Decking Specifications

Sizes and Grades

Sizes and Spans of Western Red Cedar Decking

Aged Western Red Cedar Knotty Deck with Ocean ViewWRCLA Western Red Cedar decking is available in a selection of thicknesses, widths and lengths as shown in the table opposite.

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.


WRCLA Architect Clear™

The ultimate in durability and appearance. Its fine grained appearance will meet the needs of the most demanding clients. All aspects of manufacturing and quality control are performed to the highest standards of the lumber industry. Architect Clear decking should be specified when only the best will suffice. This exclusive product is usually manufactured to individual order. Available seasoned or unseasoned.

WRCLA Custom Clear™

A quality product that combines the stability and durability of Western Red Cedar with a sophisticated clear appearance that will please the most discriminating taste. Its finely machined surface shows limited characteristics which do not detract from its natural good looks. Custom Clear decking can be used directly on the job and is a natural for custom residences and other applications where fine woodwork is desired. Available seasoned or unseasoned.

In addition to these clear grades, some suppliers will also offer clear grades of A & Better, B, C and D & Better S4S for decking purposes.  They are usually furnished as A & Better allowing a % of B or C & Better allowing a % of D.

WRCLA Architect Knotty

Rustic charm at its best. Durable, well manufactured Western Red Cedar decking that comes ready to use. This sound and tight knotted decking limits both the size and quality of characteristics to meet the highest buyer expectations. The smooth, skip-free dressing over the entire face makes it the ideal deck surface. The top choice where the natural beauty and lasting charm of a knotty deck are desired. Available seasoned or unseasoned.

WRCLA Custom Knotty

Widely used by homeowners and builders, this category of knotty decking combines the high manufacturing standards required for deck boards with a hole-free knotty appearance. This category limits the size and quality of characteristics to provide an economical and enjoyable knotty deck. Custom Knotty decking may be applied as received and is a natural choice for home deck builders, residential builders and commercial applications where a durable knotty material is desired. Available unseasoned only.


Cedar Railing Diagram