Deck Building Cost in Illinois
2026 estimates — composite, pressure-treated, and hardwood
300 sqft composite deck, single level, Illinois labor rates. Updated June 2026.
Calculate Your Illinois Deck Cost
Deck Cost by Material — Illinois 2026 (300 sqft)
| Material | 300 sqft (IL) | Per sqft |
|---|---|---|
| Pressure-treated lumber | $6,900 | $23/sqft |
| Cedar | $9,315 | $31/sqft |
| Composite (Trex, TimberTech) | $12,075 | $40/sqft |
| Tropical hardwood (Ipe) | $16,560 | $55/sqft |
Installed including framing, hardware, and labor. Illinois rates applied. Railing not included above.
Building a Deck in Illinois — What to Know
1. Illinois Costs vs. National Average
Deck building in Illinois is above the national average (cost index: 1.15×). A 300 sqft composite deck averages $12,075 — composite costs 75% more than pressure-treated but requires virtually no maintenance.
2. Best Deck Material for Illinois
Illinois decks see 5–6 months of use (May–October). Chicago area requires permits and detailed deck plans — budget $400–$1,000 for permits in Cook County municipalities. Chicago's harsh freeze-thaw cycles make composite decking strongly recommended. North Shore Chicago suburbs (Winnetka, Lake Forest) and western suburbs (Naperville, Hinsdale) have premium deck markets where composite and Ipe hardwood are standard.
3. Permits & Requirements in Illinois
Most decks over 30 inches above grade require a building permit in Illinois. Permit costs average $200–$600. Attached decks require structural assessment of the ledger board connection to your home. Always pull permits — unpermitted decks must be disclosed at sale and can require removal.
FAQs — Deck Cost in Illinois
Deck building in Illinois costs $9,775 on average for a 300 sqft deck — above national average in Chicago metro. Composite decking is essential in Chicago's harsh winters. Pressure-treated lumber: $6,900 for 300 sqft; composite: $12,075. Downstate IL runs 15–20% below Chicago metro.
In Illinois, composite decking (Trex, TimberTech) costs $12,075 vs $6,900 for pressure-treated wood for 300 sqft. Composite has a 25–50 year warranty and requires no annual staining ($300–$600/year for wood). Most Illinois homeowners choose composite for its long-term value.
Most Illinois municipalities require permits for decks over 30 inches above grade, attached decks regardless of height, and decks over 200 sqft. Permit costs range $200–$800. Always pull permits — unpermitted construction must be disclosed at home sale and can result in forced removal.
Deck railing adds $1,500–$4,500 for a typical 60 linear foot deck in Illinois. Pressure-treated railing runs $1,725 installed; composite railing $2,760; cable railing $4,140. Aluminum and composite railings require zero maintenance and are often the best long-term value.
Deck lifespan varies by material: pressure-treated lumber lasts 15–20 years with annual staining ($300–$600/year); cedar lasts 20–30 years; composite (Trex, TimberTech) lasts 25–50 years with minimal upkeep; tropical hardwood (Ipe) lasts 40–75 years. Illinois's climate and precipitation levels affect how quickly wood degrades — composite is a better investment in states with significant rain or temperature swings.
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Get Free Quotes on AngiIllinois Deck Summary
- →Composite avg: $12,075 / 300 sqft
- →PT lumber: $6,900 / 300 sqft
- →Range: $7,331 – $13,685
- →Cost index: above national avg