The majority of subsoil is made up from materials that have undergone the leaching process. This process entails said materials being removed from a solid via percolation. Materials such as clay and sand are most commonly what it comprises of.

Clay-based subsoil has been the primary source of material for adobe, cob, rammed earth, wattle and daub, and other earthen construction methods for millennia. Coarse sand, the other ingredient in most of these materials, is also found in subsoil.