Waterproofers are responsible for applying sealants, coatings and other materials to surfaces in order to prevent water from penetrating and causing damage. Responsibilities can include: Cleaning and preparing surfaces for application of sealants or other waterproofing materials. Inspecting roofs and other structures to identify leaks or damage that may require repair before applying a waterproofing product. Applying waterproofing materials to structures such as roofs, concrete slabs, foundations, or decks. Inspecting the material after installation. Coordinating with architects on design decisions related to waterproofing materials. Applying liners to walls or floors to prevent water damage.