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Western Red Cedar Decking Span Tables

Save Big On Your Next Deck Project

Are you looking to build the outdoor deck of your dreams but don’t know where to start? Watch this video to get insider tips on how to save big on Western Red Cedar decking. You can literally save thousands of dollars by working with various decking patterns and sizes. Start building your next Western Red Cedar project today.

Span Table and Common Dimensions

WRCLA Western Red Cedar decking is available in a selection of thicknesses, widths and lengths as shown in the table below.

Maximum spans for decking shown in the table are based on a continuous beam with two equal spans and a concentrated load of 220-lb at the center of one span. The true span of the decking board is used, taking into account the thickness of the supporting joist beneath it. Wet end-use conditions and unseasoned (green) lumber sizes are assumed.

Decking Span Illustration

Thickness (in.) Width (in.) Grade Category (in.) Span
1-1/4 4 All clear grade categories 16
1-1/4 4 All knotty grade categories 12
1-1/4 6 All clear and knotty grade categories 16
2 4 All clear and knotty grade categories 24
2 6 All clear and knotty grade categories 24

To help figure the amount of decking needed for a project, use the following linear footage calculator:

To Cover 100 Square Feet of Deck
Nominal Size (in.) Linear Feet
1-1/4 x 4 325
2 x 4 325
1-1/4 x 6 211
2 x 6 211

Check with your local building authority about what span is required in your area.

Common Sizes – Deck Boards

Thickness Width
Nominal (in.) Nominal (mm) Actual (in.) Actual (mm) Nominal (in.) Nominal (mm) Actual (in.) Actual (mm)
Rough (Undressed)
5/4 32 1-1/32 26 4 102 3-9/16 90
2 51 1-9/16 40 6 152 5-9/16 141

Note: These are nominal sizes, actual sizes may vary by manufacturer.