Materials for a 10×12 Deck
Free calculator with pre-filled dimensions • Updated March 2026
A 10×12 deck needs 29 decking boards (5.5" wide, 12 ft long with 10% waste), 9 joists, 6 posts, and about $800–$1,200 in materials for pressure-treated wood.
Open calculator with these dimensions →10×12 Deck: Complete Material Guide
A 10×12 foot deck (120 sq ft) is the most popular starter deck size — fits a dining table for four with room to grill. This guide covers every material you need from footings to finish.
Complete Material List
| Item | Qty | PT Pine Cost | Composite Cost |
|---|---|---|---|
| Decking boards (5/4×6×12') | 17 | $170–$340 | $510–$850 |
| Joists (2×8×10') | 8 | $80–$112 | $80–$112 |
| Ledger + rim joists | 3 boards | $36–$48 | $36–$48 |
| Beam (doubled 2×8×12') | 2 | $24–$32 | $24–$32 |
| Posts (6×6×8') | 3 | $60–$90 | $60–$90 |
| Post footings (Deck blocks or sono tubes) | 3 | $30–$75 | $30–$75 |
| Joist hangers | 16 | $48–$64 | $48–$64 |
| Deck screws (stainless) | 5 lbs | $35–$50 | $55–$80 |
| Ledger flashing | 12 ft | $15–$25 | $15–$25 |
PT pine total: $500–$840. Composite total: $860–$1,380.
Pro Tips
- Attach the ledger properly. The ledger board is the most critical connection. Lag bolt it to the house rim joist (not just siding) with 1/2"×4" lag screws at 16" OC, and install Z-flashing above to prevent water infiltration.
- Crown joists up. Lumber has a natural bow. Place each joist with the crown (convex side) facing up so loads push it flat rather than increasing the bow.
- Composite decking needs hidden fasteners. Don't face-screw composite boards — it looks terrible and voids many warranties. Use the manufacturer's hidden clip system.
Frequently Asked Questions
How much does a 10×12 deck cost?
DIY materials: $500–$840 for pressure-treated pine, $860–$1,380 for composite decking. Professional installation adds $1,500–$3,000 in labor for a total of $2,000–$4,400.
Do I need a permit for a 10×12 deck?
In most areas, yes — decks attached to the house or over 30 inches above grade require a building permit. Some jurisdictions exempt small freestanding decks under 200 sq ft. Check with your local building department.