Regrind Styrofoam — Regrind styrofoam is exactly what it sounds like, old styrofoam cups, plates, packing, etc. ground up into pieces from 1/4" down.  The ground up styrofoam is mixed into the concrete and either applied by hand or sprayed on.

Regrind Styrofoam — Regrind styrofoam is exactly what it sounds like, old styrofoam cups, plates, packing, etc. ground up into pieces from 1/4" down. The ground up styrofoam is mixed into the concrete and either applied by hand or sprayed on. (Michael South)