Preservative Treated Wood

When you want to use wood that is not naturally decay resistant in a wet application (outdoors, for example) or where it may be at risk for insect attack, you need to specify preservative-treated wood. This is lumber that has been chemically treated to make it unattractive to fungi and other pests. In the same way that you would specify galvanized steel where it would be at risk of rusting, you specify treated wood where it will be used in a setting conducive to decay. Also like galvanized steel, treated wood has a shell of protected material surrounding an unprotected core. So long as this shell stays intact, the core will be protected.

Wood does not deteriorate just because it gets wet. When wood breaks down, it is because an organism is eating it as food. Preservatives work by making the food source inedible to these organisms... Preservative Treated Wood.pdf (97 KB)

Fire Retardant Treated Wood

Where flame-spread ratings of 75 or less are stipulated in building codes, most lumber and plywood must be treated or coated to reduce flame spread over the surface of the material. Two most common methods of reducing the flame spread rating are by pressure-impregnation with water-borne salts and by surface coating with fire-retardent chemicals.

This section describes the chemical means used to reduce flame spread on wood products. Information on the importance of flame-spread rating to building construction is covered in greater detail in our Wood Reference Handbook... Fire Retardant Treated Wood.pdf (88 KB)

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