Composite Decking Calculator

The Low-Maintenance Revolution: Composite Decking Guide

Composite decking (like Trex, TimberTech, or Fiberon) has revolutionized outdoor living. Made from a blend of recycled plastic and wood fibers, it offers the look of wood without the rotting, warping, or splintering. However, it is fundamentally different to install than traditional pressure-treated lumber. This guide helps you plan your materials accurately.

1. Board Width & Spacing

Standard Width: Most composite boards are nominally 5.5 inches wide.
Gapping: Unlike wet pressure-treated wood (which shrinks), composite expands and contracts with heat. You must leave a consistent gap (usually 3/16" to 1/4") for drainage and debris.
Pro Tip: Using "Hidden Fasteners" (clips) automatically sets the perfect gap between boards.

2. Calculating Material Needs

To avoid running short in the middle of a project, accuracy is key.
Square Footage Method: Calculate Total Sq Ft / Sq Ft per Board.
Linear Method (More Accurate): Calculate (Deck Width / Board Width + Gap) to find rows, then multiply by Deck Length.
Waste Factor: Always add 10-15% for cuts, mistakes, and bad ends. Our calculator adds a standard 10% safety margin.

3. Hidden Fasteners vs. Screws

Face Screwing: The old school way. You screw right through the top. This is cheaper but leaves visible screw heads that trap water (and look ugly). You must use "Composite Screws" designed to prevent mushrooming.
Hidden Fasteners (Clips): These clips slide into the groove on the side of the board and screw into the joist. They are invisible from the top.
Usage Rate: Approximately 1.75 clips per square foot (assuming 16" joist spacing).

4. Cost Comparison

Is it worth it?
Pressure Treated: ~$1.50 - $2.50 per linear foot. Lasts 10-15 years with yearly staining.
Composite (Good): ~$3.50 - $5.00 per linear foot. Lasts 25+ years. No staining.
Composite (Best / PVC): ~$6.00 - $9.00 per linear foot. Superior heat dissipation and grain validation.