What Is General Liability Insurance in Construction? The Policy That Stops Third-Party Claims

Commercial general liability insurance — almost always abbreviated CGL — is the core commercial liability coverage that every construction business carries. It pays when a third party (someone other than the insured's own employees) is injured or has their property damaged as a result of the insured's operations. Without CGL, a single significant incident — a passerby injured by falling debris, a neighboring property damaged by site work, a claimant injured on the completed project — could produce an uninsured judgment large enough to end the business.

CGL is the largest single insurance premium for most construction companies, and understanding what it covers is essential for anyone responsible for construction insurance. It's also the policy most commonly referenced in contracts — the general contractor requiring specific CGL limits from subs, the owner requiring additional-insured endorsements, the surety evaluating coverage as part of underwriting.

What CGL Covers

A CGL policy is structured in coverage parts, each covering a specific type of loss. The standard ISO CGL form includes:

Coverage A is the most important for construction. It covers injuries and property damage caused by the insured's ongoing operations (work in progress) and by completed operations (work that's been finished and turned over). A person hurt walking past the construction site falls under ongoing operations coverage; someone injured years later by a defective stair railing installed by the contractor falls under completed operations coverage.

Typical Limits

CGL policies have two types of limits: per-occurrence (the maximum paid on any single claim) and aggregate (the maximum paid across all claims during the policy period). Typical limits for commercial construction contractors:

Most construction projects require specific minimum limits that the sub must meet. Meeting or exceeding the required limits is a basic qualification step — subs without adequate limits can't perform the work. The umbrella/excess policy is how most mid-size contractors meet higher-limit requirements without dramatically increasing the base CGL premium.

Critical Exclusions

CGL policies exclude specific categories of loss that are either uninsurable, covered by other policies, or outside the policy's scope. Understanding the exclusions is as important as understanding the coverage.

The Additional Insured Endorsement

One of the most important CGL features for construction contracts is the additional insured endorsement. When a GC contracts with a sub, the sub's CGL typically names the GC as an additional insured on the sub's policy. This means the sub's coverage protects the GC too — if a claim arises from the sub's work, the sub's insurance responds even when the GC is named as a defendant.

The additional insured endorsement is the coverage that actually shifts risk from GC to sub. The certificate of insurance alone doesn't provide coverage — the underlying endorsement does. The standard ISO endorsements are CG 20 10 (for ongoing operations) and CG 20 37 (for completed operations). Both should typically be required on subs' CGL.

Primary and Non-Contributory Language

Standard CGL coverage responds on a pro-rata basis when multiple policies cover the same loss. For construction, this default is often modified by requiring the sub's CGL to be 'primary and non-contributory' with respect to the GC's CGL. This means the sub's policy pays first and in full; the GC's policy doesn't contribute.

Without primary and non-contributory language, a claim on a sub's work could end up being paid partly by the sub's CGL and partly by the GC's CGL — even though the incident was the sub's responsibility. The primary and non-contributory wording eliminates that cost-shifting and ensures the sub's insurance bears the loss as intended.

Ongoing Operations vs. Completed Operations

CGL distinguishes between ongoing operations (work still in progress) and completed operations (work that's been finished and turned over). Both are covered, but the completed operations coverage is particularly important for construction because claims often arise years after the work is completed.

The additional insured endorsement needs to cover both phases. CG 20 10 (or its equivalent) covers ongoing operations; CG 20 37 covers completed operations. A GC or owner named additional insured only for ongoing operations loses the protection once the project is complete — which is exactly when completed operations claims start to surface.

Policy Period vs. Claim Timing

CGL policies are 'occurrence' policies — they cover incidents that occur during the policy period, regardless of when the claim is made. A roof installed in 2024 that fails in 2030 is covered under the 2024 policy if the claim can be tied to the work performed then.

This is different from 'claims-made' policies (common in professional liability), which cover claims made during the policy period regardless of when the underlying incident occurred. For construction CGL, the occurrence structure is standard and is why maintaining continuous CGL coverage year after year matters — a gap in coverage creates a gap in protection for work performed during the gap period.

Common CGL Issues in Construction

Bottom Line

Commercial general liability insurance is the most important single insurance line for construction contractors. It covers third-party bodily injury and property damage during construction and afterward, and the additional insured endorsements under CGL are how contractual risk-shifting between GCs and subs actually works in practice. Understanding what CGL covers, what it excludes, and how the endorsements function is basic literacy for anyone involved in construction insurance — and getting it right is what keeps the company protected when an incident eventually happens.