Dryvit Backstop DMS: Air Barrier & Adhesive
Dryvit Backstop DMS is a polymer-modified cementitious, sprayable, dry mix, water-resistive membrane/air barrier, and adhesive for use with Dryvit Outsulation systems. Over sheathing substrates, joints are treated with Backstop NT-Texture and Grid Tape prior to Backstop DMS application. Questions? Contact Us.
Dryvit Backstop DMS is applied over acceptable substrates and used to provide a water-resistive membrane and to adhere expanded polystyrene insulation board in a single step. Backstop DMS is specifically formulated for spray applications but may also be used for non-spray applications (e.g. troweling onto substrates and notching).
Working Time: After mixing, the working time of the Backstop DMS is approximately 2-3 hours depending on ambient weather conditions.
Drying Time: Drying time of the Backstop DMS mixture is dependent on the air temperature and relative humidity. Under average drying conditions 70 °F (21 °C), 55% R.H., the Backstop DMS will dry in 48-72 hours. Backstop DMS develops full strength in 28 days, similar to other cementitious materials. Allow the Backstop DMS to dry for a period of at least 48 hours prior to rasping to allow the Backstop DMS mixture to form a positive bond. The installed insulation board should not be disturbed until an adequate bond has developed. Cooler, damp conditions will require longer waiting periods.
Testing Information: For individual test data on this product’s properties, refer to the chart included with this document.
Job Conditions: Air and surface temperatures for application of the Backstop DMS must be 40 °F (4 °C) or higher and must remain so for a minimum of 48 hours. Backstop DMS shall not be applied to the substrate when substrate and/or air temperatures are above 100 °F (38°C).
Temporary Protection: Shall be provided at all times until the adhesive, base coat, finish, and installation of permanent flashings, sealants, etc. are completed to protect the wall from inclement weather and other sources of damage.
• Exterior grade gypsum sheathing meeting ASTM C 1396 (formerly C 79) requirements for water-resistant core or Type X core
• Exterior sheathing having a water-resistant core with fiberglass mat facers meeting ASTM C 1177
• Exterior fiber reinforced cement or calcium silicate boards
• Unglazed brick, cement plaster, concrete, or masonry