Composite Decking Calculator
Estimated Total Cost
$1,320 – $2,200
$6.60 – $11.00 per sq ft • 220 sq ft (incl. 20 sq ft waste)
Decking Material
$1,100 – $1,760
Fasteners
$220 – $440
Boards Needed (12 ft)
40 boards
Maintenance Savings: Composite decking never needs staining, sealing, or painting. Over 25 years, you’ll save $2,000–$5,000 in maintenance costs compared to pressure-treated wood. The higher upfront cost pays for itself within 8–12 years.
Permit Notice: Most municipalities require a building permit for decks over 200 sq ft or higher than 30 inches above grade. Permit fees typically run $75–$500. Check with your local building department before starting construction.
Warranty: Mid-Range composite boards (Trex Select, TimberTech Edge) typically carry a 25-year limited warranty covering structural integrity, staining, and fading. Always register your warranty with the manufacturer after installation.
Hidden Fasteners: Hidden clip systems create a smooth, screw-free surface. They auto-space boards for drainage and allow expansion/contraction. Most composite manufacturers recommend hidden fasteners for the best appearance and warranty compliance.
Disclaimer: Estimates are for budgeting purposes only. Actual costs vary by location, contractor, material availability, and project complexity. Always get professional quotes for exact pricing.
Composite Decking Cost Breakdown
Composite Decking Cost by Tier (Material Only)
| Tier | Cost / Sq Ft | Example Brands | Warranty |
|---|---|---|---|
| Budget | $3 – $5 | MoistureShield, NewTechWood | 25 years |
| Mid-Range | $5 – $8 | Trex Select, TimberTech Edge | 25 years |
| Premium | $8 – $12 | Trex Transcend, TimberTech Pro | 50 years |
| Luxury | $12 – $18 | Azek, TimberTech Legacy | 50 years |
* Material cost only. Does not include fasteners, substructure, railing, or labor.
Total Composite Deck Cost by Size (Mid-Range Tier, DIY Material Only)
| Deck Size | Area (sq ft) | Boards (12 ft) | Material Cost |
|---|---|---|---|
| Small (10 × 10) | 100 | 20 | $550 – $880 |
| Medium (10 × 20) | 200 | 40 | $1,100 – $1,760 |
| Large (20 × 20) | 400 | 80 | $2,200 – $3,520 |
| Wraparound | 600 | 120 | $3,300 – $5,280 |
* Mid-range tier ($5–$8/sf) with 10% waste factor and standard 5.5" boards. Add fasteners, substructure, and railing separately.
Composite vs. Wood Decking: 25-Year Cost Comparison
| Cost Factor | Composite (Mid-Range) | Pressure-Treated Wood |
|---|---|---|
| Material cost (200 sf) | $1,100 – $1,760 | $400 – $1,000 |
| Annual maintenance | $0 (wash only) | $100 – $300/yr (stain + seal) |
| 25-year maintenance | $0 | $2,500 – $7,500 |
| Replacement needed? | No (25–50 yr lifespan) | Likely at 10–15 years |
| 25-year total cost | $1,100 – $1,760 | $3,300 – $9,500+ |
* Based on a 200 sq ft deck. Wood costs include one deck replacement and biannual staining. Composite requires only occasional cleaning.
How We Calculate
Our composite decking calculator estimates the total material cost, board count, fastener cost, substructure cost, and railing cost based on your deck area, composite tier, board width, and project options.
How the math works: Total area = deck area + 10% waste factor. Boards needed = total area ÷ coverage per 12-foot board. Material cost = total area × cost per sq ft for the selected tier. Fastener cost = total area × fastener cost per sq ft. Substructure cost = deck area × $3–$6/sf (if new). Railing cost = estimated railing linear feet × $20–$60/lf.
Composite Tier Comparison
Budget ($3–$5/sf): MoistureShield, NewTechWood — wood-plastic composite, 25-year warranty. Mid-Range ($5–$8/sf): Trex Select, TimberTech Edge — capped composite, 25-year warranty. Premium ($8–$12/sf): Trex Transcend, TimberTech Pro — capped composite, 50-year warranty. Luxury ($12–$18/sf): Azek, TimberTech Legacy — capped polymer (PVC), 50-year warranty, fully moisture-proof.
Board Width & Coverage
Standard boards are 5.5″ wide (5.5 sq ft per 12-ft board). Wide boards are 7.25″ wide (7.25 sq ft per 12-ft board). Wide boards cover more area per board, reducing installation time and the number of fastener rows. Both widths are available in 8, 12, 16, and 20-foot lengths.
Waste Factor
We include a 10% waste factor for standard (parallel) board layouts. If your deck has angled patterns, picture framing, or complex shapes, increase to 15% waste. Waste accounts for end cuts, board defects, and fitting around obstacles like posts and stair stringers.
Railing Estimate
Railing linear feet are estimated from the deck perimeter, minus one side for house attachment (approximately 75% of total perimeter). Composite railing systems cost $20–$60 per linear foot installed, including posts, top/bottom rails, balusters, and post caps. Aluminum and cable railing systems may cost more.
Data Sources
Pricing is compiled from manufacturer MSRP data (Trex, TimberTech, Azek, MoistureShield), verified against retail pricing at Home Depot, Lowe’s, and specialty decking suppliers. We review pricing quarterly. Actual costs vary by region, retailer, color selection, and seasonal promotions.
Last updated: 2026-02-08
Frequently Asked Questions
How much does composite decking cost per square foot? +
Composite decking materials cost $3–$18 per square foot depending on the tier. Budget brands (MoistureShield, NewTechWood) run $3–$5/sf, mid-range (Trex Select, TimberTech Edge) $5–$8/sf, premium (Trex Transcend, TimberTech Pro) $8–$12/sf, and luxury (Azek, TimberTech Legacy) $12–$18/sf. Add $0.50–$2.00/sf for fasteners and $3–$6/sf if you need a new substructure.
Is composite decking cheaper than wood in the long run? +
Yes. While composite decking costs 2–3 times more upfront than pressure-treated wood ($3–$18/sf vs. $2–$5/sf), it requires zero staining, sealing, or painting. Over 25 years, wood deck maintenance costs $2,000–$5,000+ in stain, sealant, and labor. Composite pays for itself in 8–12 years and lasts 25–50 years with minimal upkeep — just occasional soap-and-water cleaning.
How many composite deck boards do I need? +
Divide your total square footage (including 10% waste) by the coverage per board. A standard 5.5″-wide, 12-foot composite board covers about 5.5 sq ft. A wide 7.25″ board covers about 7.25 sq ft. For a 200 sq ft deck with 10% waste (220 sq ft total), you’ll need approximately 40 standard boards or 31 wide boards at 12-foot lengths.
What is the best composite decking brand? +
Trex and TimberTech are the two most popular composite decking brands in the US, together holding over 70% of the market. Trex Transcend and TimberTech Pro offer the best balance of price and performance with 50-year warranties. Azek (owned by TimberTech’s parent company) is the premium PVC choice for maximum moisture resistance. For budget projects, MoistureShield and NewTechWood offer solid 25-year warranties at lower price points.
Do I need a substructure for composite decking? +
Composite decking boards cannot support themselves — they always require a substructure (joists and beams). If you’re replacing existing wood deck boards on a sound frame, you can install composite directly on the existing joists (verify 16″ on-center spacing and structural integrity). For a new deck, budget $3–$6 per square foot for pressure-treated joists, beams, posts, and hardware.
Should I use hidden fasteners or face screws for composite decking? +
Hidden fasteners ($1–$2/sf) are recommended by most manufacturers for grooved-edge composite boards. They create a smooth, screw-free surface, auto-space boards for drainage, and allow thermal expansion. Face screws ($0.40–$0.60/sf) are cheaper and work on solid-edge boards or starter/perimeter boards. Many pros use hidden clips for the field and face screws at the perimeter.
How long does composite decking last? +
Composite decking lasts 25–50 years depending on the product tier. Budget composites carry 25-year warranties. Premium and luxury brands (Trex Transcend, Azek) carry 50-year limited warranties covering structural integrity, staining, and fading. By comparison, pressure-treated wood decking lasts 10–15 years with regular maintenance. Composite won’t rot, splinter, or attract termites.
Do I need a permit to build a composite deck? +
In most US municipalities, you need a building permit for any deck that is attached to the house, larger than 200 sq ft, or more than 30 inches above grade. Permit fees range from $75 to $500 depending on your location and deck size. The permit process typically requires a site plan, structural drawings, and inspections. Freestanding ground-level decks under 200 sq ft may be exempt — check your local building code.
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