Deck Board Calculator

How Deck Boards Are Measured and Ordered

Deck boards are sold by the linear foot or by the board (at a fixed length). To estimate how many you need, you calculate how many rows of decking run across the width of the deck, multiply by the deck's length to get linear feet, then divide by your board length to get board count. This calculator handles all of that automatically, including a 10% waste factor for end cuts.

Pressure-Treated vs. Composite Decking

The two most common decking materials UIR installs in Grayson County are pressure-treated lumber and composite decking. Each has different face widths, expansion behavior, and gap recommendations:

• 5/4×6 pressure-treated: 5.5" face, gap at installation ⅛" (expands in humidity)
• Trex, TimberTech, AZEK composite: 5" or 5⅜" face, gap per manufacturer (usually ⅛" to 3/16")
• 1×6 hardwood (Ipe, Cumaru): 5.5" face, very tight gaps, requires hidden fasteners

For lakefront properties near Nolin Lake and Rough River Lake, UIR strongly recommends composite over pressure-treated. Composite holds up to the moisture, UV exposure, and humidity swings that western Kentucky's lake environment delivers year-round. A pressure-treated deck at a lake cabin typically needs significant maintenance or replacement within 10–15 years; a composite deck is low-maintenance for 25+ years.

What This Calculator Doesn't Include

This calculator covers field decking only — the boards that span the surface. A complete deck order also includes:

• Fascia boards (the perimeter facing boards)
• Picture frame border boards (if using a border design)
• Hidden fasteners or screws
• Framing lumber (joists, beams, posts, ledger)
• Concrete for footings

Use the concrete calculator for your footing quantity. For a complete project estimate including all framing, hardware, and labor, contact UIR for a written quote. UIR has built decks of every size throughout Grayson County — from small 10×12 back porch additions to large multi-level lakefront structures with built-in benches, pergolas, and dock stairs.

Board Length Selection

Choosing the right board length minimizes waste and butt joints. For a 16-foot deck, 16-foot boards run the full length with no joints — but 16-foot boards are harder to transport and handle. Two 8-foot boards with a staggered butt joint over a joist is a common alternative. UIR staggers all butt joints so no two adjacent boards join over the same joist, which maintains structural integrity and looks better.