SOPRASEAL LM 204 VP is a one-component, 98% solids content, liquid applied, vapor-permeable air barrier membrane used in wall construction. SOPRASEAL LM 204 VP is STPE technology that has excellent freeze-thaw characteristics and superior curing in low relative humidity and low temperatures. SOPRASEAL LM 204 VP doesn’t shrink and requires less wet film to achieve dry film thickness. This moisture curable hybrid material is a non-flammable vapor permeable air barrier, which provides moisture protection behind wall claddings such as brick, siding, metal panels, EIFS and stucco. Utilization of a drainage plane is required for stucco cladding.

Product Properties

  • Air Permeability ASTM ASTM E2178
  • Air Permeability ASTM ASTM E2357
  • Vapor Permability ASTM ASTM E96 (Procedure B)


SOPRASEAL LM 204 VP can be applied down to 25°F (-4°C) without the use of additional additives. The most effective application method utilizes spray equipment but a 3/4” (19mm) nap roller or a paint brush may be used. Once the application is complete, inspect the wall for any light areas, blisters, holes or areas that need attention. Please refer to SOPREMA specifications and installation instructions for additional application guidelines prior to use.

Testing & Approvals

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