Cost to Build a Deck in Illinois (2026)
A 12×16 ft deck in Illinois runs about $4,949 in pressure-treated pine and $10,236 in composite, installed — 11% above the US average. Here is what moves that number in Illinois, with a calculator priced for the state.
Pressure-treated pine
$22–$29 /sq ft
Cedar
$31–$41 /sq ft
Composite
$46–$60 /sq ft
Deck cost calculator for Illinois
Priced with Illinois labour, material and footing-depth factors. Change any input and the estimate updates.
Estimated installed cost
$9,007 – $11,771
192 sq ft · about $53.31/sq ft
- Materials
- $6,257
- Labour
- $3,979
- Footings (39 in deep)
- 3 × about $215
- Frost-depth adjustment
- +$144
Mid-range estimate for a rectangular deck attached to the house, with one beam line per 12 ft of depth and footings every 8 ft. Excludes demolition, permits and site work. For railing, stairs and a full line-item breakdown use the main deck cost calculator.
Illinois deck cost by size and material
Mid-range installed prices for a standard-height deck attached to the house, including framing, footings at the local depth and hardware. Railing and stairs are priced separately in the main deck cost calculator.
| Deck size | Pressure-treated pine | Cedar | Composite |
|---|---|---|---|
| 10 × 10 ft (100 sq ft) | $2,647 | $3,704 | $5,400 |
| 12 × 12 ft (144 sq ft) | $3,748 | $5,270 | $7,713 |
| 12 × 16 ft (192 sq ft) | $4,949 | $6,979 | $10,236 |
| 16 × 20 ft (320 sq ft) | $8,392 | $11,776 | $17,203 |
| 20 × 20 ft (400 sq ft) | $10,394 | $14,624 | $21,408 |
What drives deck prices in Illinois
Labour
Labour is the biggest regional variable. Carpentry labour in Illinois runs 25% above the national level, so a composite 12×16 that averages $9,216 nationally comes to about $10,236 here. On pressure-treated decks labour is more than half the bill, so the regional gap is widest on the cheapest material.
Climate
Cold, snowy winters with deep freeze-thaw cycling and hot, humid summers.
Footings and frost depth
Footings in Illinois typically go 36–42 inches deep. At 39 inches each 12 inch footing costs roughly $215 installed, and a 12×16 deck needs about 3 of them — a premium of $144 against the 24 inch depth national prices assume.
Which decking makes sense here
Our pick for most Illinois homes: composite. Union-scale labour in the Chicago area makes repeated wood maintenance costly. Composite adds about $5,287 to a 12×16 deck over pressure-treated — see the full 20-year comparison in the composite vs wood calculator.
Permits and code in Illinois
There is no single statewide residential code; municipalities adopt their own, usually the IRC. Chicago has its own building code and strict porch and deck rules, and frost depth is commonly 42 inches in the north.
Typical deck permit fees: $100–$600. Expect a footing inspection before concrete, a framing inspection before the decking goes down and a final. Estimate your fee with the deck permit cost calculator, and read our deck permit guide for what the drawings need to show.
Best time to build a deck in Illinois
May to October.
Deck cost in Illinois cities
- Chicago — 12×16 composite about $10,615
Compare neighbouring states
Frequently asked questions
How much does it cost to build a deck in Illinois?
A typical 12×16 ft (192 sq ft) deck in Illinois costs about $4,949 installed in pressure-treated pine, $6,979 in cedar and $10,236 in composite. That is $22–$29 per square foot for pressure-treated and $46–$60 for composite — 11% above the US average.
Is a composite deck worth it in Illinois?
On a 12×16 deck composite costs about $5,287 more than pressure-treated up front. Union-scale labour in the Chicago area makes repeated wood maintenance costly. Composite needs no staining, which saves a refinishing cycle every two to three years on wood.
Do I need a permit to build a deck in Illinois?
There is no single statewide residential code; municipalities adopt their own, usually the IRC. Chicago has its own building code and strict porch and deck rules, and frost depth is commonly 42 inches in the north. Where a permit is required, fees typically run $100–$600. Under the model residential code, a freestanding deck under 200 sq ft and no more than 30 inches above grade that does not serve an exit door is often exempt — attaching it to the house removes that exemption.
How deep do deck footings need to be in Illinois?
Typically 36 to 42 inches depending on the part of the state. At about 39 inches, each 12 inch footing costs roughly $215 installed, compared with $167 at a 24 inch depth. Confirm the exact depth with your building department before digging.
When is the best time to build a deck in Illinois?
May to October. Booking a builder outside the spring rush often gets a faster start date and a keener price.
Is Illinois expensive for deck building compared with other states?
Illinois ranks 44 of 50 from cheapest to most expensive on our index. Carpentry labour runs 25% above the national level and materials right in line with it, which puts a typical deck 11% above the US average.
Price the rest of the project
How these figures are made: national installed prices per square foot, split into materials and labour and adjusted by a Illinois labour index (reasoned from BLS state carpenter wage data), a material and freight index, and the local footing depth. They are planning estimates — get two or three itemised local quotes. Method.