Lumber for a 10×12 Deck
Free calculator with pre-filled dimensions • Updated March 2026
A 10×12 deck needs approximately 120 board feet of decking plus framing lumber — about $800–$1,200 in materials.
Open calculator with these dimensions →10×12 Deck Lumber: Complete Material List
A 10×12 deck (120 sq ft) is a popular starter deck size — large enough for a table and 4 chairs with room to move. Here is a complete lumber and hardware breakdown for pressure-treated pine or cedar construction.
Material List
| Item | Size | Qty | Cost (2026) |
|---|---|---|---|
| Decking boards | 5/4×6×12' | 17 boards | $170–$340 |
| Joists | 2×8×12' | 8 joists (16" OC) | $96–$128 |
| Rim/band joists | 2×8×12' and 2×8×10' | 3 boards | $36–$48 |
| Beam | 2×8×12' (doubled) | 2 boards | $24–$32 |
| Posts | 6×6×8' | 3 posts | $60–$90 |
| Post bases | Simpson ABU66 | 3 pcs | $30–$45 |
| Joist hangers | Simpson LUS28 | 16 pcs | $48–$64 |
| Deck screws | #8×3" stainless | 5 lbs | $35–$50 |
| Lag bolts | 1/2"×6" | 8 pcs | $16–$24 |
Total materials: $515–$820 for pressure-treated pine. Composite decking (Trex, TimberTech) doubles the decking board cost.
Framing Layout
The 12-foot dimension runs parallel to the house (ledger side). Joists span the 10-foot width at 16 inches on center, supported by a beam at approximately 5 feet from the ledger. Three 6×6 posts support the beam, spaced at 6 feet apart.
Pro Tips
- Use 16" joist spacing for 5/4 decking. If using full 2×6 decking, you can space joists at 24" OC, saving 2–3 joists. Composite decking manufacturers specify maximum joist spacing — check before framing.
- Pre-drill near board ends. Deck screws within 2 inches of a board end will split the wood if not pre-drilled, even in pressure-treated lumber.
- Leave 1/8" gaps between decking boards for drainage and seasonal expansion. Use a 16d nail as a spacer.
Frequently Asked Questions
How much does lumber cost for a 10×12 deck?
Pressure-treated pine lumber for a 10×12 deck costs $515–$820 in 2026 including decking, framing, and hardware. Composite decking (Trex, TimberTech) adds $300–$500 for the deck boards alone.
How many deck boards for a 10×12 deck?
Using 5/4×6×12-foot boards running the 12-foot length, you need 17 boards (allowing for 1/8-inch gaps between boards). Buy 18–19 boards to account for waste and warped boards.
What size joists for a 10×12 deck?
2×8 joists are appropriate for a 10-foot span at 16 inches on center. For a 10-foot span with composite decking, 2×8 at 12-inch spacing may be required — check the decking manufacturer specs.