Leveler (レベラー) – a self-leveling polymer-modified cement that has high flow characteristics and, in contrast to traditional concrete, does not require the addition of excessive amounts of water for placement. Leveler is typically used over non-level concrete-based slabs or floors for the purpose of creating a level subfloor over which the final finished flooring is installed.
Leveler is also used for the upper layer of concrete foundations where wooden foundation beams are bolted down on them directly. In such cases, the concrete upper surface must be level, as the floor and subsequently the entire structure will be based from it. However, because leveler is significantly softer than concrete and is not used in conjunction with reinforcement, it cannot be used for anything structural.
Note the leveler being poured over the existing concrete and the difference in consistency between them. Leveler can be identified after it has cured by its smooth texture, as well as the hardened flow patterns that remain visible. (See image below)