Illinois housing stock · construction eras

What's Inside an Old Illinois House, by Era

The year a house was built tells you what is behind the plaster long before anyone opens it: which wiring, which pipe, which insulation, and which material now needs a licensed contractor to remove.

Era shares: U.S. Census Bureau, American Community Survey table B25034, five-year estimates.

Independent — not a government agency, an inspector, or a remediation contractor.