PolyPropylene is Commonly used to construct berber Carpets. In this case, Polypropylene is commonly referred to as olefin. Large Looped olefin berber carpets are usually only suited for light domestic use and tend to mat down quickly. Polypropylene carpets are known to have good stain resistance. Commercial grade carpets can be glued directly to the floor or installed over a 1/4" thick, 8-Pound density padding. Outdoor grass carpets are usually made from PolyPropylene.