Cost to Build a 16x20 Deck: Complete 2026 Pricing Guide
How much does a 16x20 deck cost in 2026? Full cost breakdown by material type -- pressure-treated wood, composite, cedar -- plus labor, railing, stairs, DIY savings, and regional pricing.
How Much Does a 16x20 Deck Cost to Build?
A 16x20-foot deck (320 sq ft) costs between $7,500 and $18,000 to build in 2026, with the national average around $11,500 for pressure-treated wood with basic railing and two sets of stairs. This mid-size deck is one of the most popular sizes -- big enough for dining and lounging but not so large that it requires engineering permits in most jurisdictions.
Cost by Material Type (320 sq ft)
| Deck Material | Material Cost | Installed Cost | Cost per Sq Ft |
|---|---|---|---|
| Pressure-Treated Pine | $3,800 -- $6,500 | $7,500 -- $12,500 | $23 -- $39 |
| Cedar | $5,500 -- $9,000 | $10,000 -- $16,000 | $31 -- $50 |
| Composite (Trex, TimberTech) | $8,000 -- $14,000 | $13,000 -- $22,000 | $41 -- $69 |
| PVC / Premium Composite | $11,000 -- $18,000 | $17,000 -- $28,000 | $53 -- $88 |
| Ipe / Tropical Hardwood | $10,000 -- $19,000 | $16,000 -- $30,000 | $50 -- $94 |
Pressure-treated pine keeps the project under $12,500 for most homeowners, while composite adds roughly $5,000 to $7,000 upfront but saves $300-$500 per year in maintenance costs.
Full Cost Breakdown (16x20 Pressure-Treated Deck)
| Line Item | Cost |
|---|---|
| Footings (6-8 concrete piers @ $50-$80 each) | $300 -- $640 |
| Framing lumber (2x8 and 2x10 joists) | $1,100 -- $1,800 |
| Decking boards (5/4x6 pressure-treated) | $950 -- $1,600 |
| Railing (42 linear ft, code-compliant) | $900 -- $2,200 |
| Two sets of stairs (4-riser each) | $600 -- $1,200 |
| Fasteners, brackets, hardware | $350 -- $600 |
| Permit + inspection | $200 -- $500 |
| Labor (40-60 hours @ $50-$80/hr) | $2,000 -- $4,800 |
| Total Installed | $6,400 -- $13,340 |
DIY vs. Professional Installation
| DIY | Professional | |
|---|---|---|
| Material cost | $3,800 -- $6,500 | Included in quote |
| Labor | Your time (60-100 hours) | $2,000 -- $4,800 |
| Total | $3,800 -- $6,500 | $7,500 -- $12,500 |
| Timeline | 3-6 weekends | 1-2 weeks |
| Risk | Structural errors, code violations | Warranty, licensed work |
DIY saves $3,700 to $6,000 on a 16x20 pressure-treated deck, but requires intermediate carpentry skills, a helper, and knowledge of local building codes. Get precise estimates with our deck building cost calculator.
Regional Cost Differences (16x20 Pressure-Treated)
| Region | Installed Cost Range | Notes |
|---|---|---|
| Southeast | $6,500 -- $10,000 | Lower labor rates, competitive market |
| Midwest | $7,000 -- $11,500 | Moderate rates, ample contractor supply |
| Northeast | $9,500 -- $14,000 | High labor, strict codes, frost footings |
| Southwest | $7,000 -- $11,000 | Dry climate reduces rot concerns |
| West Coast | $10,000 -- $16,000 | Premium labor, seismic codes |
When to Hire a Professional
- Your deck is more than 30 inches above grade (railing + structural code applies)
- You need a permit and stamped engineering drawings
- You're using composite or PVC (warranty often requires professional installation)
- The ground slopes more than 12 inches across the deck footprint
- You want it done in under 2 weeks
Common Mistakes to Avoid
- Undersized footings -- a 16x20 deck needs 6-8 footings below frost line, not just deck blocks on grass.
- Wrong joist spacing -- 16-inch on-center for 5/4 boards; 24-inch for 2x6 decking. Composite requires 12-inch spacing.
- No flashing at the ledger -- water intrusion at the house connection is the #1 cause of deck failure.
- Skipping the permit -- unpermitted decks can kill a home sale and may need to be torn down.
FAQ
Q: Do I need a permit for a 16x20 deck?
A: Almost always yes. Most municipalities require permits for any deck over 30 inches high or over 200 sq ft. A 16x20 deck at 320 sq ft exceeds both common thresholds.
Q: How long does a 16x20 deck take to build?
A: Professionals finish in 5-10 working days. DIY with a helper takes 3-6 weekends depending on experience level.
Q: What's the ROI on a 16x20 deck?
A: National average ROI is 65-75% for wood and 60-70% for composite, per Remodeling Magazine's Cost vs. Value report. Decks consistently rank among the top 5 home improvement projects for resale value.
Q: Composite vs. wood for a 16x20 deck -- which is better?
A: Wood costs 40-50% less upfront. Composite pays off after 8-12 years when you factor in staining, sealing, and occasional board replacement. For a long-term home, composite wins; for a 5-year home, go wood.
*Last updated: July 9, 2026. Estimates based on U.S. national averages. Always get 3 local quotes for your specific project location.*