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§ 02
When a permit is required
Permit triggers and exempt work for Cook County
A building permit is required before beginning any construction, addition, alteration, repair, demolition, or change of occupancy under the Illinois Building Code (2025, IBC-based). Local jurisdictions enforce state code; contact your municipal or county building department for specific thresholds and exemptions.
§ 03
Frequently asked
Common questions about unincorporated Cook County permits
01 Do I need a building permit in unincorporated Cook County, IL? ▸
A building permit is required before beginning any construction, addition, alteration, repair, demolition, or change of occupancy under the Illinois Building Code (2025, IBC-based). Local jurisdictions enforce state code; contact your municipal or county building department for specific thresholds and exemptions.
last verified April 2026
entry id permits/illinois/cook/unincorporated
Educational reference. Permit rules and fees change — confirm current requirements directly with Department of Building and Zoning (BNZ) before applying. Jaspector is not legal advice.