... three layers, it supports a high strength, better effect of waterproof, there will be no warped edge, no hallowing.Product ... .Application Scope1, This material can be used in some building waterproof construction, such as all kinds of roofing, basement, tunnel ... ChangeTensile Strength Retention% ≥80Glue Snaping Extension Retention Rate % ≥70 Composite Plastic Waterproof Membrane Waterproofing Material