Abstract: A continuous filament non-woven web is disclosed, wherein filaments of the web include an expandable thermoplastic material. Mattings fabricated from the continuous filament non-woven web are also disclosed. The web or matting can be used in sealing applications as it can be cut into desired dimensions and inserted into a cavity. The web or matting allows for introduction and drainage of further fluids in and from the cavity. The extendable thermoplastic material can be activated and foamed to fill a part of or the entire cavity. The sealing can prevent air, water or noise from intruding into the cavity and a space behind that cavity.