Preservative-treated wood is wood which has been surface coated or impregnated by means of pressure with chemicals which improve resistance to damage from decay and insect attack.
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Fire-Retardant Treatment and Coating
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.
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