A waterproofing membrane (commonly referred to as a waterproof sheet or barrier membrane) is a high-performance, impermeable material engineered to prevent water infiltration, protect structures from moisture damage, and ensure long-term water resistance in construction, civil engineering, and infrastructure projects. Available in diverse types—including HDPE waterproofing membrane (high-density polyethylene, ideal for rigid, durable applications), EPDM rubber membrane (flexible, suitable for irregular surfaces), PVC membrane (cost-effective for roofing and basements), and bituminous membrane (asphalt-based, excellent for underground structures)—it adapts to varied project needs with strong resistance to water, chemicals, UV radiation, and mechanical wear. Its primary function is to create a continuous, seamless barrier that blocks rainwater, groundwater, or seepage from penetrating building components (e.g., roofs, basements, foundations) or civil structures (e.g., tunnels, dams, reservoirs), avoiding issues like mold growth, concrete deterioration, and structural weakening. Waterproofing membranes are widely used in critical applications such as residential and commercial roofing (preventing leaks and extending roof lifespan), basement and foundation waterproofing (shielding below-ground spaces from groundwater), tunnel construction (protecting inner linings from water pressure), water storage facilities (ensuring zero leakage in tanks and reservoirs), and coastal engineering (resisting saltwater corrosion in seawalls). Unlike traditional waterproofing methods (e.g., liquid coatings or mortar mixes), modern waterproofing membranes offer superior durability (with service lives of 20–50 years), easier installation (supporting heat welding or adhesive bonding for seamless joints), and low maintenance (requiring minimal repairs over time). They also comply with global standards (e.g., ASTM, EN) to guarantee consistent water resistance, tensile strength, and environmental stability. Whether for safeguarding buildings, preserving infrastructure, or ensuring water containment, a high-quality waterproofing membrane is an indispensable component in modern construction, delivering reliable moisture protection and long-term structural safety.