Room Addition Cost Calculator for Illinois - Free 2026 Cost Estimates

Room Addition costs in Illinois typically range from $92 - $288 per sq ft as of 2026. Illinois construction costs are 15% higher than the national average, with a regional cost multiplier of 1.15x. Average skilled labor rates in Illinois run approximately $58/hour. Use our free room addition calculator for a detailed estimate based on your specific project dimensions and requirements.

Permit requirements for room addition work in Illinois vary by municipality and project scope. Most cities and counties in Illinois require building permits for structural work, electrical modifications, and projects exceeding certain cost thresholds. Contact your local Illinois building department for specific requirements. Our calculator provides material and labor estimates that can help with your permit application budget planning.

Key factors affecting room addition costs in Illinois include: local labor rates (averaging $58/hour for skilled trades), material availability and regional pricing, permit and inspection fees, site conditions specific to Illinois's climate and geography, and project complexity. Illinois construction costs are above average primarily due to the Chicago metropolitan area, which has strong union requirements and prevailing wage mandates on public projects. Getting multiple quotes from licensed Illinois contractors is recommended for the most accurate pricing.