Sikasil® C Silicone sealant for construction and sanitary applications Sikasil® C is a 1-part, neutral curing, non-corrosive multipurpose elastic joint sealant for sealing many types of joint configurations. It has a primerless application and good adhesion to most construction materials. Provides an elastic and flexible waterproof seal with resistance to UV, fungus and mildew. Movement capability ±25 %. Internal and external use.