Description

Product Data Sheet

DOWSIL™ 899 Silicone Glazing Sealant is a high-performance, one-component neutral-cure silicone sealant engineered for glazing, sealing, and weatherproofing applications in commercial and residential construction. This RTV silicone sealant cures upon exposure to atmospheric moisture to form a durable, flexible, watertight bond with excellent long-term weather resistance.

Designed specifically for window and door fabrication, DOWSIL™ 899 provides outstanding primerless adhesion to many common construction materials including glass, aluminum, wood, vinyl, plastics, and painted surfaces. Its versatile formulation makes it ideal for both primary bedding and backbedding applications where strong adhesion and reliable sealing performance are required.

The sealant features a fast cure profile with approximately 3 minutes of tooling time, helping improve production efficiency in glazing and assembly operations. Once cured, it forms a flexible silicone rubber seal capable of accommodating ±25% joint movement while maintaining adhesion and weatherproof integrity in dynamic building environments.

DOWSIL™ 899 is engineered to resist UV exposure, rain, snow, ozone, humidity, and temperature extremes ranging from -40°F to 300°F (-40°C to 149°C). Its long-term flexibility and excellent environmental resistance help maintain durable glazing seals in demanding exterior applications.

The non-sag consistency allows for clean and controlled application in vertical and horizontal joints, while the neutral-cure chemistry minimizes substrate corrosion and improves compatibility with sensitive building materials. Available in clear and gray, the sealant supports a wide range of glazing and fenestration projects.

Common applications include:

• Window and door backbedding
• Primary glazing applications
• Glass-to-frame sealing
• Aluminum, vinyl, and wood sash glazing
• General weatherproofing joints
• Commercial and residential fenestration assembly
• Skylight and glazing system sealing