Decking board thickness choosing guide


Are you working on a Decking or Boardwalk project and trying to figure out what decking board thickness to choose? Looking to understand decking board dimensions and joist spacing?

What are joists?

Joists are horizontal structural members usually made of wood. They are used as a framing system in flooring projects and placed upon a central support beam. Joists provide support and stiffness to the decking boards fastened on top of them.  

How far apart should deck joists be spaced?

Deck joists are usually spaced 12 inches or 16 inches on center. Deck joist spacing depends on the size and thickness of the decking boards used. For thinner decking boards mve the joists to a 12 inch on center, for thicker ones you are good to go with 16 inch on center. We do not recommend wider joist spacing for decking boards as they will bounce and will give an uncomfortable feeling under your foot.

Decking board lumber grade

The fewer defects contained in a piece of lumber, the stronger it will be. Higher grades of lumber (clear, select, or 1) have fewer flaws, and will, therefore, be stronger. A common choice for construction framing is 2-grade lumber. While not as strong as the higher grades, the flaws in 2-grade lumber are generally not enough to seriously weaken the boards. Avoid using 3- or 4-grade lumber for structural framing applications. If you are hand-picking boards, examine them for knots and other flaws.

Decking board thickness dimensions

Deck layout

Plan the layout of your deck carefully; planning saves time and money, reducing cutting and waste. For example, no cuts are required if the width of your deck is designed to match a typical decking board length (e.g. 8’, 10’, 12’, 14’, 16’ – or roughly 2.4m, 3.0m, 3.65m, 4.27m, 4.87m)

Boardwalk & Decking Commercial vs residential decking board use

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