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
Total area: 192 square feet
Your Deck Estimate
Pricing estimate based on current material costs and labor rates
Cost Breakdown
Project Details
*Estimates are approximate. Final pricing may vary based on site conditions, local codes, and material availability.
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.