text: Commercially available siliconates include potassium methyl siliconate (CAS 31795-24-1, CHKOSi) and sodium methyl siliconate (CAS 16589-43-8, CHNaOSi). These are supplied as a concentrate in water with an active content of between 30 and 40% by weight. This solution is further diluted in water prior to their application by spraying, dipping or rolling to a mineral building material, such as brickwork, to make the surface water repellent. The dilution is clear, stable with a high pH of 13 to 14. When applied to a surface the siliconate reacts with carbon dioxide in the air to form an insoluble water resistant treatment within 24 hours.
  :CHKOSi +  silanol functional substrate OHSi → CHOSi + KOH
  The methyl group has now attached itself to the substrata.
  :2KOH + CO → KCO + HO
  The salts formed by this reaction are often the cause of white efflorescence when too much of the solution is applied to the surface.