, or developer who has hired you to perform roofing work. When you add someone as an additional insured on your policy, they gain the right to file a claim under your CGL if they are sued for bodily injury or property damage arising out of your work. This is one of the most common insurance requirements in construction contracts, and understanding how it works will save you from costly disputes.
The most widely used additional insured endorsements in construction are based on ISO forms. The two you will encounter most often are CG 20 10 (Additional Insured - Owners, Lessees or Contractors - Scheduled Person or Organization) and CG 20 37 (Additional Insured - Owners, Lessees or Contractors - Completed Operations). CG 20 10 provides additional insured status for ongoing operations, meaning claims that occur while your crew is still on the job site. CG 20 37 extends that protection into the completed operations period, covering the additional insured for claims that arise after you finish the work. Most GCs and project owners will require both endorsements.
The scope of coverage provided to the additional insured is limited to liability caused in whole or in part by your acts or omissions. This is an important distinction. The additional insured endorsement does not give the GC blanket coverage under your policy for their own independent negligence. If a GC's own employee causes an accident unrelated to your roofing work, your policy will not respond to that claim. The endorsement only covers claims where your work is at least partially at fault.
Primary and noncontributory language is frequently required alongside the additional insured endorsement. When your policy is endorsed as primary and noncontributory, it means your insurer must pay first on any covered claim before the additional insured's own policy contributes. Without this language, the two insurers might dispute which policy should pay first, delaying the claim resolution. The ISO endorsement CG 20 01 or equivalent manuscript language is used to add primary and noncontributory status.
Waiver of subrogation is another endorsement commonly bundled with additional insured requirements. A waiver of subrogation prevents your insurer from seeking reimbursement from the additional insured after paying a claim on your policy. Without this waiver, your insurer could pay a claim and then sue the GC to recover its costs, which defeats the purpose of the additional insured arrangement from the GC's perspective.
From a practical standpoint, you should expect to provide additional insured endorsements on virtually every commercial roofing project. The cost is typically modest, often $25 to $100 per endorsement or included at no additional charge in your policy. Your insurer or broker will issue a certificate of insurance (COI) along with the endorsement, which you send to the requesting party as proof of coverage. Make sure the COI accurately reflects your policy limits, effective dates, and the specific endorsements attached.
Review every additional insured request carefully before agreeing to it. Some contracts contain indemnification language that attempts to make you responsible for the GC's own negligence, which can create coverage gaps if the endorsement does not match the contractual obligation. Have your broker or attorney review contracts that contain broad-form indemnity clauses, especially in states that have anti-indemnity statutes limiting the enforceability of such provisions. Getting this right before the project starts is far easier than resolving a coverage dispute after a claim.