Dryvit Backstop NT-VB : Class I Vapor Retarder

  • Includes a reinforcing fabric at sheathing joints
  • Bonds to most construction materials
  • Fluid applied/Fast drying
  • Can be exposed for 180 days
  • Ensures a continuous film barrier across transitions
  • No need for multiple products
  • Easy to use
  • Not subject to tear off or damage from wind

Dryvit Products

Contact Us


Dryvit Backstop NT-VB is a flexible, polymer-based, noncementitious, air/vapor/water-resistive barrier, which resists water penetration, eliminates air infiltration and is classified as a Class I Vapor Retarder over vertical above grade walls. Questions? Contact Us.

Available in two versions:
• Backstop NT-VB is applied using a trowel, or texture spray equipment.
• Backstop NT-VB Spray is applied by airless spray equipment.

Dryvit Backstop NT-VB is designed for use with all building claddings, as well as Dryvit EIF systems. When used with the Dryvit AquaFlash System or Dryvit Flashing Tape™, Backstop NT-VB provides an effective air/vapor/water-resistive barrier for acceptable substrates.

Benefits: Backstop NT-VB is used straight out of the pail after an initial spin up to provide a continuous membrane with ease of application. The liquid applied coating dries quickly and serves as an excellent surface for adhesively attaching EPS. Backstop NT-VB is seamless and will not tear. Additionally, it is stable under air pressure differences and will not be affected by wind.

Working Time: Backstop NT-VB is a water-based noncementitious material and will not set-up in the pail. Keep pail covered when not in use to minimize skinning.

Drying Time: The drying time is dependent upon the air temperature, wind conditions and relative humidity. Under average drying conditions [70 °F (21 °C), 55% R.H.], Backstop NT-VB will be dry to the touch within 2 hours and cure in 6 hours.

Testing Information: For test data refer to the chart included with this document.

Application Procedure: For complete application instructions refer to, DS831.

Job Conditions: Air and surface temperature for application of Backstop NT-VB products must be from 40 °F (4 °C) minimum to 100 °F (38 °C) maximum and must remain so for a minimum of 12 hours.

Temporary Protection: Shall be provided at all times until membrane is dry and shall not be exposed to weather for longer than 180 days prior to installation of the specified cladding.