Pressure Impregnated Preservative Treated
Cedar Shakes and Shingles

For long material life span in areas of high humidity, pressure impregnated preservative treated cedar shakes or shingles may be specified. This product will help prevent moss and mildew build up.

Product Grading

The Cedar Shake and Shingle Bureau (CSSB), an industry organization, created and updates the industry's grading rules, known as CSSB-97. These CSSB-97 grading rules are incorporated into the U.S. national building codes International Building Code and International Residential Code, as published by the International Code Council. These are the standard reference guides for commercial and residential projects and have been adopted by most states.

The CSSB maintains a quality control program for grading and inspections. Trained professionals perform random, unannounced inspections of member manufacturers' sites. These inspections ensure that grading rules are applied for product consistency.

The Importance of the Label

Product labels are inserted under each bundle strap and contain the following information: brand name, product grade, product type, independent, third party quality control agency, mill name and contact information, product dimensions, building code compliance numbers, product performance tests the material has passed, UPC code, summary application instructions (usually on reverse), and coverage chart showing bundles per 100 square feet and recommended exposure. Cedar shake and shingle bundles are measured in squares, the amount required to cover 100 square feet.

Labels that state "inspected by in-house inspectors" do not have an outside party inspecting the product, meaning that a company employee has inspected his/her own product.

Design and specification documents should call for cedar shakes and shingles in terms that are more specific than "blue label cedar shingles." There are dozens of uninspected products that have labels similar to those used by third party inspected mills. Quality levels on uninspected products are not monitored and these products are not accepted by building code officials.

Grain

The terms edge grain, vertical grain, and flat grain are used when comparing products and grades. Edge grain and vertical grain refer to annual growth rings for a 45 to 90 degree angle with the product surface. Flat grain refers to product that has annual growth rings that form less than a 45 degree angle with the product surface. Both top grades for shakes (Premium Grade) and shingles (Number One Grade) do not allow any flat grain in the bundle. Up to 20 percent flat grain only is permitted in each Number One Grade shake bundle.

Top quality, edge or vertical grain cedar roofing and siding materials are available in a variety of product types. Lower grades of products allow a mixture of edge and flat grain, knots, and other imperfections. Lower grades are acceptable for some projects; however, this should be verified against installation exposure requirements and local building codes.

Product Qualities and Characteristics

Cedar offers a full range of product benefits. It has high insulation value, which reduces energy consumption throughout the year. Many types of cedar shakes and shingles have been tested and proved to be resistant to wind, impact and fire.

Fire Resistance

Class A, B, and C pressure impregnated fire retardant treated roofing systems are available with cedar shakes and shingles. (See earlier section on pressure impregnated fire retardant treated products).