Caulking fiber, also known as oakum, is a material used to seal cracks and gaps in buildings. It is made from fibers of hemp or jute that are soaked in tar or a similar substance. SEALANT is a material used to fill in gaps and prevent leakage. PUTTY is a type of SEALANT made from a combination of clay, chalk, and linseed oil. LEAKY is an adjective used to describe something that has a hole or crack that allows liquid or gas to escape. All of these materials are used in caulking fiber to create a waterproof seal.