How Much Does a Deck Cost in Illinois? (2026 Guide)
A new deck in Northern Illinois typically runs $15 to $45 per square foot installed, which puts a common 300–400 sq ft deck somewhere between $6,000 and $18,000. Material is the single biggest lever — here's the honest breakdown so you can budget before you call a builder.
Cost by material (installed, per square foot)
| Material | Per sq ft installed | Lifespan & upkeep |
|---|---|---|
| Pressure-treated pine | $15–$22 | ~15 yr; annual stain |
| Cedar | $22–$30 | 15–25 yr; stain every 2–3 yr |
| Composite (Trex/TimberTech) | $30–$45 | 30–40 yr; near-zero upkeep |
| Premium PVC / Ipê hardwood | $45–$75 | Top tier; low upkeep |
What else moves the number
- Size & height. Bigger and taller (more posts/footings, stairs) costs more per square foot.
- Railing. Wood is cheapest; aluminum, cable, and glass step up fast.
- Add-ons. Stairs, built-in benches, pergolas, lighting, and a fire-pit area each add cost — and character.
- Site conditions. Sloped yards, drainage, and footing depth (Illinois frost line) affect labor.
30-year cost, not just upfront
Cedar is cheaper to build but you'll stain it for years; composite costs more upfront but is close to zero maintenance for decades. Over 30 years the totals are closer than the sticker price suggests. If you'll stay in the home long-term, composite usually wins on total cost and hassle.
Permits
Most Illinois municipalities require a permit for a deck, with rules on footings, railing height, and setbacks. Budget time for it and make sure your builder pulls it.
See it before you build
Before you commit to a material, color, and railing, see it on your actual backyard with the free Deck Visualizer — render composite vs cedar side by side, try railing options, and add a pergola or lighting to see how the project changes.
Frequently asked questions
How much does a deck cost in Illinois in 2026?
About $15–$45 per square foot installed depending on material, so a typical 300–400 sq ft deck runs roughly $6,000–$18,000.
Is composite or cedar cheaper?
Cedar is cheaper to build ($22–$30/sq ft) but needs staining every 2–3 years. Composite costs more ($30–$45/sq ft) with near-zero upkeep, so over 30 years the totals are close.
Do I need a permit for a deck in Illinois?
Most municipalities require one, with rules on footings, railing height, and setbacks. Confirm with your village and have your builder pull the permit.
Can I see a deck on my yard before building?
Yes — the free Deck Visualizer renders material, color, railing, and add-ons onto a photo of your backyard.