Timbers
Grades
Clear Grades
Clear cedar has a limited number of natural characteristics and is specified when appearance of the highest quality is desired. Clear grades of timbers are normally supplied green (unseasoned). When required, seasoning is achieved by air-drying.
Knotty Grades
Knotty cedar presents a more rustic appearance and is typically supplied green (unseasoned) in the appearance and structural grades. When required, seasoning is achieved by air-drying except for grades of Light Framing, Structural Joists and Planks which are available kiln-dried.
Surface Textures
Saw Textured
The saw textured surface, obtained during the milling process which uses either circular or band saws, is present on all four sides.
Rougher Headed
The lumber receives its texture from a milling process which uses roughened planer knives. The rough texture is clearly visible on all four sides.
Surfaced Four Sides (S4S)
The smooth surface on all four sides presents a uniformly sized product with a high quality appearance. Sizes from 2x4 (51mm x 102mm) up to 6x6 in. (152mm x 152mm) are generally available. Larger sizes are produced on special orders.
Grades | Grade | Description |
 | No. 2 and Better Clear This grade consists of D Clear, C Clear, and B Clear. The C and Better Clear grade offers good appearance in high quality, well manufactured lumber. Suitable for high quality landscape structures and as exposed posts and beams in heavy timber construction. WRCEA members produce this grade without cut-outs. In most cases, this grade is sold with a specified allowance of D grade. D Clear grade permits larger and more numerous natural characteristics which are widely accepted in the construction of outdoor structures. Some pieces of D Clear may require trimming to yield clear lengths for the intended use. Available surfaced or rough textured. Grading Rule Paragraph |
 | D and Better Clear Permits somewhat more imperfections than Clear Heart but the grade is still restricted to pieces with excellent appearance. Common specifications are A and Better and A and Better with a percentage of B Grade allowed. Grading Rule Paragraph 2" (51mm) & thinner
3" (76mm) & wider - NLGA 202 b,c,d
- WCLIB 149 b,c,d
2-1/4" (57mm) & thicker
3" (76mm) and wider - NLGA 203 b,c,d
- WCLIB 150 b,c,d
|
 | Appearance Knotty A non structural product manufactured to meet the appearance requirements of quality projects. This material has highly restricted wane allowances to give well defined corners. Contains no holes or other characteristics. Represents good value for appearance end uses. Available rough sawn or rougher headed in nominal 2" (51mm) and thicker sizes. Note: Upon request, Appearance Knotty timbers are available with structural grading. Be certain to specify Appearance Knotty structural lumber when strength characteristics are required. Grading Rule Paragraph |
 | No. 2 and Better Structural Material of this grade is evaluated for structural strength characteristics. The classification includes pieces meeting the grades of Select Structural, No. 1 Structural, and No. 2 Structural. Lumber of this grade is intended for engineered applications where strength is more important than appearance. Available surfaced or rough textured. Grading Rule Paragraph 2"x2" (51mm x 51mm) to 4"x4" (102mm x 102mm) - NLGA 122 b,c
- WCLIB 122 b,c
- WWPA 40.11
2"x6" (51mm x 152mm) to 4"x12" (102mm x 305mm) and wider* - NLGA 124 a,b,c
- WCLIB 123 a,b,c
- WWPA 62.10
5" (127mm) and thicker, width more than 2" (51mm) greater than thickness - NLGA 130 a,b,c
- WCLIB 130 a,b,cc
- WWPA 70.10
width less than 2" (51mm) greater than thickness - NLGA 131 a,b,c
- WCLIB 131 a,b,cc
- WWPA 80.10
Note: Graded as Light Framing
Graded as Structural Joists and Planks |
 | Standard Beams, Posts and Timbers Timbers of this grade are intended for general construction purposes where serviceability is more important than appearance. No structural values are assigned. Available surfaced or rough textured. Grading Rule Paragraph 5" (127mm) and thicker - NLGA 131 c
- WCLIB 131 c
- WWPA 81.11
|
NLGA - National Lumber Grades Authority
WCLIB - West Coast Lumber Inspection Bureau
WWPA - Western Wood Products Association
R List - Export R List (applies to rough sawn/rougher headed lumber)
Sizes | Thickness and Width |
| Nominal (inches) | Nominal (mm) | Rough (inches) | Rough (mm) | Dressed (inches) | Dressed (mm) |
| 5 | 127 | 4-3/4 | 121 | 4-1/2 | 114 |
| 6 | 152 | 5-3/4 | 146 | 5-1/2 | 140 |
| 8 | 203 | 7-3/4 | 197 | 7-1/2 | 191 |
| 10 | 254 | 9-3/4 | 248 | 9-1/2 | 241 |
| 12 | 305 | 11-3/4 | 298 | 11-1/2 | 292 |
| Over 12 | Over 305 | 1/4 off | 6mm off | 1/2 off | 13mm off |
Note:
Full sawn timbers have the same dimension as nominal.
Grade Classifications
Depending upon size, Western Red Cedar is classified as Light Framing, Structural Joists and Planks, Beams and Stringers, or Posts and Timbers. In general, the grades referred to herein are rough sawn.
Light Framing is lumber 2" to 4" (51mm to 102mm) thick and 2" to 4" (51mm to 102mm) wide either rough sawn or surfaced four sides (S4S).
Structural Joists and Planks are rectangular members 2" to 4" (51mm to 102mm) thick, 5" (127mm) and wider, either rough sawn or surfaced four sides (S4S).
Beams and Stringers are rectangular members, either rough sawn or surfaced, 5" (127mm) and thicker with width 2" (51mm) greater than thickness.
Posts and Timbers are square members, either rough sawn or surfaced, 5" (127mm) by 5" (127mm) and larger with width not more than 2" (51mm) greater than thickness.
Specifications
Cedar of all the foregoing grades and surface textures is manufactured by members of the Western Red Cedar Lumber Association (WRCLA). To ensure that the cedar you specify meets the appropriate grade, be certain to specify WRCLA member production. This brochure will help you to select the right grade for the job. A typical sample specification is given below.
Specifying Western Red Cedar for Timber Construction and Landscape Structures
The following information is required when ordering:
| Specification Information Required | Sample Specification |
Species:
Western Red Cedar | WRCLA Western
Red Cedar |
Product Pattern and Intended Use:
Timbers are used in many structures such as commercial, industrial and residential buildings; and in engineered and landscape structures. Specify the surface finish by choosing Surfaced Four Sides (S4S) rough sawn, or rougher headed | Rough Sawn |
Size:
Specify the nominal size of the product. | 6x8 Standard Sawn |
Grade:
The grade of the product Knotty governs its overall quality. Refer to WRCLA specification literature or grading rule books for available grades. | Appearance Knotty Structural timbers |
Grading Agency Paragraph:
To ensure that the product meets a written standard, an agency grading rule paragraph or equivalent grade should be referenced. | Meeting NLGA/WCLIB para. 130cc upgraded for appearance qualities |
Moisture Content:
Specify whether the product is to be green (unseasoned) or dried. | Green |
Surface to be exposed:
Specify the application orientation to assist the supplier in shipping the right product for the job. | Sawn Faces |
Quantity:
Express in linear feet | 400 |
Hot-dipped galvanized, aluminum and stainless steel fasteners are all corrosion-resistant and can be used to fasten Western Red Cedar. Other types of nails are not recommended. They can rust and disintegrate and react adversely with the natural preservative oils present in cedar resulting in unsightly stains and streaks. Copper nails also react with cedar and should not be used. Stainless steel fasteners are the best choice, especially if the wood is to be finished with transparent or semi-transparent stain. Use No. 304 stainless steel for general applications and No. 316 for seacoast exposure.
Large members require timber connectors other than nails. Bolts, lag screws, split rings and shear plates, and custom made hardware are commonly used in heavy timber structures where the joint's strength must be greater than that which could be achieved with nails. These types of connectors should be corrosion-resistant or suitably coated to prevent corrosion and staining. Generally, the design of mechanically fastened joints must take into consideration a variety of factors such as end- and edge-spacing distances, moisture content, service conditions, and the effect of the number of connectors used. Because the cost of fabricating and installing connections may amount to a large percentage of the cost of a heavy timber structure, it is important to engineer the details of a structure before designing the timber members.
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