Silicone Hydrophobic Powder (also known as Silicone Water Repellent Powder or Hydrophobic Agent Powder) is a high-performance, silicone-based powdered additive designed to impart excellent water repellency to cement-based and gypsum-based dry-mix mortars. It appears as a white to off-white, free-flowing fine powder that easily disperses during mixing and forms a durable hydrophobic film on pore surfaces after drying.
This additive significantly reduces water absorption, prevents efflorescence, and enhances long-term durability without affecting breathability or adhesion.
Key Features & Advantages
- Strong Water Repellency — Dramatically reduces water absorption (up to 90%+ reduction) and prevents penetration of rain/moisture.
- Anti-Efflorescence & Stain Resistance — Minimizes salt efflorescence and surface staining from water ingress.
- Breathable & Vapor Permeable — Allows moisture vapor to escape, preventing internal condensation and damage.
- Low Dosage Efficiency — Effective at 0.1–0.5% by dry mix weight, minimal impact on other properties.
- Excellent Compatibility — Works well with cement, gypsum, HPMC, RDP, and other common admixtures.
- No Effect on Strength/Adhesion — Maintains compressive strength, bonding, and workability.
- Long-Lasting Durability — Provides permanent hydrophobicity even after years of exposure.
- Eco-Friendly — Low-VOC, silicone-based, suitable for green building projects.
Typical Applications
- Exterior wall renders and plasters
- Waterproof skim coats and wall putty
- Tile adhesives and grouts (especially exterior)
- Gypsum-based plasters and joint fillers
- Cement-based waterproofing mortars and repair compounds
