Description
Product Data Sheet
DOWSIL™ 758 Silicone Weather Barrier Sealant is a premium one-component, neutral-cure silicone sealant engineered specifically for sealing weather-resistant barriers, window flashing systems, and fenestration assemblies in commercial and residential construction. Designed to bond challenging low surface energy materials without primer in many applications, this high-performance sealant delivers long-term durability, flexibility, and weather resistance in demanding building envelope systems.
This medium-modulus silicone sealant adheres effectively to polyethylene wraps, polypropylene surfaces, PVC, self-adhered flashing membranes, nonwoven weather barriers, anodized aluminum, painted metals, fluoropolymer coatings, and many other difficult-to-bond substrates commonly used in modern construction. Its primerless adhesion capabilities help reduce installation time and simplify application processes on the jobsite.
DOWSIL™ 758 cures at room temperature to form a durable, flexible silicone rubber seal that resists UV exposure, weathering, moisture, temperature extremes, and long-term environmental aging without becoming brittle or cracking. With ±25% movement capability, the sealant accommodates building movement, thermal expansion, and dynamic joint conditions while maintaining reliable weatherproof performance.
Its low-VOC, non-sag formulation provides clean application and excellent tooling characteristics for vertical and horizontal joints. The sealant is specially designed for low-movement weather barrier and flashing joints such as perimeter window and door installations, wall penetrations, lap joints, and air sealing transitions within building envelope systems.
Common applications include:
- Window and door flashing systems
- Air and weather barrier sealing
- Fenestration perimeter joints
- Wall penetrations for ducts and piping
- Lap joint sealing for weather-resistant barriers
- Polyethylene and polyolefin membrane sealing
- Commercial building envelope applications
