The primary reason to choose Magnesium Oxysulfate (MgO Sulfate) board over the more common Magnesium Oxychloride (MgO Chloride) board—especially in roofing and structural applications—comes down to a single chemical enemy: Chlorides.
While both are “MgO boards,” their performance in real-world environments is drastically different. Here is the technical breakdown:
- The “Sweating” Problem (Efflorescence)
Regular MgO Chloride boards are hygroscopic, meaning they naturally absorb moisture from the air.
- Chloride Board: When the board absorbs moisture, the free chloride ions react to form a ...
MAR
2026


