Deck Cost Calculator, Composite & Pressure-Treated Pricing
Free deck cost estimator. Pick size, material, and features for instant per-square-foot pricing.
Deck Configuration
Customize your deck options to get an accurate estimate
Your Deck Estimate
Pricing estimate based on current material costs and labor rates
Understanding Your Deck Estimate
What's Included
- • All materials (lumber, fasteners, hardware)
- • Professional installation labor
- • Basic structural engineering
- • Standard building permits
- • Basic site preparation
- • Clean-up and disposal
Additional Considerations
- • Complex structural engineering may require additional fees
- • Prices may vary based on material availability
- • Site conditions may affect final pricing
- • Seasonal pricing fluctuations may apply
- • Custom designs may incur additional design fees
- • Electrical work requires licensed electrician
Deck Cost Calculator, FAQs
How much does it cost to build a 12×16 deck?
A standard 12×16 (192 sq ft) deck in Southern New Hampshire typically runs $5,500–$9,500 in pressure-treated lumber and $9,000–$16,000 in capped composite, fully installed. Pricing varies with footing depth, height off the ground, railing style, and access to the build site.
Composite vs. pressure-treated, what's the real cost difference?
Pressure-treated decking installs at roughly $25–$45 per square foot in NH. Capped composite (Trex, TimberTech, Deckorators) runs $45–$80 per square foot installed. Composite costs more upfront but eliminates annual staining and most board replacements over a 20–25 year span, so the lifetime cost usually favors composite for homeowners staying in the house long-term.
How much does a composite deck cost per square foot?
In the New Hampshire market, expect $45–$80 per square foot installed for capped composite. The low end uses entry-level boards with pressure-treated framing and standard railings; the high end uses premium boards (TimberTech AZEK, Trex Transcend), hidden fasteners, and aluminum or cable railings.
Does my New Hampshire deck need a building permit?
Yes. Most NH towns require a permit for any deck attached to the house or more than 30 inches off the ground, including Londonderry, Bedford, Plaistow, Salem, Derry, and Merrimack. Permits typically run $75–$300 and require a footing inspection. We pull permits as part of every deck build.
How long does a deck last in New England winters?
Properly built pressure-treated decks last 15–20 years before major board replacement; capped composite decks last 25–50 years and carry manufacturer warranties to match. Freeze-thaw cycles, ice melt, and snow loading are the main wear factors, which is why frost-depth footings (48 inches in most of NH) and proper flashing matter so much.
Is it cheaper to build a deck or a paver patio?
A ground-level paver patio is usually 20–40% cheaper than an equivalent-size deck because there are no footings, joists, or railings. But once a deck rises more than 30 inches off the ground, common on NH split-levels and walkouts, a deck becomes the only practical option. We often build hybrid designs that pair an upper composite deck with a lower paver patio.
New to hiring a deck builder in NH?
Read our 2026 buyer's guide for what to verify before you sign a contract.