Deck Cost in New Hampshire (2026)

In New Hampshire, expect $30-60/sqft installed for pressure-treated, $50-90 for mid-range composite, and $90-140 for premium composite or tropical hardwood. Labor in New Hampshire runs 1.22× the national average (Northeast region, RSMeans 2026-Q1 residential indices), so a typical 16×20 (320 sqft) deck lands around $21,472-$29,280 for mid-tier composite. Materials themselves stay close to national average because decking ships from regional distribution centers, which means nearly all of the New Hampshire premium or discount sits on the labor line — HomeAdvisor / Angi 2026 pricing shows the same spread. Budget separately for the permit (regional baseline ~$320) and for footings: New Hampshire's ~48″ frost depth (IRC R403.1.4) can move foundation cost by four figures on a deep-frost site. Treat these ranges as a simple-rectangle baseline — complex shapes, tall framing, and hard access push totals higher — and always compare 2-3 local bids.

New Hampshire permit fees typically run $130-450 depending on jurisdiction and project value. Most calculators, including DeckMath, model the fee as max(regional baseline, 1.2% of project value) — the Northeast baseline is about $320, so a $15,000 project prices nearer $180 than the minimum. NH permits $200-340. Under IRC 2021 R105, a permit is generally required once a deck exceeds 200 sqft, sits more than 30″ above grade, or attaches to the house — which covers most real-world builds. The caveat: permitting is hyper-local. Two towns in the same county can differ on fee schedule, plan-review requirements, and inspection count, and unpermitted decks routinely surface at resale or on insurance claims. Confirm the exact fee and drawing requirements with your local building department before ordering materials.

New Hampshire's frost depth is approximately 48″. Footings must extend below the frost line per IRC R403.1.4 — verify with your local building department, since AHJs sometimes require deeper depths than the state-published value.

Most New Hampshire jurisdictions require a contractor's license for projects above a state-specific threshold ($1,000-25,000). DIY construction by a homeowner on their own property is typically allowed. Always confirm with your local building department before signing a contract.

In the DeckMath licensed-contractor registry (July 2026 snapshot), Manchester has 71 deck-capable licensed contractors within ~25 miles of downtown, Portsmouth has 62, Concord has 46. We geocode every license record and count within a 40 km (~25 mi) radius, so neighboring metros can overlap and service areas cross metro and state lines. Registry coverage varies by state (we ingest full state license registries where one exists), so treat these counts as a floor on the local market, not a census. A deeper pool of nearby licensed contractors generally means more competitive bids — compare 2-3 quotes either way.

Usually at the margin, yes. DeckMath prices New Hampshire at the state level — a 1.22× Northeast labor index (RSMeans 2026-Q1) — and does not publish per-metro multipliers, because no reliable metro-level residential deck labor survey exists. In practice, bids in major metros like Manchester and Concord tend to land in the upper half of the statewide range: for a 16×20 mid-composite build, expect quotes nearer $25,376-$29,280 than the statewide $21,472-$29,280. Big-city jurisdictions also sit at the top of the permit-fee range, and tight access (small lots, no machine access) adds labor hours. In smaller towns, bids near the bottom of the range are more common. Always compare 2-3 local bids.