A formulation is mixed and applied to structural members in a plastic form and then cured. The formulation uses waste materials as an aggregate in a concrete like mixture, including fly ash, wood pulp or the like, with a minimum of cement or other adhesive. The formulation when cured adheres to steel and other construction materials. The formulation provides an insulation of R-2 per inch of thickness. Essentially the formulation increases the time during a fire before a structural member loses its load bearing capacity under intense heat. The cured formulation accepts nails and screws and it can also be saw cut. The formulation can be treated with other ingredients to render it termite and mold resistant.