Thin-set mortar is a type of adhesive used in tile installation. It is a mixture of cement, fine sand, and water-retaining agents, which allows it to bond tiles to surfaces like concrete, cement backer board, or drywall. Thin-set mortar is applied in a thin layer, typically no more than 1/4 inch thick, making it ideal for various tile types, including ceramic and porcelain. This mortar is known for its quick drying time and strong adhesion properties. It is available in both modified and unmodified versions, with the modified type containing additional polymers for enhanced performance. Proper mixing and application are essential for achieving a durable tile installation.