Abstract: A method of producing extruded synthetic lumber for use in construction matting comprising the steps of first, providing a blend of ground synthetic particles, the blend selected from the group comprising primarily ground high density polyethylene particles and ground polyethylene terephthalate particles in an amount not more than 99.0 percent by weight and a composition of ground styrene-butadiene rubber comprised primarily of tire buffings in an amount from 1.0 percent to about 3.5 percent by weight. The blend is mixed, heated and extruded into dimensional lumber and then cooled. The resulting lumber has a low retained memory and reduced electrosstatic potential.