Wood impregnated with flame-retardant chemicals, like this Exterior Fire-X lumber from Hoover, is an economical choice for a fire-resistant deck. Hoover's treated southern yellow pine scores a 15 in flame-spread testing (25 or below gets a Class A rating). The company's treated deck heart-grade redwood and cedar have even lower flame-spread values of 10 each. $2.50 per lineal foot for redwood 2x6. Hoover Treated Wood Products Inc.,
Thomson, GA; 800-832-9663.