Composite Deck costs $38.32 to $81.43 per sq ft in Idaho in 2026. For a 400 sq ft project, that puts the installed total at $15,328 – $32,572, with most projects landing near $23,950. Idaho is about 4% below the national average.
Why Idaho prices differ from the national average
Roughly 42% of the installed cost of composite deck is labor, and labor is the part of the bill that actually moves between states. Idaho construction wages average $33.27 per hour against a national figure near $36.97 — a wage index of 0.90×.
Materials behave differently. Framing lumber, decking boards, fasteners, and railing are priced on national commodity and manufacturer markets, so material costs barely move from one state to the next. That is why we apply the wage index only to the labor share and hold materials at national prices. Doing that puts Idaho at $38.32 to $81.43 per sq ft, against a national baseline of $40.00 to $85.00.
Two other forces sit on top of that. Metro areas inside Idaho price above the statewide figure because of wages, permitting, and site access. And the state’s deep frost line adds excavation and below-grade volume that southern states never pay for.
Composite Deck cost by project size in Idaho
These figures apply the Idaho rate to common project sizes. They cover a standard specification with normal site access.
| Project size | Idaho cost range | Typical |
|---|---|---|
| 10×10 (100 sq ft) | $3,832 – $8,143 | $5,988 |
| 12×12 (144 sq ft) | $5,518 – $11,726 | $8,622 |
| 12×16 (192 sq ft) | $7,357 – $15,635 | $11,496 |
| 12×20 (240 sq ft) | $9,197 – $19,543 | $14,370 |
| 16×20 (320 sq ft) | $12,262 – $26,058 | $19,160 |
| 20×20 (400 sq ft) | $15,328 – $32,572 | $23,950 |
Where the money actually goes
For a 400 sq ft project in Idaho at roughly $23,950, a typical bill splits like this:
| Line item | Share | Cost |
|---|---|---|
| Labor | 42% | $10,059 |
| Materials | 44% | $10,418 |
| Site prep & equipment | 9% | $2,084 |
| Overhead, disposal & finishing | 6% | $1,389 |
The labor share is why identical projects diverge so sharply between states. It is also why a bid that comes in far below these numbers usually means a thinner specification or a crew cutting site prep, not a genuine bargain.
Composite Deck cost by city in Idaho
Statewide averages hide a lot. Boise, Idaho Falls, Coeur d’Alene all price above the Idaho average, while rural counties run below it:
| Area | Cost per sq ft | A 400 sq ft project | vs state |
|---|---|---|---|
| Boise | $42.15 – $89.57 | $26,345 | +10% |
| Idaho Falls | $39.09 – $83.06 | $24,429 | +2% |
| Coeur d’Alene | $40.62 – $86.32 | $25,387 | +6% |
| Rural Idaho | $35.64 – $75.73 | $22,274 | −7% |
What is included in a Idaho quote — and what is not
A complete quote for this work should list dimensions, specification and grade, site preparation, materials, labor, cleanup, and disposal. Those are the items already reflected in the ranges above.
Costs that usually sit outside the headline number: permits (around $400 in Idaho), demolition or removal of existing work, unusual site access, drainage or grading corrections, and any upgrade to the standard specification. When two bids differ by thousands, the gap is nearly always one of these, not the labor rate.
Frost depth and code requirements in Idaho
Permits in Idaho
A residential permit for work of this type and value in Idaho typically runs around $400, though the figure varies by municipality and often scales with declared project value. Permit cost is rarely folded into a contractor’s per-sq ft quote, so add it separately when comparing bids. Confirm requirements with your local building department before work begins — unpermitted work can surface later during a sale or insurance claim.
Best time of year to schedule in Idaho
Idaho has a solid working season from spring through late autumn, with a genuine winter slowdown. Demand peaks in late spring and early summer, which is also when quotes are highest. Scheduling in early spring or after the autumn rush often saves money.
DIY versus hiring a contractor in Idaho
Materials account for roughly 58% of the installed price, so a 400 sq ft project carries about $13,891 in materials against an installed cost near $23,950. The gap is labor, equipment, and the risk of getting it wrong.
Because Idaho labor runs at 0.90× the national rate, the DIY saving here is closer to the national norm. Weigh it against tool rental, waste disposal, permit responsibility, and the fact that remedial work almost always costs more than doing it right the first time.
How Idaho compares with nearby states
Idaho sits in the West region. Here is how neighbouring states price the same specification:
| State | Cost per sq ft | vs Idaho |
|---|---|---|
| New Mexico | $38.32 – $81.43 | Same as Idaho |
| Montana | $38.49 – $81.79 | Higher than Idaho |
| Wyoming | $39.50 – $83.93 | Higher than Idaho |
| Utah | $39.66 – $84.29 | Higher than Idaho |
| Arizona | $39.83 – $84.64 | Higher than Idaho |
| Nevada | $40.84 – $86.79 | Higher than Idaho |
Getting an accurate number for your project
Everything above is a planning range. Enter your real dimensions and specification to get a figure with Idaho rates already applied:
Open the composite deck calculator →Then get three written, itemised quotes. Make sure each one specifies the same dimensions and the same grade of material — that is the only way a comparison means anything.
Frequently asked questions
How much does composite deck cost in Idaho?
In 2026, composite deck costs $38.32 to $81.43 per sq ft in Idaho. For a 400 sq ft project, the installed total typically lands between $15,328 and $32,572, with most projects near $23,950.
Is composite deck more expensive in Idaho than the national average?
Idaho is about 4% below the national average. The driver is a construction wage index of 0.90 times the national figure, applied to the roughly 42% of the project cost that is labor.
Which parts of Idaho are most expensive?
Boise, Idaho Falls, and Coeur d’Alene price above the statewide average because of higher wages, stricter permitting, and tighter site access. Rural counties typically run around 7% below the state figure.
Do I need a permit in Idaho?
Most municipalities in Idaho require a permit for work of this type and value. Budget around $400 and confirm with your local building department before work starts, since requirements vary between cities and counties.
How deep is the frost line in Idaho?
The frost line in Idaho is roughly 36 inches. Footings and posts must extend below that depth to avoid frost heave, which adds excavation and material to the job.
When is the cheapest time to book this work in Idaho?
Idaho has a solid working season from spring through late autumn, with a genuine winter slowdown. Demand peaks in late spring and early summer, which is also when quotes are highest. Scheduling in early spring or after the autumn rush often saves money.
How much of the cost is labor versus materials?
Labor is about 42% of the installed price and materials about 58%. That split is why state wage differences move the total so much, and why material price swings move it less than people expect.
Why do contractor quotes in Idaho vary so much?
Three things move a quote most: metro versus rural location, site access and preparation, and the specification itself. Two bids are only comparable when both list the same dimensions, the same grade of material, and the same scope of prep work.