A certificate of insurance (COI) is a one-page document issued by an insurance carrier that confirms the policyholder holds active coverage. For construction, it typically shows general liability insurance, workers’ compensation insurance, and sometimes equipment or vehicle coverage. The COI includes policy numbers, coverage limits, policy dates, and the name of the certificate holder (the general contractor, owner, or lender as additional insured).
COIs are required before a subcontractor or vendor can legally start work on most residential projects. General contractors require them from all subs, lenders require them from the GC, marketplace platforms require them before approving a contractor. The COI protects all parties by documenting that the contractor carries insurance and is liable for injuries or property damage.
The certificate is typically valid for the policy period and becomes invalid when the policy renews (even with continuous coverage, a new certificate is needed). On long projects, requesting COI renewals 30 days before policy expiration prevents gaps. A COI is not proof of payment to insurance and does not mean coverage is comprehensive, but it is the standard due diligence requirement in residential construction.