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Calculate all materials needed for your deck project including decking boards, joists, beams, posts, hardware, railings, and stairs. Get accurate estimates for lumber, concrete, and fasteners.
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Standard board width is 5.5" (nominal 6") with 1/8" gap between boards.
Standard spacing is 16" O.C., use 12" for diagonal patterns.
Posts typically spaced 6-8' apart along each beam.
Ideal riser is 7", code allows 4-7.75". Tread depth minimum 10".
| Material | Cost/sq ft | Lifespan | Maintenance |
|---|---|---|---|
| Pressure-Treated Pine | $2-4 | 15-20 years | Stain/seal every 2-3 years |
| Cedar | $4-6 | 15-25 years | Stain every 3-5 years |
| Redwood | $6-10 | 20-30 years | Minimal, seal optional |
| Composite | $6-12 | 25-30 years | Minimal cleaning only |
| PVC/Plastic | $8-14 | 30+ years | None required |
| Ipe (Hardwood) | $12-20 | 40+ years | Oil annually for color |
Most residential decks use 5/4×6 (1" × 5.5" actual) or 2×6 (1.5" × 5.5" actual) boards. Composite decking typically comes in 6" width. Wider boards are harder to keep flat and may cup over time.
16" on center is standard for most decking. Use 12" O.C. for diagonal decking patterns or thinner boards. Composite decking may allow 16" or even 24" depending on the product - always check manufacturer specifications.
Post holes should extend below the frost line (varies by region, typically 36-48") plus 6" for gravel drainage. Posts should be embedded at least 1/3 of their length. Check local building codes for specific requirements.
For a standard 10" diameter × 42" deep hole, you need about 2-3 bags of 60lb or 80lb concrete mix. Use pre-mixed bags for convenience, or calculate volume: π × r² × depth = cubic feet, then convert to bags (1 bag ≈ 0.45-0.6 cu ft yield).
Most areas require a permit for decks over 200 sq ft, elevated more than 30" above grade, or attached to the house. Permits ensure proper construction, especially for structural elements like ledger boards, posts, and railings. Always check local building codes.
Leave 1/8" to 1/4" gap between boards for drainage and expansion. Use a 16d nail or spacer for consistent gaps. Composite decking may have specific gap requirements - check the manufacturer's installation guide.