Many people assume all silicone sealants perform the same function. In reality, structural silicone and weatherproof silicone are designed for completely different purposes.
Using the wrong product may lead to performance issues or even structural safety concerns.
Structural Silicone
Primary function:
Transfer structural loads between glass and framing systems.
Typical applications:
- Structural glazing
- Curtain wall systems
- Glass façades
- Skylights
Key characteristics:
- High tensile strength
- High modulus
- Excellent long-term durability
- Tested to structural glazing standards
Weatherproof Silicone
Primary function:
Seal building joints against weather infiltration.
Typical applications:
- Perimeter joints
- Expansion joints
- Window perimeter
- Panel joints
Key characteristics:
- Excellent UV resistance
- High movement capability
- Waterproof
- Flexible throughout service life
Comparison
| Feature | Structural Silicone | Weatherproof Silicone |
|---|---|---|
| Load Bearing | Yes | No |
| Waterproof | Yes | Yes |
| UV Resistance | Excellent | Excellent |
| Joint Movement | Moderate | High |
| Structural Application | Yes | No |
Can They Replace Each Other?
No.
Although both are silicone sealants, they are designed according to different performance requirements.
Selecting the correct product should always be based on engineering requirements rather than appearance or price.
Conclusion
Understanding the difference between structural and weatherproof silicone helps improve building safety, durability, and long-term maintenance performance.