Backfill Materials Below 12” of Grade. All backfill materials below twelve inches (12”) of grade must consist of crumbling yellow clay, sand, or loam. However, the clay content cannot exceed 35% of the materials, and blue and grey clay are expressly prohibited as backfill. If questions arise as to the clay content of the fill material, then the Contractor must provide documentation approved by the Owner that evidences the clay content at the Contractor’s expense. Source approval by the Owner does not absolve the Contractor of compliance with these requirements. The Contractor may use residual broken or crushed rocks, concrete, bricks, blocks, or other masonry material as fill material for any void or excavation greater than three feet (3’) in depth so long as the materials are no larger than eight inches (8”) in diameter and the materials are free from contamination (i.e. paint, stain, mastic, etc.). ..
