The numbers Long Island homeowners actually need
Adding a wood deck on Long Island typically costs $18–$38 per square foot fully installed, meaning a standard 400 sq ft deck runs $7,200–$15,200 depending on material, site conditions, and whether you need permits and footings. That range is real — the same 16x20 deck built in pressure-treated pine costs about half what it costs in ipe or Brazilian teak, and permits add time and money that some out-of-state cost guides completely ignore.
Here's a full breakdown by material, size, and the local factors that move Long Island deck prices specifically.
Cost by material: the biggest variable
The wood you choose drives more of the final price than almost anything else. Here's what each material actually costs on Long Island jobs we've priced in 2025–2026.
Pressure-treated pine
The most common entry-level choice. New ACQ treatment (the modern arsenic-free formula) is durable, takes stain well, and holds up in Long Island's climate if maintained. Decking boards run $3–$5/linear foot at local suppliers (Lumbermen's in Huntington, Island Ready Mix in Medford).
- Installed cost: $18–$26/sq ft
- 400 sq ft deck: $7,200–$10,400
- Expected lifespan with maintenance: 15–25 years
- Annual maintenance: stain every 2–3 years, ~$400–$700 for a 400 sq ft deck
Cedar
Western red cedar has natural oils that resist rot and insects without chemical treatment. It's the upgrade from PT that most Long Island homeowners who care about aesthetics make first. Looks better right off the saw, takes stain cleanly, lighter than ipe.
- Installed cost: $24–$34/sq ft
- 400 sq ft deck: $9,600–$13,600
- Expected lifespan with maintenance: 20–30 years
- Annual maintenance: stain every 2–3 years, similar to PT
Ipe (Brazilian hardwood)
Ipe (pronounced "ee-pay") is the premium hardwood option — Janka hardness rating of 3,684 compared to 1,225 for white oak. It's naturally resistant to rot, insects, and fire, requires no chemical treatment, and turns a silver-grey without oil but maintains the deep brown with annual oiling. The tradeoff is cost and workability — it needs pre-drilling for every fastener.
- Installed cost: $32–$50/sq ft
- 400 sq ft deck: $12,800–$20,000
- Expected lifespan: 40–75 years with minimal maintenance
- Annual maintenance: oil once a year, ~$200–$400
Composite decking (for comparison)
Not wood, but the most popular material we spec today — primarily TimberTech AZEK and Trex Transcend. Capped composite eliminates the stain schedule entirely and performs well in Long Island's salt air and freeze-thaw cycles.
- Installed cost: $35–$55/sq ft
- 400 sq ft deck: $14,000–$22,000
- Expected lifespan: 25–50 years, typically manufacturer-warranted
- Annual maintenance: soap and water
What drives cost beyond the material
Deck size and shape
Simple rectangular decks are the cheapest per square foot. Every angle cut, notch, or fascia detail adds labor time. A 400 sq ft L-shaped deck costs more per square foot than a 400 sq ft rectangle.
Height off grade
A ground-level deck (under 30 inches) is simpler and cheaper — lighter framing, no railing required by code in many cases. A second-story deck or elevated deck requires full structural framing, footings below frost line (42 inches in Nassau/Suffolk), and guardrails meeting IRC code. Add $3,000–$8,000 for a full elevated structure.
Footings and foundation
All decks on Long Island require footings below frost line — 42 inches minimum. The number of footings depends on deck size and design loads. Typical footing cost: $150–$300 per footing, most decks require 4–10 footings. If your soil is sandy or saturated (common near the South Shore bays), footings may need to go deeper or wider.
Railings
Code requires railings on any deck surface more than 30 inches above grade. Wood railings to match the decking add $65–$95/linear foot installed. Cable railing (stainless steel cables in wood or aluminum posts) runs $120–$180/linear foot and is popular on Long Island waterfront properties for the view-through effect.
Stairs
A standard straight staircase adds $800–$2,500 depending on run and number of steps. L-shaped stairs with a landing cost $2,000–$4,500.
Built-in features
Built-in benches add $400–$900 per bench. Planters add $300–$700 each. Pergolas are a separate scope: $3,500–$12,000 depending on size and material.
Nassau County vs. Suffolk County permit costs
This is where Long Island deck pricing diverges from national cost guides, which typically assume permit costs of $150–$400. Long Island municipalities charge more and require more documentation than average.
Nassau County towns (Hempstead, North Hempstead, Oyster Bay)
- Building permit: $300–$600 for most residential decks
- Zoning review for setback compliance: included but adds processing time
- Survey required if expanding impervious coverage: $650–$1,200
- Typical permit timeline: 3–8 weeks
Suffolk County towns (Huntington, Smithtown, Babylon, Brookhaven, Islip)
- Building permit: $250–$500
- Typical permit timeline: 2–6 weeks
- Some towns (Huntington, Brookhaven) require architect-stamped plans for elevated decks over a certain size
We pull all permits as part of our build — it's included in the quote, not a surprise line item. The permit timeline is part of why "we can start next week" from an unlicensed contractor is a red flag. Anyone doing a permitted deck has a processing queue to wait through.
What does the installation process actually look like?
Most residential wood decks in the 300–600 sq ft range take our crew 3–5 days from first footing pour to final inspection:
- Day 1: Layout, footing excavation, concrete pour. Footings cure for 24–48 hours.
- Day 2: Frame installation — beams, joists, blocking.
- Day 3–4: Decking installation, fascia, stairs.
- Day 5: Railings, final cleanup, call-out for inspection.
Permit inspection happens at footings (before pour), framing (before decking), and final. We coordinate all three.
How to evaluate a deck quote
When you're comparing quotes on Long Island, check for these specifics:
- Does the quote include permits and inspections, or are those extra?
- What lumber grade is specified? (Look for #1 or better pressure-treated, not #2 or "construction grade")
- What fastener system? Hidden fasteners cost more but eliminate surface screw holes — worth asking about for cedar and composite
- What footing depth? Should say 42 inches minimum for Long Island
- Is there a warranty on labor separate from the material warranty?
The lowest quote often omits permits (meaning the deck is unpermitted, which creates problems at resale) or uses lower lumber grades that shorten the deck's life.
Get a written estimate
We do free, in-person quotes for decks across Nassau and Suffolk County — written, itemized, good for 30 days. Call us at the number above or use the form on our estimate page to schedule. Most estimates are completed within 48 hours of the site visit, and permits are something we've already pulled in your specific municipality — we know the process cold.