USG Durock™ CST™ Moisture Vapor Reducer

Brand CST™

Penetrating concrete moisture barrier utilizing reactive chemistry

USG Durock™ CST™ Moisture Vapor Reducer is a single component moisture mitigation system that reacts with concrete to create a permanent moisture barrier 2-4 mm below the surface.

Features and Benefits

USG Durock™ CST™ Moisture Vapor Reducer contains moisture-responsive particles that swell and contract to help regulate moisture vapor transmission rates at the surface of concrete.

  • Effective at managing MVER up to 10 lbs. (ASTM F1869) and RH up to 99% (ASTM F2170)
  • Silicate-free penetrating concrete moisture barrier
  • Moisture-responsive particles help create a permanent membrane 2-4 mm below the surface
  • Maintains a consistent pH at the surface level
  • Maintains surface profile for optimal bond of patching and leveling compounds and coatings
  • Dries in as little as 1 hour
  • Can be applied 24 hours after concrete is poured


USG logo -


United States Gypsum Company

550 West Adams Street

Chicago, IL 60661

© 2020 USG Corporation