Deck Build Cost Calculator

Typical 16×20 ft deck cost ranges: pressure-treated wood $5,000-$9,000, cedar $7,000-$13,000, composite (Trex/TimberTech) $11,000-$22,000, IPE/tropical hardwood $20,000-$35,000. Labor runs 60-70% of materials. Adding stairs adds $1,500-$3,000 each; railing adds $25-$50/linear ft. Decks over 30" off the ground typically require permits and engineered footings, adding $1,000-$3,000.

Composite (Trex, TimberTech, Fiberon) costs 2-3× pressure-treated upfront but lasts 30+ years with zero maintenance vs PT's 20-year life requiring annual cleaning + biennial staining. Lifetime cost is similar or composite wins, but you pay the difference upfront. Best fit for composite: humid climates, heavy UV exposure, busy households. PT still wins for budget projects or detached decks with limited use.

Most jurisdictions require a permit for decks over 30" off the ground OR over 200 sq ft OR attached to the house. Ground-level freestanding patios under 200 sq ft often don't require permits. Always check local code - unpermitted decks become serious liability at resale and can void homeowners insurance claims. Permit costs: $200-$800 typical; HOA approval separate.

Composite requires tighter joist spacing - 12" on-center vs 16" for wood - because composite is more flexible. Most manufacturers also require hidden fasteners (no visible screws), specific board spacing for thermal expansion, and ventilation under the deck. Skip these and the warranty is voided. Substructure cost is 15-25% higher than wood as a result.