Dowsil 791 Silicone Weatherproofing Sealant
Dowsil 791 Silicone Weatherproofing Sealant
📋 Product specifications are for reference only.
All product details should refer to the official manufacturer documents. For official product data sheets or technical enquiries, please contact us via WhatsApp.
Dowsil 791 (formerly Dow Corning 791 / Dow 791) is one of the world's most widely used building sealants. A neutral-cure silicone formula with high joint movement capability and outstanding weatherability, suitable for curtain wall glazing, window/door joints, and exterior waterproofing. Known in Hong Kong's construction industry as '791 silicone' or '791 sealant'.
Product Features
Dowsil 791 (also known as Dow 791) is a one-component, medium-modulus, neutral-cure silicone elastic sealant designed for building weatherproofing applications. Once cured, it forms a flexible and durable silicone rubber seal that provides long-lasting waterproof protection. Available in multiple colours to match various architectural finishes. As the world's best-selling 791 silicone, Dowsil 791 is widely specified across Hong Kong's construction industry.
- Ready to use straight from the cartridge
- Medium modulus with high joint movement capability
- Outstanding weatherability — virtually unaffected by sunlight, rain, or ozone
- Neutral cure — non-corrosive to metals, concrete, stone, and other substrates
- Low odour for a healthier working environment
- Low embodied carbon — carbon-neutral certification available (PAS 2060)
- Contributes to green building certification credits
Applications
- Curtain wall weatherproofing joints
- Exterior building facade waterproofing
- Window and door frame sealing
- General building waterproofing
- Metal cladding panel joint sealing
Specifications
| Item | Specification |
|---|---|
| Type | One-component neutral-cure silicone sealant |
| Modulus | Medium |
| Movement capability | High |
| Cure type | Neutral cure (moisture cure) |
| Packaging | 300ml cartridge |
| Colour | Multiple colours available |
Dowsil 791 vs 795 vs 995 Comparison
| Model | Application | Modulus | Features |
|---|---|---|---|
| Dowsil 791 | Exterior weatherproofing | Medium | Most versatile, suits most building sealing |
| Dowsil 795 | Structural bonding | Medium | Can withstand wind loads, supports glass panels |
| Dowsil 995 | Structural curtain wall | High | Hurricane-rated structural sealant, high mechanical strength |
In short: 791 for weatherproofing, 795 for structural sealing, 995 for demanding structural bonding. Most exterior building waterproofing projects use 791 silicone.
FAQ
What is the difference between Dowsil 791 and Dow Corning 791?
They are the same product. Dow Corning rebranded to DOWSIL in 2018; the formulation remains unchanged. Searching for Dow Corning 791 or Dow 791 will lead to Dowsil 791.
What applications suit 791 silicone?
Dowsil 791 is ideal for exterior walls, curtain wall glazing, and window/door frame weatherproofing. Its high movement capability accommodates thermal expansion and contraction, the neutral cure does not corrode substrates, and its weatherability provides long-lasting durable performance.
Should I choose 791 or 795?
For general weatherproofing, use 791. For structural bonding (e.g. fixing glass panels to withstand wind loads), use 795. Dowsil 791 is more affordable, has a broader application range, and is the most commonly used building silicone sealant.
Why is 791 so popular?
Dowsil 791 (Dow 791) has decades of proven market performance, a neutral-cure formula that does not corrode substrates, and high movement capability to accommodate structural movement. It is used on major building projects worldwide and remains the construction industry's go-to weatherproofing silicone.
Pricing
Contact us via WhatsApp for current pricing. We offer counter collection from our Mong Kok store and delivery throughout Hong Kong.
For detailed application methods, coverage rates, and technical parameters, please refer to the official product data sheet.
