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Deck building · $40–$80 per sq ft
Composite deck cost in New Hampshire
At $40 to $80 per square foot of deck installed, a 320 sq ft job comes to $12,800–$25,600 at national rates. Adjusted for local carpenters wages it is $12,750–$25,550 in Southwestern New Hampshire nonmetropolitan area and $13,650–$27,300 in Boston-Cambridge-Newton, MA-NH.
Checked October 20, 2026 · sources
- 1Composite, US $12,800–$25,600
- 2Lowest NH area $12,750–$25,550
- 3Highest NH area $13,650–$27,300
Price in each New Hampshire labor area
Labor is about 28% of this material's installed price at national rates, so a labor index of +10% moves the total by roughly 2.8%. The carpenters index runs from −1.0% to +24.2% across the state.
| Area | Labor index | Low | High | Midpoint |
|---|---|---|---|---|
| United States | ±0.0% | $12,800 | $25,600 | $19,200 |
| New Hampshire (statewide) | +1.0% | $12,850 | $25,650 | $19,250 |
| Manchester-Nashua | +1.2% | $12,850 | $25,700 | $19,250 |
| Boston-Cambridge-Newton | +24.2% | $13,650 | $27,300 | $20,500 |
| Central NH | +1.3% | $12,850 | $25,700 | $19,250 |
| Northern NH | +1.2% | $12,850 | $25,700 | $19,250 |
| Southwestern NH | −1.0% | $12,750 | $25,550 | $19,150 |
* No BLS estimate for carpenters in that area; statewide median used.
By size
| Deck area (sq ft) | National | Southwestern NH | Boston-Cambridge-Newton |
|---|---|---|---|
| 144 sq ft | $5,750–$11,500 | $5,750–$11,500 | $6,150–$12,300 |
| 240 sq ft | $9,600–$19,200 | $9,550–$19,150 | $10,250–$20,500 |
| 320 sq ft | $12,800–$25,600 | $12,750–$25,550 | $13,650–$27,300 |
| 400 sq ft | $16,000–$32,000 | $15,950–$31,900 | $17,050–$34,150 |
Against the other deck materials
Composite deck is the most expensive option here at the midpoint. National ranges for 320 sq ft:
- Pressure-treated pine deck: $8,000–$16,000
- Cedar deck: $9,600–$15,050
Composite deck in towns with a permit page
| Town | Labor area | Estimate | Permit |
|---|---|---|---|
| Barnstead | Central NH | $12,850–$25,700 | $50 |
| Conway | Northern NH | $12,850–$25,700 | $219 |
| Durham | Boston-Cambridge-Newton | $13,650–$27,300 | $193.34 |
| Exeter | Boston-Cambridge-Newton | $13,650–$27,300 | $152.38 |
| Fitzwilliam | Southwestern NH | $12,750–$25,550 | $146 |
| Goffstown | Manchester-Nashua | $12,850–$25,700 | $40 |
| Lebanon | Northern NH | $12,850–$25,700 | $204.75 |
| Londonderry | Boston-Cambridge-Newton | $13,650–$27,300 | $188.81 |
| Manchester | Manchester-Nashua | $12,850–$25,700 | $192.63 |
| Merrimack | Manchester-Nashua | $12,850–$25,700 | $252.60 |
| New Ipswich | Manchester-Nashua | $12,850–$25,700 | $64 |
| Newbury | Central NH | $12,850–$25,700 | $164 |
| Newport | Southwestern NH | $12,750–$25,550 | $114 |
| Portsmouth | Boston-Cambridge-Newton | $13,650–$27,300 | $165 |
| Rochester | Boston-Cambridge-Newton | $13,650–$27,300 | $199 |
| Salem | Boston-Cambridge-Newton | $13,650–$27,300 | $128 |
| Somersworth | Boston-Cambridge-Newton | $13,650–$27,300 | $209.29 |
The town pages quote each schedule's own wording. For the arithmetic behind a contractor's number, see how contractors price a roof and how to compare three quotes; back to deck building cost.
Sources
- HomeGuide: Cost to build a deck (Feb 10, 2026) — “Composite $40 – $80 (installed, per sq ft)”.
- Labor: HomeGuide: Cost to build a deck (Feb 10, 2026) — “The labor cost to build a new deck is $11 to $22 per square foot.”.
- Wages: O*NET OnLine, Carpenters (47-2031.00), New Hampshire local wages; areas: BLS, May 2025 Metropolitan and Nonmetropolitan Area Definitions.
Ranges built from published averages, not quotes. Cost by Town does not perform or arrange work.