How much does it cost to build a deck per square foot?

A basic pressure-treated wood deck costs $15–30 per sq ft installed. A composite deck runs $35–65 per sq ft. A premium hardwood or high-end composite deck can reach $70–100+ per sq ft. Additional features like multiple levels, built-in seating, or elaborate railing systems increase the cost per square foot significantly.

Do I need a permit to build a deck?

In most US jurisdictions, yes. Permits are typically required for attached decks, elevated decks (30 inches or more above grade), and decks of any size in many areas. Check with your local building department. Unpermitted decks can affect home sales, insurance claims, and your liability if someone is injured.

What is the best deck material for low maintenance?

Capped composite decking (brands like Trex Transcend, TimberTech Azek, Fiberon Symmetry) requires the least maintenance — just occasional soap and water cleaning. No staining, sealing, or sanding required. Though expensive upfront, the total cost of ownership over 20+ years is often lower than wood when maintenance labor and materials are factored in.

How far apart should deck joists be?

Standard deck joist spacing is 16 inches on center for most decking boards laid perpendicular to the joists. Diagonal decking patterns and most composite decking products require 12-inch spacing. Always check the decking manufacturer's installation guide — using incorrect joist spacing voids the product warranty.

How long does a wood deck last?

A pressure-treated pine deck, properly maintained with regular staining and sealing, lasts 15–25 years. Cedar and redwood decks last 20–30 years. The deck surface boards typically need replacement before the structural framing. With a composite deck, boards can last 25–50 years; the pressure-treated framing beneath typically lasts 30+ years.

Deck Building Guide: Materials, Cost & Calculator (2026)

Deck Cost by Material (2026)

Deck costs vary significantly based on decking material, framing, footings, railing, and labor. Here are typical installed costs per square foot of deck surface:

Pressure-treated pine: $15–$30 per sq ft installed. Most economical choice. Requires staining/sealing every 1–2 years to prevent warping, splitting, and graying. Requires proper fasteners (hot-dipped galvanized or stainless steel) as standard zinc-plated fasteners corrode in treated wood.
Cedar and redwood: $25–$45 per sq ft installed. Naturally rot and insect resistant. Beautiful grain. More dimensionally stable than pine. More expensive but less chemical treatment.
Composite decking: $35–$65 per sq ft installed. Made from wood fiber and recycled plastic. Very low maintenance (no staining required). Wide variety of colors and wood-grain finishes. Warranty periods of 25–30 years. Best long-term value for many homeowners.
PVC/capped composite: $45–$75 per sq ft installed. Fully capped with protective polymer shell. Stain, scratch, and fade resistant. Premium pricing but minimal ongoing maintenance costs.
Tropical hardwood (ipe, tigerwood): $30–$60 per sq ft for materials alone. Extremely dense, naturally resistant to rot, insects, and fire. Very long lifespan. Requires pre-drilling for all fasteners due to hardness. Sustainability concerns for some species.

Framing and Joist Spacing

The framing is as important as the decking surface. Standard deck joists are 2×8 or 2×10 lumber (pressure-treated) spaced 12 or 16 inches on center:

12-inch spacing: Required for diagonal decking patterns and most composite decking products. Provides stiffer feel underfoot. Requires roughly 30% more lumber than 16-inch spacing.
16-inch spacing: Standard for horizontal hardwood or solid composite decking. Most common framing for residential decks.
24-inch spacing: Not recommended for residential decking — feels bouncy and may not meet code for expected live load requirements.

Always consult the decking manufacturer's installation guide for required joist spacing — composite decking products vary by brand, and using incorrect spacing voids the warranty.

Ledger Attachment

Decks attached to the house connect through a ledger board — a horizontal 2× board bolted directly to the house rim joist. Proper ledger attachment is critical: deck collapses are most commonly caused by ledger failure. Key requirements:

Use structural lag screws (1/2 inch diameter minimum) or through-bolts in a staggered pattern per code
Install deck flashing over and behind the ledger to prevent water infiltration into the house framing
Remove any siding, trim, and housewrap from the ledger contact area before attachment
Free-standing decks (not attached to the house) require additional footings but avoid ledger concerns entirely

Footings: The Foundation of Your Deck

Deck posts must rest on concrete footings that extend below the frost line. Frost depth varies from 12 inches in the deep south to 48+ inches in northern climates. Check your local building department for the required depth. Footings must also be sized for the load they carry — a 10-foot tributary area post typically needs a 12–16 inch diameter footing.

Pre-cast deck blocks (surface-mounted) are allowed in some jurisdictions for free-standing low-level decks but are not suitable for elevated or attached decks in most codes.

Railing Requirements

Building codes require guardrails on decks 30 inches or more above grade (in many jurisdictions, 24 inches). Key requirements typically include:

Minimum rail height: 36 inches (42 inches for decks over 30 feet above grade in some codes)
Maximum baluster spacing: 4 inches clear (so a 4-inch sphere cannot pass through)
Rail posts must be structurally adequate to withstand 200 lbs lateral force

Railing adds $35–80 per linear foot installed (wood) or $60–130 per linear foot for composite or cable railing systems.

Permits and Inspections

Building permits are required in virtually all US jurisdictions for decks attached to the house and for elevated decks. The permit process ensures your deck is structurally safe and legally sellable. Unpermitted decks can complicate home sales and insurance claims. Permit fees typically run $150–500. Inspections occur at footings (before concrete), framing, and completion.