Interior self-levellers, also known as self-levelling compounds or self-levelling underlayments, are specialized flooring products used to create a level and smooth surface for the installation of various floor coverings. They are commonly used in residential and commercial applications to level uneven or rough subfloors before the installation of tiles, hardwood, laminate, or other types of flooring.

Self-levelling compounds are typically cement-based materials that can flow and settle into level positions when poured. They have excellent self-levelling properties, allowing them to spread and settle to create a flat and even surface.