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Formerly: Dow Corning DefendAir 200

Silicone Liquid Applied Air and Weather Barrier

5GL Unit | 24 units per pallet

This product can only be shipped to Alabama, Arkansas, Florida, Georgia, Mississippi & Tennessee

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Availability: In stock



DOWSIL DefendAir 200 is a permeable air barrier used for new construction and renovation applications on many substrates including concrete, OSB, exterior sheathing, preformed panels, plywood, wood or steel stud walls.


Product Data Sheet


DOWSIL DefendAir 200 is a 100% silicone liquid applied Air and Weather Barrier designed to protect against air infiltration and water penetration. The vapor permeable, one component, water-based coating cures to form a flexible membrane that is impervious to water but has the ability to “breathe,” allowing water vapor to escape from inside the substrate. The coating provides long-term protection from air and water infiltration; normal movement imposed by seasonal thermal contraction and expansion; ultraviolet radiation; and the elements. The coating maintains its water protection properties even when exposed to sunlight, rain, snow, or temperature extremes. There is not a limit on exposure time before being covered by the exterior cladding. DOWSIL DefendAir 200 can be applied between -6°C (20°F) and 38°C (100°F) to a clean, dry surface.
Features & Benefits 
  • UV Resistant – Long term resistance
  • Provides long-term air and water protection properties even when exposed to sunlight, rain, snow, or temperature extremes.
  • Excellent weatherability – Temperature extremes of -15°F to 300°F
  • Meets National Fire Protection Association (NFPA) Class A Fire Rating
  • NFPA 285 – Pass1
  • Ease of Installation – One coat installation 
  • Air tight – Exceeds industry requirements
  • Primerless adhesion on most substrates
  • Solventless
  • Elastomeric – Accommodates building movement
  • Seamless – Cured membrane is continuous and does not form seams or laps
  • Nail sealability
  • Low VOC
  • Compatibility – Compatible with Dow Corning Sealants, Dow Corning 123 Silicone Seal, Dow Corning Transition Strips, and Dow Corning Molded Corners 

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