Cot PEHD Rainplus 63/88° Cot PEHD Rainplus 63/88° is a polyethylene high density (PEHD) waterproofing membrane designed for use on roofs. It is made of a cross-linked polyethylene with a high molecular weight that is highly resistant to tears, punctures, and UV radiation. The 63/88° version features a raised embossment design that helps prevent water pooling and ensures that rainwater is diverted away from the roof. The membrane is also self-healing, meaning that any punctures or tears will heal themselves over time. It is ideal for use on flat or low-slope roofs, and is available in a variety of colors and sizes.