Single-component Silicone Weather Sealant
This information reflects our best understanding of product composition in 2022.
Silicone sealants include both one-part and two-part products. This Common Product covers one-component silicone sealants used in a variety of weatherproofing applications such as perimeter sealing of doors and windows. They can be applied to a...
Silicone sealants include both one-part and two-part products. This Common Product covers one-component silicone sealants used in a variety of weatherproofing applications such as perimeter sealing of doors and windows. They can be applied to a variety of substrates including glass, various plastics, aluminum, steel, stone, brick, and concrete, and generally can be used for both structural and nonstructural glazing applications. They typically do not require the use of a primer, although primers may be used for some substrates.
Silicones do not absorb ultraviolet (UV) radiation, so they do not degrade like other materials when subjected to sunlight. Thus, they are used in exterior applications requiring high resistance to UV radiation. Silicone weatherproofing sealants are also resistant to ozone, rain, snow, and extreme temperatures and humidity. These sealants are composed of reactive siloxanes and silanes that cure upon contact with moisture in the air. Silicone sealants can be classified as acid-cure (acetoxy) or neutral-cure (alkoxy). Both types release condensation products upon curing, but acid cure silicone sealants release acetic acid, which can be corrosive to some substrates. This CP covers neutral-cure sealants, which release less corrosive chemicals, such as methanol, upon curing.