Waterproof membranes are categorized into Bituminous (SBS/APP), Synthetic Polymer (TPO, PVC, EPDM), and Liquid-applied types. SBS-modified bitumen is ideal for cold regions due to its low-temperature flexibility, while APP is better for high-heat environments. For modern commercial roofing, TPO and PVC are preferred for their UV resistance and energy efficiency. If you are sourcing for underground basements or tunnels, HDPE self-adhesive membranes are the industry standard for preventing water migration.