Composite deck cost in Janesville, WI
Local estimate from BLS wage data and BEA price levels. Reviewed Nov 4, 2026.
- Typical range (300 sq ft)
- $13,400 – $26,900
- Per sq ft
- $44.50 – $89
- before permit
- Versus US midpoint
- +11%
- US $18,100
- Rank of 300 metros
- #38
- 1 = most expensive
Janesville homeowners pay roughly $13,400 to $26,900 to build a composite deck at 300 sq ft, or $44.50 to $89 per sq ft (permit not included). Against the US midpoint, Janesville is 11% higher. Carpenters earn a median of $36.24 an hour in the Janesville area, 24% above the US median of $29.12.
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Estimated cost for 300 sq ft in Janesville, WI, standard level
$17,500 to $22,800
About $58 to $76 per sq ft before permits. Labor is about 66% of the bill.
| Part | Low | High |
|---|---|---|
| Materials | $5,850 | $7,650 |
| Labor | $11,500 | $15,100 |
| Permits and fees | $75 | $110 |
| Total | $17,500 | $22,800 |
Cost breakdown for 300 sq ft in Janesville, WI
| Part of the job | Low | Midpoint | High | Share |
|---|---|---|---|---|
| Materials | $4,500 | $6,750 | $9,000 | 34% |
| Labor | $8,850 | $13,300 | $17,700 | 66% |
| Permits and fees | $45 | $95 | $140 | 0% |
| Total | $13,400 | $20,200 | $26,900 | 100% |
What is behind the Janesville number
Labor is 66% of the midpoint bill here, against 60% nationally. The mix of trades behind this job is carpenters (80%), construction laborers (20%). We weight each trade's local median wage by that share and compare it with the national median. In Janesville the blended ratio comes out at 1.23.
On the materials line, the BEA goods price index for the Janesville metro is 93.8 (US = 100). The midpoint materials bill for 300 sq ft comes to $6,750, compared with $7,200 at national prices. Permit and inspection fees are scaled by the broader index (93.7) and land at $45 to $140.
Optional extras in Janesville
Extras are quoted nationally and then scaled to Janesville by the average of the local wage index (1.23) and goods index (0.94), a factor of 1.08. Tick any of them in the estimator above to add them to your total. Treat these as planning figures: an add-on touches different trades than the main job, so the scaling is an approximation.
| Add-on | Local range |
|---|---|
| Add a deck railing (approx. 0.3 ft per sq ft) | $1,950 – $5,850 |
Janesville against nearby metros and the rest of Wisconsin
Contractors rarely work more than an hour or two from home, so the neighboring metros set a rough ceiling and floor for your quotes. Midpoints for 300 sq ft range from $18,000 to $20,200 across Janesville and its five closest metros.
| Area | Range | Midpoint | vs. here |
|---|---|---|---|
| Janesville, WIthis page | $13,400 – $26,900 | $20,200 | |
| Rockford, IL25 miles | $13,200 – $26,500 | $19,900 | −1% |
| Madison, WI40 miles | $12,300 – $24,700 | $18,500 | −8% |
| Kenosha, WI60 miles | $12,400 – $24,800 | $18,600 | −8% |
| Milwaukee, WI65 miles | $12,400 – $24,800 | $18,600 | −8% |
| Racine, WI65 miles | $12,000 – $24,100 | $18,000 | −11% |
| Wisconsin (statewide) | $12,200 – $24,400 | $18,300 | −9% |
| United States | $12,100 – $24,200 | $18,100 | −10% |
Across 300 US metros, Janesville comes in at #38 from the top. The priciest is Honolulu, HI at $25,200; the cheapest is Brownsville, TX at $13,500 (midpoints, 300 sq ft). Statewide, Janesville is 10% above the Wisconsin figure.
Other Wisconsin metros
| Metro | Size | Range | Midpoint | vs. here |
|---|---|---|---|---|
| Milwaukee, WI | 820,780 jobs | $12,400 – $24,800 | $18,600 | −8% |
| Madison, WI | 408,070 jobs | $12,300 – $24,700 | $18,500 | −8% |
| Green Bay, WI | 174,550 jobs | $12,000 – $24,000 | $18,000 | −11% |
| Appleton, WI | 124,230 jobs | $12,300 – $24,600 | $18,500 | −8% |
| Oshkosh, WI | 93,750 jobs | $14,100 – $28,300 | $21,200 | +5% |
| Eau Claire, WI | 86,060 jobs | $11,900 – $23,900 | $17,900 | −11% |
Cities with a workforce like Janesville's
Big cities and small ones price differently, so here is Janesville against the 4 metros with the closest total employment.
| Metro | Size | Range | Midpoint | vs. here |
|---|---|---|---|---|
| Lexington Park, MD | 70,650 jobs | $12,200 – $24,500 | $18,300 | −9% |
| Wausau, WI | 69,530 jobs | $10,900 – $21,900 | $16,400 | −19% |
| Bismarck, ND | 71,270 jobs | $11,400 – $22,800 | $17,100 | −15% |
| Yuma, AZ | 68,880 jobs | $10,500 – $21,100 | $15,800 | −21% |
Related projects, priced for Janesville
Because every project leans on different trades, Janesville's wage level does not move all prices equally. Against the US midpoint, concrete patio runs +11% and gutters +2%.
| Project | Size | Range | vs. US |
|---|---|---|---|
| Wood deck | 300 sq ft | $8,050 – $16,100 | +7% |
| Concrete patio | 300 sq ft | $1,300 – $4,500 | +11% |
| Paver patio | 300 sq ft | $3,250 – $5,900 | +8% |
| Gutters | 160 linear ft | $1,350 – $4,250 | +2% |
Cost by quality level and size in Janesville
Three bands are cut from the same cited range and localized for Janesville wages and prices. They overlap on purpose: a good standard job and a modest premium job can cost the same. The grid below prices the same bands at 4 common sizes.
Basic
$13,400 to $18,800
Entry-level composite boards, low deck, simple shape
Standard
$17,500 to $22,800
Mid-grade capped boards with railing and stairs
Premium
$21,500 to $26,900
Premium capped or PVC boards, multi-level, hidden fasteners
| Size | Basic | Standard | Premium |
|---|---|---|---|
| 10x12 (120 sq ft) | $5,400 – $7,550 | $7,050 – $9,200 | $8,650 – $10,800 |
| 12x12 (144 sq ft) | $6,450 – $9,050 | $8,400 – $11,000 | $10,400 – $13,000 |
| 16x20 (320 sq ft) | $14,300 – $20,100 | $18,600 – $24,400 | $22,900 – $28,700 |
| 20x20 (400 sq ft) | $17,900 – $25,000 | $23,300 – $30,400 | $28,600 – $35,800 |
Why two Janesville quotes can differ
Drainage
Ground-level decks over poorly draining yards may need $1,000-$4,000 of drainage work first.
Engineering
Large or complex decks may need a structural engineer at $100-$220 an hour to get a permit.
Board grade
Composite materials run $16-$32 per sq ft and the installed price is $40-$80 per sq ft, including the substructure (HomeGuide).
Local wages behind the labor line
Wages are the part of this estimate that changes most from town to town. 2 trades carry the job here, and each is compared with its US median. The weighted result for Janesville is 1.23 times the national level.
For carpenters (47-2031, weighted 80%) the local median is $36.24 an hour, which is 24% above the national $29.12. The middle half of them earn between $23.92 and $39.98 an hour. BLS counts 360 of them working in the area, 51.5 for every 10,000 jobs (US: 43.1), so the local bench is deeper than average.
Construction laborers (47-2061), 20% of the weighting: a median of $26.77 an hour, 18% above the US median of $22.66. The middle half of them earn between $22.00 and $36.28 an hour. About 480 work in the metro. That is 68.7 per 10,000 jobs, compared with 70.5 nationally, so the supply of crews looks typical.
Quotes come from real crews, not medians. If the carpenters on your job are paid at the 75th percentile ($39.98 an hour) instead of the median, the labor line grows by about $1,100. At the 25th percentile ($23.92) it shrinks by about $3,650. The total moves by 5.5% or 18.1%, so wages alone rarely explain a quote that is far outside our range.
For context on the local economy, BLS counts 69,870 jobs in the Janesville-Beloit area. That makes it the 260th largest of the 300 metros we cover, with 0.04% of US employment.
| Trade | Weight | 25th pct | Median | 75th pct | US median | Ratio | Level used |
|---|---|---|---|---|---|---|---|
| Carpenters (47-2031) | 80% | $23.92 | $36.24 | $39.98 | $29.12 | 1.24 | metro |
| Construction laborers (47-2061) | 20% | $22.00 | $26.77 | $36.28 | $22.66 | 1.18 | metro |
| Blended | 100% | 1.23 | |||||
When to schedule composite deck in Janesville
We use NOAA's 1991-2020 climate normals for Afton - Janesville Wwtp (5 miles from the city center). These are 30-year monthly averages, not forecasts.
March through November is the stretch where exterior installation runs into the fewest weather problems in Janesville (9 of 12 months). January, February and December have an average daytime high under 45°F.
In January, February and December the average high stays below 45°F. Sealants, adhesives and some materials, such as vinyl, are harder to install well in the cold, and short daylight cuts the working day.
Janesville gets about 37 inches of precipitation in a normal year, including roughly 37 inches of snow. The wettest months are June, July and August (5.0 inches in June). Inside the workable window, March and November are the driest, at 2.1 and 2.3 inches. The station averages about 13 days a year at 90°F or above.
Does the season change the price? Probably, but we do not have a sourced seasonal price curve, so the estimator shows a year-round figure and does not adjust by month. When you collect quotes, ask whether scheduling in a slower month gets a better rate.
| Month | Avg high °F | Avg low °F | Precip (in) | For this job |
|---|---|---|---|---|
| Jan | 28 | 12 | 1.6 | Cold |
| Feb | 32 | 15 | 1.6 | Cold |
| Mar | 45 | 25 | 2.1 | Workable |
| Apr | 58 | 36 | 3.6 | Workable |
| May | 70 | 48 | 4.1 | Workable |
| Jun | 80 | 58 | 5.0 | Workable |
| Jul | 83 | 62 | 4.2 | Workable |
| Aug | 82 | 60 | 4.3 | Workable |
| Sep | 75 | 51 | 3.7 | Workable |
| Oct | 62 | 40 | 3.0 | Workable |
| Nov | 46 | 29 | 2.3 | Workable |
| Dec | 34 | 18 | 1.9 | Cold |
Get 3 local quotes
Tell us about the job and we will try to connect you with up to three local contractors for written quotes. It is free and you are under no obligation to hire. Your estimate of $17,500 to $22,800 for Janesville, WI is attached.
A detailed PDF report of this estimate, $9
Multi-page report for Janesville, WI: low, typical and high cost, a line-item breakdown of materials and labor by trade, permit notes, the best months to schedule, a quote comparison sheet, red flags, questions for contractors, checklists and every source. Save your estimate above, preview page 1 free, and unlock the full report for $9 one-time, or get every report with CostLocal Pro.
Composite deck in Janesville: your questions
+How much does it cost to build a composite deck in Janesville?
For 300 sq ft, expect $13,400 to $26,900 in the Janesville area. A standard-spec job lands at $17,500 to $22,800. Small jobs usually cost more per sq ft and large ones less.
+What is the price per sq ft for composite deck in Janesville?
About $44.50 to $89 per sq ft for materials and labor, plus $45 to $140 for the permit if one is needed. The US range is $40 to $80.
+Is composite deck cheaper in Janesville or Rockford?
Rockford is 25 miles away. The midpoint for 300 sq ft there is $19,900, which is 1% less than Janesville ($20,200). Wage and materials indexes both feed that gap.
+How much of the bill is labor in Janesville?
About 66% at the midpoint, or $13,300 out of $20,200. Materials are 34% and permits 0%. Nationally, labor is 60%.
+What would 16x20 (320 sq ft) cost in Janesville?
$14,300 to $28,700. Pick a different size in the estimator above to get your own number.
+Does composite deck need a permit in Janesville?
Often, but rules are set by your city or county building office, so call before you hire. Budget $45 to $140 for fees in the Janesville area (our national range of $50 to $150 scaled by the local price level).
+Is Janesville expensive for composite deck compared with the rest of Wisconsin?
Janesville is 10% above the Wisconsin statewide estimate ($18,300 at the midpoint). We cover 12 metros in Wisconsin; see the state page to compare them.
+What do carpenters earn in Janesville?
The BLS median is $36.24 an hour in the Janesville area, compared with $29.12 nationally. The 25th to 75th percentile range is $23.92 to $39.98.
+What do basic and premium composite deck work cost in Janesville?
For 300 sq ft, basic work runs $13,400 to $18,800 and premium work $21,500 to $26,900. Basic means: entry-level composite boards, low deck, simple shape. Premium means: premium capped or PVC boards, multi-level, hidden fasteners.
+When is the best time to build a composite deck in Janesville?
Based on NOAA 1991-2020 normals, the comfortable months for this kind of work are March through November. March and November are typically the driest of those months. Local contractors' schedules matter as much as the weather, so book early for the busy months.
+What does "add a deck railing" add in Janesville?
$1,950 to $5,850 for 300 sq ft, from a national range scaled by the local wage and goods indexes.
Composite deck near Janesville
Where these numbers come from
Base prices are national ranges from the sources below. We scale labor by local BLS wages, materials by BEA goods prices and permits by the BEA all-items price level. Full method on the methodology page.
- HomeGuide: How Much Does Composite Decking Cost? (2026) (accessed November 4, 2026)
- HomeGuide: 2026 Building Permit Costs | Fees & Cost Calculator (accessed November 4, 2026)
- BLS Occupational Employment and Wage Statistics, May 2025
- BEA Regional Price Parities, 2024
- NOAA NCEI U.S. Climate Normals, 1991-2020