Sikasil® WS-305 AM

Neutral-curing silicone weatherproofing sealant

Sikasil® WS-305 AM is a neutral curing silicone sealant with high movement capability and excellent adhesion to a wide range of substrates. It is particularly suited as a weather seal for curtain walls and windows. Sikasil® WS-305 AM is typically used for weathersealing curtain walls and glass butt joints or as a perimeter weather seal for windows, doors, and window walls. Further, the product properties of Sikasil® WS-305 AM are beneficial for field and shop applications related to rainscreen facades, prefabricated exterior wall systems and modular construction.  

  • Meets the requirements of ASTM C920 Type S, Grade NS, Class 50, Use M,G,A
  • Meets the requirements of ASTM C1184, Type S, Use G,A
  • Meets the requirements of AAMA 803.3 and 808.3
  • ASTM E84 with a Flame Spread Index of 15 (Class A acc. to IBC)
  • Los Angeles Research Report (LARR) approved
  • Good UV and weathering resistance
  • Adheres well to many substrates including concrete, glass, metals, coated and painted metals, vinyl, and wood.