These rugs are expertly power-loomed using only premium quality Polypropylene (PPL). They are made using flat-weave loop construction. The loop construction gives these rugs a softer feel underfoot as well as a more textured and thicker appearance. They are completely weather resistant and suitable outdoors all year round. Being made from PPL moisture will have no effect - these rugs are both mildew and mold-resistant to ensure carefree maintenance. They also have the advantage of being UV resistant.