Sealant-Applied Vapor-Permeable Membrane: Let Walls Breathe, Keep Rain Out

Last time: vapor barrier (interior). Today: its counterpart — vapor-permeable membrane (exterior). Same foundation: Multi-layer composite, flexible, high-strength, high-toughness. Windproof, rainproof — stops window leaks and drafts. The key difference: Vapor-permeable membrane lets water vapor pass through. While blocking liquid water completely, it maintains a high moisture vapor transmission rate — venting trapped humidity out of the wall to keep it dry and prevent condensation and mold. Shared strengths with vapor barrier: ? High tensile strength & toughness ? Good peel strength, no delamination ? Plasterable surface Exterior-grade requirements: ?️ Higher waterproof stability for direct weather exposure ☀️ 6+ months UV aging resistance during construction ? Surface bonds tightly with exterior waterproof coatings and stone finishes Where it goes: Exterior side of window, pipe, and envelope joints — paired with interior vapor barrier for the 1+1>2 effect. ? Watch the video to learn more.