Key findings
- Location swings cost ~39%. The same 16×20 composite deck runs $14,720–$23,552 in the South but $20,480–$32,768 on the West Coast — purely on labor.
- National average: a 16×20 mid-composite deck is $16,000–$25,600 installed in 2026.
- Material matters more than size: the same 320 sqft is $8,000–$12,800 in pressure-treated wood vs $24,000–$35,200 in premium composite/PVC.
- Frost depth is the hidden cost. It ranges from 0″ (Arizona, Florida) to 60″ (Alaska); in the deepest-frost states, footings alone can be 30–40% of the budget.
Cost by region
Labor is the variable that moves with geography (materials ship at near-national prices). For the reference 16×20 mid-composite deck:
Most and least expensive states
Ranked by regional labor index, with frost depth as the tie-breaker (it drives footing cost). Dollar ranges are the reference 16×20 composite deck.
Labor indices are regional (RSMeans 2026-Q1 residential deck installation); states within a region share a labor index, so frost depth and local permit fees break the ties shown above.
The frost-depth factor
Footings must extend below the frost line (IRC R403.1.4) so the deck doesn't heave in winter. The deeper the frost, the more concrete, excavation, and labor each footing needs — a cost that never shows up in a per-square-foot quote. The deepest-frost states:
Cost by material
Holding the reference 16×20 (320 sqft) constant at the national-average labor index:
Want your exact number? Run the deck cost calculator with your size, material, and state, or browse cost by size and cost by state.
Methodology & sources
All figures are installed cost (decking material + labor) for a simple rectangular build, 2026-Q1. Regional labor indices follow RSMeans residential deck installation data (South 0.92×, Midwest 1.00×, Northeast 1.22×, West 1.28×). Frost depths follow state building-code minimums per IRC R403.1.4; local AHJs sometimes require deeper. Material price bands are national-average retail. The reference build is a 16×20 (320 sqft) deck — the most-searched mid-large size. These are planning estimates; a complete project (framing, footings, railing, stairs, permit, contingency) is itemized by the calculator, and our full method is on the methodology and sources pages.
Free to cite with attribution to DeckMath (deckmath.com/deck-cost-report). Published June 25, 2026.
Deck cost report — FAQ
What is the average cost to build a deck in 2026?
A 16×20 (320 sqft) mid-range composite deck averages $16,000–$25,600 installed at the US national average. The same deck in pressure-treated wood runs $8,000–$12,800, and in premium composite or PVC $24,000–$35,200. Cost scales near-linearly with square footage.
Which states are the most expensive to build a deck?
West Coast states (California, Washington, Oregon, plus Alaska, Arizona, Colorado, Nevada) carry the highest labor index at 1.28× the national average, followed by the Northeast at 1.22×. Alaska is the single most expensive once frost depth (up to 60″) is added — footings alone can be 30–40% of the budget. The same 16×20 composite deck costs about 39% more in the West ($20,480–$32,768) than in the South ($14,720–$23,552).
Which states are the cheapest to build a deck?
Southern states — Alabama, Arkansas, Texas, Mississippi, Louisiana, Tennessee, Georgia, Florida — have the lowest labor index at 0.92× the national average and shallow frost depths (0–12″), which keeps footing costs low. A 16×20 composite deck in the South runs about $14,720–$23,552 installed.
Why does deck cost vary so much by state?
Two factors. (1) Labor: regional installation rates range from 0.92× (South) to 1.28× (West Coast) — a ~39% swing on the same build. (2) Frost depth: footings must extend below the frost line (IRC R403.1.4), which ranges from 0″ in Arizona and Florida to 60″ in Alaska. Deep-frost states pay far more in concrete and excavation. Materials themselves are near-national-average because decking ships from regional distribution centers.