TimberTech Decking Calculator
Enter your deck’s length and width, pick a TimberTech board width and length, and this calculator works out how many boards you need — based on TimberTech’s real board coverage math (board width plus a 1/8-1/4 in gap, divided into your total deck area).
Quick Answer
Enter your deck’s length and width, pick a TimberTech board width and length, and this calculator works out how many boards you need — based on TimberTech’s real board coverage math (board width plus a 1/8-1/4 in gap, divided into your total deck area).
TimberTech Decking Calculator
Enter your values below for an instant result, then see the formula, worked example, and common mistakes.
Enter your deck dimensions and click calculate.
How to Use This Calculator
Get the total length and width of the deck surface in feet. For non-rectangular decks, split the area into rectangles and add the square footage together.
TimberTech’s standard board face is 5.5 in wide; wide-width boards are 7.25 in and narrow-width boards are 3.5 in (Vintage Multiwidth line). Pick the width and stock length (12, 16, or 20 ft) you plan to install.
TimberTech specifies a 1/8 in to 1/4 in gap between boards for drainage and expansion; 3/16 in is the typical spacing used with CONCEALoc hidden fasteners.
10% covers most rectangular layouts to allow for end-cuts, staggered seams, and mistakes; increase to 15% or more for diagonal patterns, picture-frame borders, or decks with lots of cutouts.
Formula
Effective board coverage (sq ft) = (board width in inches + gap in inches) / 12 x board length in feet.
Boards needed = Deck area (sq ft) / effective board coverage, rounded up, then increased by your waste buffer.
Reference Table: TimberTech Board Coverage by Width and Length
| Board width | Board length | Approx. coverage per board (with 3/16 in gap) |
|---|---|---|
| 5.5 in (standard) | 12 ft | 5.7 sq ft |
| 5.5 in (standard) | 16 ft | 7.6 sq ft |
| 5.5 in (standard) | 20 ft | 9.5 sq ft |
| 7.25 in (wide) | 16 ft | 9.9 sq ft |
| 3.5 in (narrow) | 16 ft | 4.9 sq ft |
Common Mistakes to Avoid
- Ignoring the board-to-board gap when estimating coverage — TimberTech requires 1/8-1/4 in between boards, which slightly reduces how much area each board actually covers.
- Forgetting a waste buffer for end-cuts, staggered end-joints, and picture-framed borders.
- Mixing up joist spacing with board gap — joist spacing (max 16 in on-center for most TimberTech PRO/EDGE boards) is a structural spec, not the same as the small gap left between adjacent deck boards.
- Not rounding up to full boards — lumber yards sell full-length boards, so a calculated 25.3 boards means you actually need to buy 26.
When the Estimate May Be Wrong
This is a material-quantity estimator based on TimberTech’s published board dimensions and spacing guidance, not a structural plan. Diagonal or herringbone patterns, picture-frame borders, large cutouts (hot tubs, stairs), and multi-level decks will need a higher waste buffer than a simple rectangular layout. Always confirm joist spacing and fastening requirements against TimberTech’s current installation guide for your specific product line before building.
FAQs
How many TimberTech boards do I need for a 12×16 deck?
For a 192 sq ft deck using standard 5.5 in wide, 16 ft boards, you need about 26 boards before waste, or 29 with a 10% buffer — enter your own dimensions above for an exact count.
What is the standard gap between TimberTech deck boards?
TimberTech specifies a 1/8 in to 1/4 in gap between boards for drainage and thermal expansion; 3/16 in is typical with CONCEALoc hidden fasteners.
What board lengths does TimberTech offer?
TimberTech deck boards are commonly available in 12 ft, 16 ft, and 20 ft lengths, with width options of 3.5 in (narrow), 5.5 in (standard), and 7.25 in (wide) depending on the collection.
Does this calculator account for joist spacing?
No — this tool estimates decking board quantity and area coverage only. Joist spacing (typically max 16 in on-center for TimberTech PRO/EDGE) is a separate structural requirement; check TimberTech’s joist spacing guide for your product line.
Sources and Methodology
Board dimensions, standard lengths, and board-gap spacing sourced from TimberTech’s official product and installation guidance (timbertech.com: deck board thickness guide, joist spacing guide, and “how to calculate how much decking you need” guide). Coverage-per-board math verified against TimberTech’s own worked example (16 ft x 5.5 in board = 7.2 sq ft).
