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Western Red Cedar Lap/Channel Siding


Channel (a.k.a. Lap) Siding is a popular type of siding and is used whenever a rustic appearance is desired. A versatile siding, it can be installed vertically, horizontally or diagonally. In channel siding the profile of each board partially overlaps that of the board next to it creating a channel that gives shadow line effects, provides excellent weather protection and allows for dimensional movement.

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Lap/Channel Siding Grading

Lap sidings are normally supplied in a variety of patterns either green (unseasoned) or dry in clear or knotty grades and with a smooth or saw textured face.

Channel siding is normally supplied in unseasoned knotty grades. The face side is saw textured. Commonly available sizes are 1″x6″, 1″x8″, and 1″x10″. Clear grades are manufactured to order.

Please visit the Siding Grades page for more photos of various siding grades.


Lap/Channel Siding Coverage

Lap Siding Coverage Table for Green (Unseasoned) Siding

Nominal Width (in.) Dressed Width (in.) Exposed Face Width (in.) Linear Feet Factor Board Feet Factor
6 5-1/2 4-3/4 2.53 1.27
8 7-3/8 6-5/8 1.81 1.21
10 9-3/8 8-5/8 1.39 1.16


Lap/Channel Siding Specifications

The following information is required when specifying lap siding products:

Specification Information Required Sample Specification
Western Red Cedar
WRCLA Western Red Cedar
Product Pattern and Intended Use:
Siding is used as an exterior cladding to provide both weather protection and architectural style. The designer may choose from a variety of lap siding patterns specified by name or pattern number.
Lap Siding Pattern WP11
Specify the nominal size of the product.
1 x 6″
The grade of the product governs its overall quality. Refer to WRCLA specification literature or grading agency rule books for available grades.
Select Knotty
Grading Agency Paragraph:
To ensure that the product meets a written standard, an agency grade paragraph should be referenced.
NLGA para. 204a
Moisture Content:
Specify whether the product is to be green (unseasoned) or kiln-dried.
Surface to be exposed:
Specify the application orientation to assist the supplier in shipping the right product for the job.
Sawn face
Express in linear feet the quantity required.
2,000 linear feet