Abstract: A new and useful preformed, self supporting article is provided, which can function as a tile substrate. The tile substratum has inherent durability, strength and ease of application and reduces the installation process for building tile to such a degree as to be significantly easier and faster than built up substratum and in addition requires no other structural components such as wood or plywood. The tile substrate is formed of lightweight cast or preformed mixture of cement/expanded polystyrene and water, which individually or when assembled together, provide a complete, ready to tile substratum. Individually or in assembly the substratum units are self-supporting, and require a minimum of modification to complete their installation. The units are lightweight by design. Individual units are designed and manufactured to address the majority of common tiled counter top configurations with easy modification or cutting to size.