30×20 Deck Cost in New Hampshire
A 30×20 (600 sqft) deck in New Hampshire costs $36,600-$58,800 in mid-tier composite with the state's 1.22× labor multiplier (Northeast). A 20×30 deck (600 sqft) is among the largest typical residential decks — often multi-tier with a kitchen wing. New Hampshire labor 1.22× national. Frost depth 48″.
5 finish tiers — 30×20 in New Hampshire
National $/sqft × New Hampshire's 1.22× labor multiplier × 600 sqft = total installed cost. Materials + labor + standard railing included.
Excludes permit ($240-$592 typical in New Hampshire), demolition (if replacing), and exceptional framing for 48″ frost depth. NH permits $200-340.
30×20 framing notes for New Hampshire
New Hampshire considerations
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FAQ — 30×20 deck in New Hampshire
How much does a 30×20 deck cost in New Hampshire?▾
In New Hampshire, a 30×20 (600 sqft) deck costs $18,600-$29,400 in pressure-treated, $36,600-$58,800 in mid-range composite (Trex Transcend / Fiberon Sanctuary), and $55,200-$80,400 in luxury composite/PVC (TimberTech AZEK / Trex Signature). Numbers reflect New Hampshire's 1.22× labor multiplier on 2026-Q1 retail.
What's the cheapest way to build a 30×20 deck in New Hampshire?▾
Cheapest = ground-level pressure-treated pine with no railings (where exempt under 30″ height) — ~$14,640-$21,960 in New Hampshire. Add stairs + railings + above-grade framing and the build goes to ~$20,496-$29,280. DIY saves 30-50% on labor but requires permit + inspection coordination yourself.
How long does it take to build a 30×20 deck in New Hampshire?▾
Permit timeline in New Hampshire: 2-6 weeks depending on jurisdiction. Construction time for a 30×20: pro crew = 8-14 days for framing + boards + railings + stairs. DIY = 5-8 weekends for experienced DIYer. Allow extra time for permit approval + inspections.
What framing do I need for a 30×20 deck in New Hampshire?▾
IRC R507-compliant framing for a 30×20 deck typically uses 2×8 joists at 16″ OC for spans up to 12 ft, 2×10 joists for spans 12-16 ft. New Hampshire's frost depth is 48″ — 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 30×20 deck in New Hampshire?▾
Over 25 years in New Hampshire: PT pine = ~$21,960 install + ~$45,750 maintenance (stain every 2-3 yr) = $67,710 total. Mid composite = ~$42,456 install + $0 maintenance = $42,456 total. Composite wins by 59-81% over 25-yr lifecycle PLUS better resale value in New Hampshire's market.