Non-Woven Geotextile Non Woven Non-woven Geotextile, aka Filter Fabric, is a “felt like” material composed of polypropylene fibers. Filter fabric is typically used in drainage applications where two dissimilar soils meet and where water passes, such as a french drain. The fabric performs two functions: separation and filtration. Other applications include subgrade separation and cushioning beneath geoliners. Non-wovens should ONLY be used where water flows in one direction through the fabric. Clogging can occur with tidal or wave action where the water passes back and forth through the fabric, trapping fine particles within. Clogging can also occur when the drain is in contact with uniformly graded silts. In such cases, it is highly recommended to use a woven monofilament geotextile, which resists clogging. Below are Technical Data Sheets for typical non-wovens used in Texas Visit Mirafi Website for complete technical data.