Composite Deck Calculator
Calculate composite decking boards and material cost for your deck project.
Formula & Explanation
The composite deck calculator determines materials and cost for composite deck surfaces. Boards Needed = (Deck Area) ÷ [(Board Width + Gap) × Board Length] × (1 + Waste%) Material Cost = Deck Area × Price per Square Foot Composite decking is made from wood fiber and recycled plastic, offering durability without the maintenance of pressure-treated wood. It resists rot, insects, and fading, though it costs more upfront ($8-15/sqft vs $3-6/sqft for wood). Waste allowance for composite is typically 5-10% (smaller than wood since it doesn't expand/contract as much).
Assumptions
- •Composite board width and gap are in inches; deck dimensions in feet
- •Price per square foot is for materials only (installation not included)
- •Waste allowance is 5-10% for composite (less than pressure-treated wood)
- •Gap size for composite is typically 1/16" to 1/8" (check manufacturer specs)
- •Boards must fit within deck dimensions; cutting optimization not applied
- •Cost does not include framing, fasteners, labor, or accessories
Example Calculation
A 20x15 composite deck with 5.5" boards at $12/sqft requires 49 boards and costs $3,600 in materials.
Inputs
Results
Composite Decking Brands and Price Ranges
| brand | pricePerSqFt | warranty | type |
|---|---|---|---|
| Trex (Transcend) | $10-14 | 25-30 years | Solid |
| Trex (Select) | $8-10 | 15-20 years | Solid |
| TimberTech | $9-13 | 20-30 years | Hollow |
| Azek | $11-15 | 20-30 years | Solid |
| Fiberon | $8-12 | 15-20 years | Hollow |
| Composite average | $8-14 | 15-30 years | Mixed |
| Pressure-treated wood | $3-6 | Varies (10+ years) | Natural |
Frequently Asked Questions
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