What movement class do you typically specify for curtain wall joints? Let us know below. 👇 #ASTMC920 #BuildingEnvelope #SealantSpecs #ConstructionQuality #FacadeEngineering #ElastomericSealant

But not all sealants are created equal. If you are specifying or installing a joint sealant for a critical application (curtain wall, plaza deck, or window perimeter), one standard should be non-negotiable: .

Beyond the Tube: Why ASTM C920 is the Gold Standard for Elastic Joint Sealants

When a building moves, its skin must follow. From thermal expansion and wind sway to seismic drift and concrete shrinkage, modern structures are in constant motion. The thin line of defense against water intrusion, air leakage, and energy loss is the sealant .

Here is what you need to know about the industry’s benchmark for elastomeric joint sealants. Unlike general-purpose caulks (which meet ASTM C834), ASTM C920 is designed for dynamic movement . This standard tests a sealant’s ability to stretch, compress, and recover under real-world conditions.