"Commercial building" means any building other than: (i) a single-family home or a dwelling containing 2 or fewer apartments, condominiums, or townhouses; or (ii) a farm building as exempted from Section 3 of the Illinois Architecture Practice Act of 1989.
"Newly constructed commercial building" means any commercial building for which original construction has commenced on or after July 1, 2011.
"Non-building code jurisdiction" means any area of the State in a municipality or county having jurisdiction that: (i) has not adopted a building code; or (ii) is required to but has not identified its adopted building code to the Board under Section 10.18 of the Capital Development Board Act .
"Qualified inspector" means an individual certified as a commercial building inspector by the International Code Council or an equivalent nationally recognized building inspector certification organization, qualified as a construction and building inspector by successful completion of an apprentice program certified by the United States Department of Labor , or who has filed verification of inspection experience according to rules adopted by the Board for the purposes of conducting inspections in non-building code jurisdictions.
"Substantial damage" means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed 50% of the market value of the structure before damage occurred.
"Substantially improved commercial building" means, for work commenced on or after January 1, 2025, any commercial building that has undergone any repair, reconstruction, rehabilitation, alteration, addition, or other improvement, the cost of which equals or exceeds 50% of the market value of the structure before the improvement or repair is started. If a commercial building has sustained substantial damage, any repairs are considered substantial improvement regardless of the actual repair work performed. "Substantially improved commercial building" does not include: (i) any project for improvement of a structure to correct existing violations of State or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions or (ii) any alteration of a historic structure, provided that the alteration will not preclude the structure's continued designation as a historic structure.
20 ILCS 3105/10.09-1