Perfect Block ICCF is an insulated composite concrete form (ICCF / ICF) made from 100% recycled expanded polystyrene (EPS) ground into an aggregate. Mixed with Portland cement, proprietary additives, and water, then cured in a mold. After which, the ICCF/ICF form is a sturdy, rigid, and dense block. The block form has to be strong and dense to hold the extreme pressures exerted on it when grouted solid with heavy wet concrete grout with an 8-9 inch slump. The block's hardness makes it difficult for rodents and insects to burrow into it.