Estimates are for planning purposes only and based on 2025 contractor data.
Always get at least 3 quotes before hiring. Prices vary by ZIP code, site conditions, and contractor availability.
Deck costs in Illinois vary significantly by region in 2026. Chicago and its suburbs run 15 to 25 percent above the national average while downstate Illinois is closer to or below average. Expect to pay $20 to $38 per square foot for pressure-treated wood and $38 to $70 per square foot for composite decking.
Frequently Asked Questions
How much does a deck cost in Illinois in 2026?
Illinois homeowners typically pay between $5,500 and $14,500 for a new deck in 2026. Chicago metro decks run significantly higher than downstate builds due to higher labor costs and stricter permitting requirements.
What is the best decking material for Illinois?
Composite decking is highly recommended for Illinois due to harsh winters, freeze-thaw cycles, and summer humidity. Pressure-treated wood is also commonly used but requires more maintenance to handle Illinois weather extremes.
Do I need a permit to build a deck in Illinois?
Yes, Illinois requires building permits for most deck projects. Chicago has particularly detailed requirements including structural plans and multiple inspections. Permit costs range from $150 to $800 depending on your municipality.
When is the best time to build a deck in Illinois?
May through October is the best building window in Illinois. Spring and early fall offer the most favorable conditions. Winter builds are generally not recommended due to frozen ground and extreme temperatures.