12×10 Deck Cost in Montana
A 12×10 (120 sqft) deck in Montana costs $7,680-$12,240 in mid-tier composite with the state's 1.28× labor multiplier (West). A 10×12 deck (120 sqft) is the median small-deck size in the US — the most-permitted deck size for first-time builders. Montana labor 1.28× national. Frost depth among the deepest in the US — footing cost dominates.
5 finish tiers — 12×10 in Montana
National $/sqft × Montana's 1.28× labor multiplier × 120 sqft = total installed cost. Materials + labor + standard railing included.
Excludes permit ($218-$537 typical in Montana), demolition (if replacing), and exceptional framing for 60″ frost depth. MT permits $150-280. Frost depth 60″ in northern MT.
12×10 framing notes for Montana
Montana considerations
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FAQ — 12×10 deck in Montana
How much does a 12×10 deck cost in Montana?▾
In Montana, a 12×10 (120 sqft) deck costs $3,840-$6,120 in pressure-treated, $7,680-$12,240 in mid-range composite (Trex Transcend / Fiberon Sanctuary), and $11,520-$16,920 in luxury composite/PVC (TimberTech AZEK / Trex Signature). Numbers reflect Montana's 1.28× labor multiplier on 2026-Q1 retail.
What's the cheapest way to build a 12×10 deck in Montana?▾
Cheapest = ground-level pressure-treated pine with no railings (where exempt under 30″ height) — ~$3,072-$4,608 in Montana. Add stairs + railings + above-grade framing and the build goes to ~$4,301-$6,144. DIY saves 30-50% on labor but requires permit + inspection coordination yourself.
How long does it take to build a 12×10 deck in Montana?▾
Permit timeline in Montana: 2-6 weeks depending on jurisdiction. Construction time for a 12×10: pro crew = 3-5 days for framing + boards + railings + stairs. DIY = 2-3 weekends for experienced DIYer. Allow extra time for permit approval + inspections.
What framing do I need for a 12×10 deck in Montana?▾
IRC R507-compliant framing for a 12×10 deck typically uses 2×8 joists at 16″ OC for spans up to 12 ft, 2×10 joists for spans 12-16 ft. Montana's frost depth is 60″ — footings must extend below that per IRC R403.1.4. Deep frost requires more concrete per footing — budget extra for sonotubes + concrete. Verify with your local building department.
Is composite worth it for a 12×10 deck in Montana?▾
Over 25 years in Montana: PT pine = ~$4,608 install + ~$9,600 maintenance (stain every 2-3 yr) = $14,208 total. Mid composite = ~$8,909 install + $0 maintenance = $8,909 total. Composite wins by 59-81% over 25-yr lifecycle PLUS better resale value in Montana's market.